. _ /a> __ r \ Prom the £ibrai'y o//o/?i of 7/yno/) from S/gh/ Bh/Zs Fig 9. Boning Boo's fixed ind/caZ/ng /ece/ fo/~ Zog> of embankment METHOD OF LEVELING 20 BRICKLAYERS’ GUIDE ‘FIELD LEVEL BOOK Hack Sight. Inter. Sight. Fore- Sight. Rise. Fall. Reduced Levels. Dis¬ tance. chains 4 15 lOO'.O 4. 13 .02 100.02 1 5 01 .88 99.14 2 4.86 .15 99.29 3 6.06 1.20 98.09 4 8.02 1.96 96.13 5 12.25 8.46 • • • • • • 3.79 .... 99.92 6 3.04 • • • • • • 5.42 .... 105.34 7 2.15 .89 ... 106.23 7.57 12.60 7.19 .... 5.41 ... 111.64 8.57 2.53 4.66 .... 116.30 9.57 9.37 5.75 . . . . . . 3.62 .... 119.92 10.57 3.94 . 1.81 . . .. 121.73 11.57 25.77 4.04 21.73 4.04 21.73 Total Dis¬ tance. 11.57 Remarks. Bench Mark A 1 peg 2 3 4 5 6 7 Bench Mark B 8 9 10 Bench Mark C The above shows a typical field book. The reduced level of the first point is taken as ioo ft. above a datum level; the levels are all read in feet and hun¬ dredths of a foot; the distances are taken in chains and links, but may be taken in feet and inches. The rise and fall columns should be balanced, also the first and last reading in the reduced levels; these two quantities will equal each other if the computations have been correctly made. Second Method. —The second method is evident from the previous explanations. Third Method. —The method of contouring is the most useful, but takes the longest tim^ to perform it; FOUNDATION 21 it consists in describing upon a plan a series of level lines with a uniform vertical interval between them. To carry out this operation it is usual to erect the instrument on the highest point of any section of the area to be contoured, and from this point to range a number of lines radiating from it, their direction being fixed by taking their bearings. The height of the instrument is then taken, and the man with the meas¬ uring staff is directed up or down each line in succes¬ sion until a number of points of the required vertical interval and their distances from the initial point are determined. This method is most useful for laying out large estates where extensive works are projected, as on such a plan the problems of drainage and roads of convenient and economical gradients can easily be laid down. When the levels of a site are known, and the build ¬ ing is planned, and the position of one of its leading lines is determined, to set out the remaining lines of an ordinary building becomes a simple matter, only requiring great care in the measurements of the parts. If the setting out is rendered difficult through differ¬ ences of level in the paths, a theodolite would very much simplify the operations. Boning Method of Leveling. —This operation is used for the leveling of trenches, ground work, paving, etc. There are three rods in a set; two of these are leveled at a distance of about io ft. apart; a third rod is then leveled at a similar distance, taking care to reverse the long level. The center rod is then removed, and the level transmitted to any point along the line by sight¬ ing or boning over the first and third rods. Fig. io shows the method of using boning rods and setting a curbstone. 22 BRICKLAYERS’ GUIDE Trenching. —When the lines of the building have been laid down and all its salient angles pegged out, the work of excavating the trenches commences. It is absolutely necessary that the trenches should be level along their bottoms. To ensure this, two or more sight rails (as shown in Figs. 6 and 7) are erected over the trench; it is necessary that the side posts of these should be fixed in such a position that they shall not be disturbed by any of the subsequent operations. A level line is sighted through the level and marked on the sight rails; the cross bar is then fixed on each, and a mark is made on the bars plumb over the center of the trench. The width of the trench is marked out with the line and pins (see Fig. 9), and the excava¬ tion is carried on, timbering being inserted as the earth is removed, if required, by one of the methods afterwards described. When the full depth of the trench has been nearly reached, a number of points FOUNDATION 23 are sunk to the exact depth by means of boning rods, the top of which is sighted between two of the sight rails, as shown in Fig. 8. The remaining parts of the trench bottom are then taken out level between the points so determined. A similar process is pursued for sinking a trench for a drain, the variation being that the sight rails have a difference in height neces¬ sary to give the required fall. Embanking. —The method of forming an embank¬ ment is as follows: The center line of the proposed work is ranged out on the ground, and at equal inter¬ vals along the line boning rods are erected, the two extreme rods being first fixed either level or with a difference in height sufficient to give the required gradient; a rod is then erected on each of the intervals determined upon, and boned between the two extreme rods. The embankment is then commenced from one end, the earth being tipped in from carts or wagons until the tops of the boning rods are reached; sufficient earth in excess must be allowed for to compensate for compression and settlement. The width of the em¬ bankment is completed as the work is pushed forward, as shown in Fig. 9. f Timbering for Excavations. —It becomes necessary, where earth has to be excavated to any considerable depth, for foundations or other purposes, to support the sides of the cutting until the sinkings or trenches are filled in, or other action taken to permanently support the sides. This end is attained by means of timber shores, the arrangement of which is modified and governed by several conditions, such as the nature of the soil, the size of the cutting, and the special peculiarities of the particular piece of work under consideration. 24 BRICKLAYERS’ GUIDE There are three typical methods of strutting used for supporting the sides of narrow trenches excavated for foundations or drainage work, shown in Figs. II and 12. FOUNDATION 25 The first, used for firm ground, consists of short upright members, termed poling boards, out of g x i 1 /^ in., usually from 3 to 8 ft. long, placed in posi¬ tion in pairs, one board on each side of the cutting; these are kept apart by struts out of about 4x4 in., or short ends of scaffold poles cut and driven tightly between the poling boards. The strutting is fixed as soon as the trench has been made sufficiently deep. The horizontal distance apart between the adjacent system of strutting varies according to the cohesive strength of the soil, but never less than 6 ft., which is just sufficient to allow a man to work in with effect. The method shown in Fig. 12 is adopted where the earth requires to be supported at shorter intervals than 6 ft., and consists of upright poling boards and struts as before, but with the addition of a horizontal timber termed a waling piece. The process of fixing is as follows: The cutting is made, commencing at one end, and as soon as sufficient earth has been excavated a pair of poling boards and struts is inserted as in the first method; this process is repeated, fresh poling boards being fixed at distances apart varying with the nature of the earth, these distances being in some instances very short. Horizontal members, 4 x 4 in. or upwards, are placed one on each side of cutting and strutted tightly against the poling boards. After about 12 ft. has been thus cleared, the struts which were fixed first are then knocked out; a fresh depth is commenced, and treated in a similar way. . The third method is employed where the earth is very soft, and consists in laying horizontally boards, usually 9x1^ in., against the sides of the excavation; the boarding laid in this manner is termed sheeting, 26 BRICKLAYERS’ GUIDE which is supported by upright poling boards and struts, as shown in Fig. 13. The method of fixing is as fol¬ lows: The earth is taken out to a depth of 9 in., and a pair of boards is inserted and strutted apart; another depth of 9 in. is then taken out, and sheeting fixed as before. This process is repeated until a sufficient number of boards has been inserted, usually four; upright poling boards are then placed in position against the sheeting and strutted apart, as shown in Figs. 9 and 10; the first fixed struts are now struck and cleared away. The above system may be improved upon, when the depth of the cutting is not too great, by cutting the sides of the excavation to a slight batter, as shown in Fig. 14; by so doing tffi timbers are prevented from falling should the earth contract on becoming drained; it also facilitates the fixing of the struts. Large Cuttings. —Contiguous trenches, if made ix bad ground, are generally arranged as shown in Fig. 15. At intervals guide piles are driven in, to which walings are bolted, and sheeting consisting of boards about 10 ft. long, shod with iron, termed runners, inserted between; these are driven a short distance into the ground, the earth between the two systems of piles being then taken out, and care taken not to excavate within a foot of the bottom end of the runners, which are again driven in and the process repeated. After the excavation of the first part, wales, consisting of whole timbers, are placed in position and strutted apart, the struts being also of balk timber. Long struts are supported in the direction of their length by short uprights secured to them by dogs. Uprights are also placed between the waling pieces as each fresh one is inserted. FOUNDATION 27 28 BRICKLAYERS’ GUIDE After the ground has been excavated to the depth of the runners, a fresh system of piles and runners is driver slightly to advance of the former system, and the grouna excavated as before. Cuttings are made in firm ground by excavating the earth and using ordi- Girfcfe P/Zes. 9x9 Fig. 15. nary sheeting, but if the cuttings are required to exceed 30 ft. in width, it is found to be more eco¬ nomical to adopt a system of raking shores. The method illustrated in Figs. 16 and 18 is employed where the ground is soft and waterlogged, FOUNDATION 29 / * 7x// Pc/incj Boards. ~ : ~ | g ■Ji • ' ;3 wujSWm =sji T 1 T 1 *. l v; I yf ' 1 1 > 1 I I ^1 4-x12. Wa//njs. 0 n 9x3 Runners. | Li! 1 i $ t 1 20-d>* 1 ft 1 if / # *-0 | 1 :1 g 1 i jm i §P^-*' 1 Fig 16. 1 1 - - - * ---— - 1 4 I i ^ Wec/gea. 8 1 i * -0 1 i i i < — Pj 1 i 1 j | -:- ! - 1 Fig. 17 : 1 30 BRICKLAYERS’ GUIDE and is especially suitable for running sand. By this method as much of the earth is taken out as is possible without the sides of the excavation falling in, gener¬ ally from 4 to 6 ft.; this is then supported by upright sheeting, waled and strutted. The excavation is con¬ tinued by lining the cutting with a secondary system of runner, i.e., battens 7 x 2 in., pointed at lower ends and of about 9 ft. in length. These are waled and strutted. Between each runner and waling piece a wedge is inserted. The method of proceeding with the excavation is as follows: The wedges securing one runner are loosened, the earth from the foot removed to a depth of about 12 in., the runner being dropped as the ground is removed and re-wedged. Each runner FOUNDATION 31 is successively treated in this manner till the whole system has been lowered the necessary amount. It is essential that the feet of these runners should be at all times kept in the ground, as, if any portion of the vertical side of the excavation be exposed, the earth is liable to ooze out and leave the back of the runners unsupported and cause the whole system to collapse. Sinking Shafts. —It is often necessary to sink shafts for foundations, etc. These are made from 4 ft. square and upwards, the former being the smallest size a man can work in without difficulty. Shafts from 4 to 9 ft. square are timbered as shown in Fig. 19. In ordinary soils the earth is excavated to a depth of at least 3 ft., and in firm soils 6 ft. The sides of the excavation are then lined with vertical sheeting, consisting of boards 9 in. wide, 1 to lyi in. thick, strutted apart by frames of horizontal waling •.timbers, a pair of which is placed in position against two opposite sides, and strutted apart by another pair driven tightly between and against the remaining sides, these being secured by cleats nailed to the fixed waling pieces. Another depth of earth is then taken out and a second system of sheeting placed in, the upper ends of which lap about 1 ft. over the lower ends of the first system of sheeting; another frame is placed in position as be¬ fore, securing both systems of sheeting. Uprights are fixed in the angles between the waling pieces, and often at intermediate positions along their length. This process is repeated till the required depth is obtained. Fig. 19. 32 BRICKLAYERS’ GUIDE The timbering requires to be supported if the depth be great, to prevent it from sliding down on the removal of the earth from its lower end. Where this has to be done, the upper end of the shaft is left projecting about 3 ft. above the ground level. The two first fixed waling timbers at the ground level are continued through the shaft, and project several feet on either side, a good bearing on the solid ground on both sides of the shaft be'ing thus obtained, as shown in Figs. 20 and 20A. x hese members are usually out of square timbers; tney are strutted apart as described. An upright vertical timber is notched over this, and spiked to the face of the waling timbers below, the whole being thus tied together. These are often supplemented by similar timbers at the bottom of the shaft. These timbers are fixed in two pieces, with a scarf in the center; they project about 3 ft. into both sides of the pit. A chain is FOUNDATION 33 sometimes employed in addition to the timber spiked to the walings. Intermediate struts are required to support the horizontal walings where the size of the pit is above 9 ft. square. One system of struts is fixed between two opposite sides, being supported at their ends by cleats, as shown in Figs. 21 and 23; these being necessary to prevent the timbers falling should they become loose Uhriqht bet we e n ^Trafs during the progress of the work. The struts that support the remaining sides intersect by butting,-as shown in Fig. 22, against the first system, and are- therefore fixed in two pieces. The struts at their 34 BRICKLAYERS’ GUIDE intersection are supported by uprights, on the upper ends of which short ends of timber are placed, project¬ ing beyond the sides, acting as corbels, and forming a ledge upon which the shorter struts take a bearing. The earth is raised from the bottom of the shaft, if of a great depth, by means of hoisting tackle; but if the cutting be shallow, stages are often erected in 6 ft. heights, the earth being shoveled from one to the other till the top is reached. Tunneling.— In building operations it is often neces¬ sary to bore a tunnel in order to construct drains, etc., the process being carried out as follows: Tunnels are made just large enough for a man to work in, that is, from 4 to 7 ft. square. The earth is taken out in sections of about 3 ft. at a time, poling boards of the same length being then placed against the upper surface, and kept in their position by a system of strutting, consisting of a head, sill and two up¬ rights, out of either round or sguare timbers. The sill is placed in position first, being partly bedded in ground to prevent lateral motion, and being bedded in its correct vertical position by boning through from the sills previously bedded; the head next, then the struts, which are cut and driven tightly between the two. The next section is then cleared out, commencing at the top, just enough being taken out there to allow of the next system of poling boards being inserted, these being arranged to overlap the first system at their back end, the two being then strutted up together; this process is repeated till the tunnel is finished. If the soil be bad and the sides liable to fall in, they must also be lined by poling boards, these being kept in their place by the uprights. Large spikes, similar in shape to floor brads, are FOUNDATION 35 driven into the head and sill, with their heads left projecting so as to be easily withdrawn, to secure the struts when in position. Wood cleats are often used in place of these. These tunnels are usually made slightly tapering from the base to the head, as shown in Figs. 24 and 25. Foundations. —The construction of foundations varies with the nature and bearing strength of the soil. The following are the ordinary soils met with in practice and the method of treating them: Rock, chalk, gravel, clay and sand. Rock. —Foundations laid upon the solid rock are undoubtedly secure, as far as settlement is concerned; such a substratum being practically incompressible. Rocks often have fissures and defective parts, and all gaps must be filled up with concrete, any unsound parts being cut away. Rock foundations are very expensive in working, owing to the extra labor involved in cutting them; but where they occur they may be built upon direct. Chalk.—The sites for buildings on chalk or marl soil should be drained, and precautions taken to prevent 36 BRICKLAYERS’ GUIDE them becoming wet. Where this can be done, the structure can be built upon the chalk or marl direct, after it has been leveled; but where heavy buildings are erected, or great weights concentrated, concrete should be employed to distribute the pressure. Gravel. —Where lateral movement is not likely to occur, gravel is one of the best soils to build upon; it is not affected by the action of the atmosphere, and is practically incompressible. Clay. —Clay is a good soil to build upon where the foundations are taken deep enough to be beyond the action of the atmosphere. Clay is very subject to expansion and contraction with the variations in tem¬ perature, and is therefore dangerous to build upon unless protected. Sand.—Sand is a good material to build upon, if it can be kept dry and confined laterally; if subjected to the effects of running water it is liable to be scoured from about the foundation. In all the above soils, with the exception of the rock, and the chalk when in a good condition, it is usual to form a bed of concrete, the area of which is proportioned to the weight to be carried and the bear¬ ing strength of the soil. The following are cases that require special treat¬ ment: (i) Soft soils of a great depth; (2) soft soils with hard strata beneath; (3) soils not having a uniform resistance, formed of rocks which have hollows or fissures filled up with some softer material. As this work is intended to be more of an elementary and practical work than otherwise, the foregoing will be quite sufficient on the preparation of trenches, cut¬ tings and excavations for foundations, at least for the present. FOUNDATION 37 In preparing footings on which to lay bricks, care must be taken to keep the work in line and fairly level on top before the brickwork is commenced, whether the lower footings be of stone or of concrete. At this writing, concrete seems to be the popular material in use for the lowest layer of foundation, and justly so, as, when properly put in place, and the proportions of the various materials wisely assigned and mixed, the work will be as though one solid stone was laid all round the building on which the brickwork may be placed. An illustration of the proper method of lay¬ ing in a concrete footing is shown in Fig. 26, and one that has been adopted in many an architect’s office and many a municipal building department. Taking the wall in section and ex¬ tending the concrete each side of the bottom course of footings, drop perpen¬ dicular lines as outside width of concrete, the depth being determined by an angle of 45 degrees, passing from the point A of the next work, and cut- Fig. 26. ting the outside line of concrete. A cubic yard of con¬ crete would require 27 cu. ft. of broken brick, stone or shingle, 9 cu. ft. of sand, 4^ cu. ft. or 3J4 bu. of Port¬ land cement, and 25 gal. of water. These quantities should be correctly measured, turned over together three times dry, and again several times while the water, through a hose, is being sprinkled over the mass. Broken brick or stone small enough to pass through i^-in. mesh is preferable for the aggregate. The practice of throwing in concrete from a height, in 38 BRICKLAYERS’ GUIDE order to consolidate the mass—which used to be con¬ sidered essential, even when staking had to be erected and the stuff wheeled up to the required height at con¬ siderable expense—has now exploded. It should be brought on to the side, deposited and lightly punned or beaten down with wooden rammers, but only just sufficient to bring the moisture to the surface; if rammed too much the cement comes up with the water. If, however, it is more convenient to tip the concrete into an excavation, no sensible injury will be done to it. The objection that, in falling, the heavier particles separate from the finer is, from the very stickiness of the mass, more theoretical than practical, and, at the most, applicable only to each separate barrow load tipped in, and not to the whole bed. Sliding it down a wooden shoot, however, should never be permitted, as the cement and small stuff cling to the sides and run down in a muddy slush; whilst the stones are shot out into a separate heap by themselves. In ordinary foundations the concrete should be deposited in horizontal layers, about 2 ft. thick, and care should be taken to cover any joints in one layer by the suc¬ ceeding one, as the joint between two days’ work is always a weak part; more¬ over, the last layer should be well wetted to insure a proper connection with the next. Fig. 27. Sections of Footings and Walls in English Bond. H B/evofion. Sections of foot/ngs and Watts in Bngtish Bond. V" >'U | I Section of f'e Br/ck Wait Concrete Bo undo t/on Beef/o of 3 Brick W&f/ Fig. 28.' 40 BRICKLAYERS’ GUIDE In Fig. 27 an illustration is shown of a wall and footings, the latter being of stone, not less than 6 in. thick. On the lower footing of stone is laid another course of stonework, and on this is laid the brickwork, the top of the upper stone being made level and a layer of good mortar spread over it so that the bricks have a good bed to rest on. This layer should be cement mortar where possible, as it would help to make the whole work stronger and better. Fig. 28 shows five sections of brick walls and foot¬ ings, with the methods of arranging the bricks in the wall; there being a one, a one and a half, a two, a two and a half, and a three brick wall, showing the pro¬ portions for concrete footings. A scale in feet and inches is shown on the page, so that the proper meas¬ urements may be taken off for actual use. A fact worth considering. All these examples are in English bond, but are good for any other bond. Having dealt with foundations and footings, as we hope, in a satisfactory manner, it will not be out of place to say a few words on damp courses and means of preventing damp from getting up into the walls of buildings. DAMP COURSES In the construction of walls for dwellings, or in fact any other building of importance, it is essential that damp be prevented from being drawn up into the body of the wall by attraction; and the first thing to do in this case is to give some careful consideration to the floors, walls and footings of the cellar. Much has been written on the subject, and many recommenda¬ tions of more or less value made as to the means of its prevention. Whether or not many of these are expe- DAMP COURSES 41 diencies and not cures, the conditions in each case must decide. All building materials, with perhaps the exception of granite, are porous and capable of absorbing and transmitting moisture in large quantity. The damp¬ ness in our dwellings, however, arises from a variety of causes; from absorption of moisture from the soil in or on which the building stands (a clay soil being peculiarly bad in this respect); from imperfect joints at window sills and lintels, as also unfilled and un¬ pointed joints on the face of the wall; from moisture, forced into the walls during heavy driving rain storms; and from the water used in the process of construc¬ tion, in the mortar and plaster, the wetting of brick, etc. Every damp-preventing device, therefore, should be twofold in nature; it should, first, preclude the mois¬ ture from getting into the walls, and second, should not hinder it from getting out of the walls. The former is to be accomplished by an absolutely water¬ proof covering, such as asphalt or tar, or the complete isolation of the wall from any sources of dampness (exception, of course, being made here to the mois¬ ture which is put into the walls in building, and which should be allowed a proper opportunity to dry out). The latter is assured by the perfect ventilation of the walls on all sides. The remedies for the dampness arising from the sev¬ eral causes above noted will be studied in their proper relative places. There are many devices for keeping moisture from entering the cellar walls, and they may be divided into applications to the outside of the wall, and construct¬ ive devices. The efficiency of the former depends, in 42 BRICKLAYERS’ GUIDE large degree, on the care and thoroughness with which they are applied. Of this class we have rock asphalt, tar and cements. The first and second are applied to the wall with a large brush and must, obviously, be i -boiling hot. The coating must be not less than three-eighths of an inch thick, covering every joint, and be carried down to the bottom of the footings. To ensure perfect protec- _ tion, the wall should have been built _____-as carefully as possible, the joints well pointed, the whole to have be¬ come well dried, and the asphalt or tar applied in two or more coats. The coatings should not stop on the Fig. 29. face of the wall, but be carried en¬ tirely over the top, Fig. 29. Some builders recommend that the asphalt be mixed with linseed oil. Concerning cement as a guard against water, opin¬ ions now differ. That it is an excellent protective covering when it is well and thoroughly applied is not to be questioned. It is, however, frequently fractured by the settlement of the walls, and, being to some degree porous, suffers from the action of the frost. In either case it has no further value as a protective. To lay it properly, all the joints and beds of the wall should be raked out at least one-half inch deep. The coating should not be less than one-half inch thick, and should, as far as possible, be applied all at one time. If it is necessary to make a joint it should be vertical and not horizontal. The last precaution is that the earth must not be filled in against it until the cement h« thoroughly set. A similar protective DAMP COURSES 43 covering is made of a concrete of one-half lime mortar and one-half good cement (Portland preferred). Of constructive devices to guard against dampness we have, first, those that are in the wall itself, and comprise the horizontal damp courses, hollow brick lining and facing and hollow wall. The horizontal damp courses are of several kinds, and are placed at the bottom of the wall either on top of the footings or a short distance above them. The most effective course is one of asphalt or tar, Fig. 29, applied in coats in the same manner as described for the facing of the walls. A greater degree of effi¬ ciency is given by laying the course of bricks imme¬ diately above the damp course, while the last coat is still hot and soft. When this damp course is set in a stone wall it would be better to lay a course of bricks and on this place the asphalt course, starting the stone¬ work above the latter, Fig. 30. A layer of slate, set in cement, has been much employed as a damp course. It has, however, the disadvantage of being very liable to fracture under uneven pressure. Sheet lead is a most excellent damp course, .and has been applied to the purpose for two centuries. For ordinary work its cost precludes its use. It is claimed that the penetration of moisture can be hindered by building the wall so that there are no continuous bed joints through the wall. This device 44 BRICKLAYERS’ GUIDE is presented on its own merits, the writer having no personal knowledge of its efficiency. Another excellent damp course is found in the use of perforated terra-cotta bricks. These are made the same size as the ordinary brick, and can, therefore, be readily bended into the wall. A course may be set immediately above the footings and another at or near the top of the wall. The bricks should be laid so that the openings run through the wall and so allow of ventilation and evaporation of any moisture that might Fig. 31. Fig. 32. rise in the hollow bricks themselves, as shown in Fig. 31. The perforated bricks are also used to form a vertical damp course. They may be placed either on the inside or outside of the wall and may be laid as stretchers, as there is not the same liability to collect and retain moisture as there is in the horizontal course. Headers should be placed at frequent intervals to bond the facing to the body of the wall. A simple and somewhat inexpensive system of ren¬ dering walls absolutely damp-proof and of adding very DAMP COURSES 45 much to their strength and stability is to build the brickwork in two4^-in. thicknesses with a ^ or ^-in. cavity kept clear of mortar. Thin boarding is inserted in the cavity as the work advances, the space being afterwards filled with rock asphalt compositions. The compositions answer the double purpose of binding the two thicknesses together and making the wall impervious to moisture. A section of such a wall is shown in Fig. 32. As a rule damp-proof courses should be 6 in. or more above the level of the external ground, but, where possible, under the wall plate carrying the joints for the floor. In buildings fin¬ ished with a para¬ pet wall, a damp- proof course should be inserted just above the flashing of the gut¬ ter, so as to pre¬ vent the wet which falls upon the top of the parapet from soaking down into the woodwork of the roof and into the walls below. In some localities damp-proof courses are formed with slates set in cement; these are rather liable to crack, and thin impervious stones are better. Sheet lead has been used for the same purpose, and is most efficacious, but very expensive. Arches are frequently rendered all over the extrados 46 BRICKLAYERS’ GUIDE with asphalt or cement to prevent the penetration of wet, same as shown in Figs. 33 or 34. In addition to the precaution adopted to prevent damp out of the ground from rising in walls, it is necessary (especially when using inferior bricks or porous stone) to prevent moisture falling upon the outer face from penetrating to the interior of the wall. The wet may be kept out of the interior of the wall by rendering the exterior surface with cement, cover¬ ing it with slates fixed on battens or with glazed tiles set in cement; glazed or enam¬ eled facing brick answer the same purpose. Sometimes ver¬ tical damp courses are used as shown in Figs. 34 and 35, particularly when the ground outside is higher than the wall plate inside, t o prevent the damp penetrating through the wall. It will be seen that the damp course is bedded in the wall directly under the wall plate; this prevents the damp rising and destroying the wood. The verti¬ cal damp course acts in a similar manner in excluding the damp through the side of the wall; the joints of brickwork should be raked out to receive this damp DAMP COURSES 47 course Fig. 35 shows a good method of keeping damp out of the main walls. When the ground level is higher than floor level it will be seen that a 4^-in. wall is carried up to the ground level and covered on top with a stone coping fitted with an iron ventilating grating. 13 y this method, as the damp penetrates through the 4/4-in. outer wall, it rises and passes through the grating and into the open air. This wall is carried about ^/ 2 in. from the face of main wall, and bonded into main wall as shown. Where the bonds enter, the main wall is tarred to prevent any damp wall plate entering. Another method of preventing damp from getting into a wall is to adopt what is known as the “dry area method,” which is simply the building of a dwarf wall all around the building and leaving a space of two or more feet between the dwarf wall and the walls of the building as shown in Fig. 36. It will be seen by sketch that the ground is excavated to a width of 2 ft. from main walls and the dwarf wall built as shown to keep the water away. This area is necessary in damp situ¬ ations, as any moisture or wet is carried away y a drain that is laid under the area, thus keeping the Fig. 35- 48 BRICKLAYERS’ GUIDE main structure dry. The dwarf wall is finished with a brick-on-edge coping built in cement. The floor of area is usually covered with cement concrete paving to prevent the water soaking in. Fig. 33 shows an em closed dry area formed by means of the arch; this area is drained as in Fig. 34, and the moisture is car¬ ried through the flue, as shown by dotted lines, into the open air. This flue is lined either by neat cement or by asphalt to prevent the moisture penetrating into the wall. Hol¬ low or cavity walls should be used for external work in damp situations exposed to driving rains. Such walls are of brick or stone, with a cav¬ ity of 2 or 2 Yz in. The external wall should be in., the thicker portion being inside; false headers being used in the outer wall. The thick wall inside will carry the doors and roofs, the woodwork being kept clear of the outer portion, which is liable to be damp. The cavities should be ventilated by air-bricks in the external portion at top and bottom. Care must be taken that no mortar or other drippings get into them; movable boards or hay bands should be used. The wall ties, generally of cast or wrought iron, gab vanized or well tarred and sanded, should be employed Fig. 36. DAMP COURSES 49 to tie the two walls together; or, better still, a tie or bonding brick, which is made for this pur¬ pose, may be used as shown in P'igs. 37 and 38. Walls constructed after this method not only exclude the damp, but the layer of air they contain, being a non¬ conductor of heat, tends to keep the building warm. Such walls are formed in two separate portions, stand¬ ing vertically parallel to one another, and divided by a space of about 2 to 3 in. There are several ways of arranging the thickness of the portions of the wall, and the consequent position of the air space. In some cases the two portions are of equal thick¬ ness, the air space being in the center, as at Fig. 37. 50 BRICKLAYERS’ GUIDE Very irequently one of the portions is only 4% in. thick, built in brickwork in stretching bond; the other is of such thickness as may be necessary to give the whole stability, as in Fig. 38. In such a case the thin 4^2-in. portion is sometimes placed on the outside, and sometimes on the inner side of the wall. In some cases, such for instance as when the wall has a stone face, the 4^-in. portion is necessarily on the inside, but this arrangement has many disadvan¬ tages. In the first place, the bulk of the wall is still exposed to damp, and the moisture soaks in to within 7 or 8 in. of the interior of the building. Again, if the wall has to carry a roof, expense is caused, as the span should be increased so as to bring the wall plates on to the outer or substantial part of the wall, clear of the 4^-in. lining. This may be avoided by bridging over the air space, so as to make the wall solid at the top, which, how¬ ever, renders it liable to damp in that part. On the other hand, if the 4^-in. portion is placed outside, the damp is at once intercepted by the air space, kept out of the greater portion of the wall, and at a considerable distance from the interior of the building, and the thicker wall then carries the joists, also the whole weight of the roof. The following illustrations, Figs. 39, 40, 41, 42, 43 and 44, show how a hollow wall should be constructed in order to have it substantial and effective. Fig. 39 shows how the angles should be bonded to secure good substantial work, also the position of the air-bricks to secure good ventilation. Fig. 40 shows how to bond the work around fireplace openings, flues and other DAMP COURSES 5i similar work. In Fig. 41, sections of a window and doorway are shown, also an elevation of brickwork with door and doorway in which are shown the posi¬ tions of the metal ties marked by the little crosses. Fig. 42 shows a plan of the doorway bonded with ties. The elevation of wall shown in Fig. 43 illustrates the positions of the ties, also of the air-brick. In Fig. 44 the manner of finishing the top of the wall to take in Fig. 39- the wall plate and rafters is shown quite clearly, also the position of air-brick. In hollow walls care should be taken that the iron ties do not tip inwards, as water will in such case traverse even the double twist usually employed. The better shape has a V drip in the mid¬ dle. To prevent the wet which may enter the air space dripping on the window or door frame, a piece of sheet lead is built in on the inner side of the 4j4-in. exterior 5 2 BRICKLAYERS’ GUIDE wall, \]/i in. turned up and carried about 2 in. farther than the ends of the lintel. There is another method sometimes resorted to because ot its cheapness, and which, in some cases, proves quite effective where the ground is dry or composed of sand or gravel, and that is to lay com¬ mon field tiles or weeping tiles all around the wal's both inside and out- > side and connect ' them by drain tiles to the sewage system or to some low spot, where the drainage will be effective. p If- f t 4b Fire-place Opening. Plans of Bonding round Fire-place Openings. Fig. 40 . ■Cement channel over lintel to fall each way. )-*-p UE , [ 1.1 I XX XX XX oxxx XX XT mm These weeping tiles should be on a level with the foot¬ ings of the building and even lower when possible, to get a good fall so that the water will drain off readily. It will be understood that the dampness of walls is usually owing directly to the absorbent qualities of the DAMP COURSES 53 materials of which they are composed and hence houses built of inferior bricks, which are always absorbent to a considerable extent, cannot be expected to be dry, and especially if they are in isolated posi¬ tions, where the walls are exposed to the full blast of the weather. Even where good materials are em¬ ployed, the same effects may be noticed in exposed buildings. The best construction for a brick building in such positions is the employment of the hollow walls, as shown in the foregoing, which should be carried up throughout the whole of the structure. Their effi¬ ciency depends, as in the case of the area walls, upon Fig. 42. forming a cavity. A damp-proof course should also be provided, and may with advantage be made on the level of the cavity gutter, so as to answer for the two purposes. The few courses of bricks between the damp course and the footings may be built solid, the bricks being cut to form the necessary width. Various ties for connecting the casings are in the market, two of which are represented in the illustrations. That formed of brick is moulded so as to rise a course front to back to prevent the water from creeping along it, and the iron tie is provided with a middle indentation for the same purpose. Properly constructed, these cavity walls are quite 54 BRICKLAYERS’ GUIDE effectual in rendering a building dry. They should always be employed for buildings standing by them¬ selves. Strips of lead, tin, zinc or other metal must be placed over all door and window openings, being bent so as to throw any water falling upon them into the gutter below. Cavity walls cost very little more than solid ones. The quantity of bricks used in the construction is almost the same, the only extra mate¬ rials being the ties and the guttering. Besides keep¬ ing the building dry, hollow walls have the advantage of rendering the interior of the house less affected by Fig- 43 - changes in the temperature, rendering it cooler in the summer and warmer in the winter, a considerable advantage in a variable climate like this. The hollow space, moreover, lends itself very readily for the pur¬ poses of ventilation. Dampness will sometimes be found to arise from the soil below the floor, and in building upon suc.h soils the whole site should be covered in, beneath the low¬ est floor, with dry earth, or, better still, with a thin layer of concrete, which will prevent the damp rising from that source. DAMP COURSES 55 Referring now to the cure of damp buildings, it will nearly always be found to be at the best a troublesome matter. Sometimes the building will have been erected without a damp course, and the insertion of one by underpinning all around the building will, in such cases, generally effect a cure; or it may penetrate through the walls, either in the case of a cellar wall, from the earth resting against it, or from the rain beat¬ ing through in the stories above. In the first case it may be removed by digging away the soil around the building and erecting a dry area wall, such as that before referred to, but as this is always quite an expen¬ sive way a simpler method may be tried. See that the earth around the building is properly graded, construct small air shafts at frequent intervals, inserting air¬ bricks above the ground line so as to place the space beneath the floor in direct communication with the outer air. This may be sufficient of itself, but if the wall is plastered and still shows signs of dampness, proceed as follows: Hack off all the plaster from floor to ceiling. Place a stove in the middle of the room and keep up a large fire, night and day, until the walls feel quite dry to the hand. Then render the walls in plaster composed of nearly neat Portland cement. Many obstinate cases have been cured in this man¬ ner. Re-rendering the plaster is expensive, and various paints and washes are in the market for application to the face of the plaster to keep out the damp. Some of them are effective, but the success of all depends upon the very simple precaution of stripping the whole of the paper from the walls and getting them dry before applying the wash or paint. In some cases the dampness will be found to rise some 2 ft. only from 56 BRICKLAYERS’ GUIDE the ground, and a cure has been attempted by painting the wall or applying lead foil beneath the paper to that height; but the method is useless, for the damp will only rise and show itself above the line of foil or paint. In outside walls dampness will sometimes show itself in small patches here and there, and sometimes in quite large patches. The small patches probably arise from a few bricks of inferior quality which have inad¬ vertently been built in the wall, and a cure can gener¬ ally be brought about by covering the space on the inside of the wall beneath the paper with lead foil, using it to cover a space about 6 in. beyond the actual space of dampness. Where large spaces on the wall show damp, it may arise from defective gutters, from bad bricks, want of pointing, or other causes. Remove the cause, if possible, and if that cannot be done, the following remedy will prove of use. Melt 3 lbs. of strong soap in 4 gal. of water, and carefully apply to the wall, so as not to produce a lather. Mix ^ lb. of alum with 4 gal. of water, allow it to stand for 24 hrs. (by which time the soap will be in a condition to receive it), and carefully apply as before. The following is said to be quite effective in keeping out damp, when properly applied to outside walls: Soft paraffin wax, 2 lbs.; shellac, lb.; powdered resin, y 2 lb.; benzoline spirit, 2 qts,; dissolve these by gentle heat in a water bath, then add 1 gal. of ben¬ zoline spirits and apply warm. The mixture is very inflammable, and must be kept away from the fire. We may mention here another method of making brickwork impervious to water, known as Sylvester’s process, which was used with success on the Croton reservoir, Central Park, New York. It consists in the DAMP COURSES 57 successive application to the walls of two washes, one composed of Castile soap and water, and the other of alum and water. The proportions are y lb. of soap to i gal. of water, and y 2 lb. of alum to 4 gal. of water. The walls should be quite dry and clean, and the temperature of air not below 50 degrees Fahr. The soap wash is laid on first with a flat brush and at a boiling heat. After 24 hrs. the wash becomes dry and hard, and the alum wash is applied at a temperature of 60 to 70 degrees Fahr. This is allowed to re¬ main 24 hrs., when the operation is repeated until the wall has be¬ come impervious to water. The number of applications required will depend on the water pressure to which the wall is subjected. In the Croton reser¬ voir cases, four coatings were found to render the reservoir free from leakage under 40 ft. head. This is similar to the recipe given in another paragraph. Resin has been used also as a protection against mois¬ ture. Five parts of turpentine, heated and stirred in ten parts of pulverized common glue, and one part of finely-sifted sawdust are then applied to the wall, which should be cleansed and heated by means of a lamp, so that the composition may run into every crack and joint. Very often a cement lining is of no use to make a tank water-tight, especially where the" bricks and joints are of an inferior description, and the aim should be to get a composition which, when heated, 58 BRICKLAYERS’ GUIDE enters the pores of the brickwork and renders them - impervious. The top of a wall also may be as likely to admit dampness as the bottom or sides, if it is not properly protected by the roof or by proper copings; as the rain, sleet and snow are liable to soak down into the body of the brickwork and cause damp and decay. Copings may be of a variety of shapes and materials, stone, copper or other sheet metal, terra-cotta tiles, brick or cements. If bricks are employed, good Port¬ land cement mortar should be plastered over it, cover- Fig. 45- ing it at least an inch deep. A number of copings are shown in Fig. 45. The first illustration shows a wall covered with a half-round pressed brick laid in cement mortar. The other illustrations show for themselves. There will often occur cases where it will be expe¬ dient to support loads by the method of brick corbel¬ ing, which consists of one or more courses projecting the required distance from the wall. There are two points that have to be considered in corbeling. The first is, that as every projecting brick is acting as a cantilever the end of the brick should be BRICK CORNICES 59 tailed into the wall as far as possible. To obtain this, as many headers as are available are used. Secondly, the projection of every course over the one below should not exceed 2^ in.; but it is better if it is only 1 }i in. Corbeling renders the walls less stable by bringing the center of gravity of the mass nearer the internal edge of the wall. Figs. 46 and 47 give two examples. Fig. 46. Fig. 47. BRICK CORNICES Brick cornices are carried out on the principles of corbeling, the length of bricks being 9 in. No cornice made entirely of bricks should project more than that amount. This being accepted, bricks are more suit¬ able for the large projecting cornices of buildings treated in the classic styles. Wherever bricks are employed in the latter styles, if the cornice has modillions, the latter are usually of stone of a color resembling the bricks and well tailed into the wall, thus forming a support for the crowning courses, as shown in Fig. 48. Fig. 49 shows the brick backing for a plastered cornice; the large projection is also here obtained by the use of stone. Bricks are more suitable for cornices of buildings of the Gothic styles, 6o BRICKLAYERS’ GUIDE ^r/cft on ec/^e course. F B i i n n fi n rn rn ir n i i i. i i -i. i L l l J i~r~i r ,t:i ,rrm / ——. I . . I ,_l/TVg-la^.J , '," 17 r —,~ r— ;— . 4 —. ,;f,— Oen f/iCourse ikons 3-E-EJ 1 1 ... , EL-- i IS J \ i T T _l-LL-l I I L I .1 . 1.1 -LJ-LJ ...1 J J ., 1 T r Cast / ron Gutter. _ SUU2 IT !i b A witew a \ — >sfc l— -T-CJ #=?4 TTgJz Br/ck on ecute Course _ Piaster Corn/ce with brick <3 stone hacking. ^ Moc/i/hons Obliged 6uc/< Gorn/ce BRICK CORNICES 6l which usually resolve themselves into a moulded band supported by a corbel table, as shown in Figs. 50 to 54. In either variety there is no detriment in placing the bricks on edge wherever the dimensions of the members or disposition of the arts render that arrange¬ ment necessary. Another style of cornice, in which moulded bricks are used, is shown in Figs. 55 and 56. In setting this out, convenient lengths should be taken, e.g., from Fig, 55 - and including pilaster and pilaster, and the whole, or in the case of a long length, the half, or even quarter, should be laid out upon plan, breaking round project¬ ing keys, etc., the setting out pricked over for headers and stretchers, or, if the projection be too great, then for headers only, so as to get an exact number without broken bond. It may occur that the headers and stretchers are slightly over or under 4^ and 9 in.; but, whatever the size, a gauge is cut to it, and the headers and stretchers reduced to the gauge. The bricks 62 BRICKLAYERS’ GUIDE should be joggled, and the work properly run in with Portland cement. All internal miters, stopped returns, etc., in cornices should be solid. Some brick cutters make cut miters, putting them together dry, as being an easier method; but this is not correct work. It will be noticed in Fig. 55 that the cornice is con¬ tinued round, and forms a cap to the pilaster; the prin¬ cipal perpends in the plain work of this and of the general face work being continued through the cornice as far as possible. The breaking out of the returns -T - 1 1 ' 1 ' r —r -1- 1 — 1 r it l 1 n 2 I 'll.., t 3 J_► 17 .lt : LI Fig. 56- round the pilaster and the bonding between the latter and the straight run of cornice is made out where necessary in between. Thus taking course 1 of the cornice in elevation, Fig. 55, the brick A pairs with the plain brick B, which goes home to the pilaster. If A did the same, then a joint would occur imme¬ diately over the angle of the pilaster, and the return would appear as if it were merely stuck on, which would be unsightly; hence, to remove the joint from this point, A becomes a bat header, and a solid return is obtained in the three-quarter bat C, which, on account of projection, as will be seen upon plan, is made out by a brick shellacked to the back of it. As already stated, it is sometimes necessary for headers only to be used in cornices. This applies with greater force to the top course, where they aie frequently BRICK CORNICES 63 beveled to form a weathering. The bonding of the courses 1, 2, 3 and 4 upon elevation agrees with those marked 1, 2, 3 and 4 upon plan. (See Fig. 56.) In making plain pilasters and cutting and setting them out, but little more skill is required than that of gauging bricks for a Gothic arch, unless they be fluted or seeded, or both; then a pair of moulds cut to the plan of the pilaster should be used; the brick being worked in the box face upwards, the back of the brick on the bottom of the box being roughly squared. The difficulty lies in setting out the proper bonding of the base and cap. The full-size plan and elevation of each should be worked in con¬ junction with a few courses of the plain work; the bond accurately set out, and the work cut according — 3 J. 2 -- ITJ Fig. 58. to it (see Figs. 58 and 59, which represent the eleva¬ tion and plan respectively of the base). Here it will be noticed that the bonding of the plain work of the pilaster and also the general face work is kept as far as possible, courses 1, 2, 3 of the elevation agreeing with 1, 2, 3 of the plan. The cap of the pilaster is taken in conjunction with cornices. Pilasters vary in shape upon plan, and the correct 64 BRICKLAYERS' GUIDE bonding must be dealt with as the cases occur; but an instance is given in Figs. 60 and 61 of a half-octagonal pilaster, and in Figs. 62 and 63 of a half-hexagonal. It frequently happens that the bricklayer has to panel a wall under windows, in gables and other similar places, and in order that the workman may be Fig. 59- prepared for such work the following has been selected which gives a few instructions on the subject, and which will be found simple and easy to follow: In setting out panels, the height is usually kept in courses with the general work; but the width is not always the multiple of a 9-in. stretcher, and needs consideration. Set up a quarter of the panel, what- r^i Fig. 61. Fig. 62. Fig. 63. ever the width, including the moulding, and prick over for headers and stretchers. Let Fig. 64 be a quarter of a panel, measuring 4 ft. in width. Had the width been 3 ft. 9 in., it is very clear that five 9-in. stretchers would exactly fill it; but, as it is 3 in. over ihis, divide the 3 in. equally among the five stretchers, making them slightly over 9 in., and the headers and closers in proportion. The joints will be arranged as in Fig. 64; the mould for the side stretchers, e.g., BRICK CORNICES 65 A B, etc., will be as in Fig. 65, one side of the brick being roughly squared and placed on the bed of the box; thus the brick will be worked on edge with the moulding upwards; the moulds for the top and bot¬ tom horizontal moulding being as in Fig. 66, and worked with the roughly squared bed of the brick on the bottom of the box, the moulding again being upwards. The side headers C D, etc., will require another pair of moulds (Fig. 67), the brick being placed in the box on edge and moulded on the end. Mould for side stretchers. Mould for top and bottom courses. Fig. 65. Fig. 66. All angles should be cut in the solid brick, with no mortar joint. A projecting key is sometimes adopted in an arch as an ornamental feature, when some few of the center bricks, including the key-brick and those adjacent, are made to stand out from the general face of the arch; 66 BRICKLAYERS’ GUIDE sometimes being also moulded (Fig. 68). Whatever size the block may be at the top, it is divided into odd courses; thus 8 in., in., etc., would make three courses, 14 in. five courses, etc., the course being cut to the same template as those for the rest of the arch, though, if necessary, to a different cutting mark. If the projecting key is also to be moulded on the face, as Fig. 68, the bricks are first cut to the template, the depth and thickness being properly arranged and bonded (Fig. 68 and 69, which show one course in definite and the other in dotted lines), then set, or “blocked” as it is practically known, together with white lead and shellac, and after- Mould for side headers. Fig. 67 . Fig. 68. Fig. 69. wards cut in the box, face upwards, in the same way as ordinary mouldings. There are many other difficult and interesting details in ornamental brickwork, which it is hoped will be treated upon in some future work. BONDING 67 BONDING The question of “bond” is one of the most impor¬ tant in brickwork, yet few bricklayers give much atten¬ tion to this department of this work. They generally follow certain rules customary in the locality in which they reside, or methods they learned during their apprenticeship. Bond (that is, to bind) is the name given to any arrangement of bricks in which no vertical joint of one course is exactly over the one in the next course above or below it, and having the greatest possible amount of lap. Bond in brickwork is the method of arranging each brick so that it laps over the bricks with which it is in contact above and below a distance equal to one- quarter of the length of the brick. To ensure good bond the following rules should be rigidly adhered to: First, the arrangement of the bricks must be uniform, and as few bats as possible be employed; second, a closer to be inserted after the quoin header in any course; third, the vertical joints in every other course to be perpendicularly in line on the internal as well as the external face; fourth, stretchers are only to be used on the faces of the wall, the interior to consist of headers only, except in footings and corbels; fifth, the dimensions of bricks should be such that, when bedded, the length should equal twice the width plus a mortar joint. Hindrances to good bond often occur when facing or pressed bricks used are costly or of different lengths and widths to the body of the wall; in 9-in. walls, where it is necessary to have two fair faces, very frequently facing both on the outside and inside. 68 BRICKLAYERS’ GUIDE Figs. 69-79. Examples of English Bond. BONDING 69 There are several kinds of bond used in brickwork, among which we may name: first, English; second, double Flemish; third, single Flemish; fourth, Eng¬ lish cross; fifth, Dutch; sixth, stretching or chimney; seventh, heading bond; eighth, country or garden- wall bond; ninth, raking bonds; tenth, hoop-iron bond. When the bond is arranged as shown in eleva¬ tion and plan Figs. 69^ to 79, it is known as English bond, and sometimes old English bond. It consists of one course of headers and one course of stretchers alternately. In this bond, bricks are laid as stretchers only on the boundaries, of course, thus showing on the face of the wall, and no attempt should be made to break the joints in a course running through from back to front of a wall. That course which consists of stretchers on the face is known as a stretching, course, and all in course above or below it would be headers with the exception of the closer brick, which is always placed next to the quoin header to complete the bond, and these courses would be called heading courses. It may be noticed that in walls, the thickness of which is a multiple of a whole brick, the same course will show either: (a) Stretchers in front elevation and stretchers in back elevation. (b) Headers in front elevation and headers in back elevation; but in walls in which the thickness is an odd number of half bricks the same course will show either: (a) Stretcher in front elevation and header in back elevation. ( b ) Header in front elevation and stretcher in back elevation. In setting out the plan of a course to any width, 70 BRICKLAYERS’ GUIDE Double Flemish Bond. \ i 1 1 l ' 1 l IJ i .~ r ~ r . i - ' I i i~r~m Elevation of Wall. Fig. 80. ?. 5 Quod Fig. 8i. End Fig. 82. Fig. 84. Fig. 85. Fig. 86. L Fig. 83. Fig. 87. Fig. 88. Fig. 89. -1- 1 ■ Fig. 80-90. Examples of Double Flemish Bond 1-1 Fig. 90. BONDING 7* draw the quoin or corner brick; then next to the face (which in front elevation shows headers) place closers to the required thickness of the wall, after which set out all the front headers, and if the thickness is a multiple of a whole brick, set out headers in rear; the intervening space, if any, is always filled in with headers. Double Flemish bond has headers and stretchers alternately in the same course, both in front and back elevations, as shown in Figs. 80 to 90. It is weaker than English bond, owing to the greater number of bats and stretchers, but is considered by some to look better on the face. It is also economical, as it admits of a greater number of bats being used, so that any bricks broken in transit may be utilized. By using double Flemish bond for walls one brick in thickness, it is easier to obtain a fair face on both sides than with English bond. Single Flemish bond consists in arranging the bricks as Flemish bond on the face, and English bond as backing. This is often done on the presumption that the strength of the English bond as well as the external appearance of the double Flemish is attained, but this is questionable. It is generally used where more expensive bricks are specified for facing. The thin¬ nest wall where this method can be introduced is 1% brick thick. Plans of alternate courses are given (Figs. 91 to 99). The front elevations are the same as in double Flemish bond. English Cross Bond. —A class of English bond. Every other stretching course has a header placed next the quoin stretcher, and the- heading course has closers placed in the usual manner (Fig. 100). Dutch Bond. —In every alternate stretching course a 72 BRICKLAYERS’ GUIDE Fig. 91. Single Flemish' Bond. Elevation of Wall Fig- 97 - Fig. 93 Fig. 99. Figs. 91-99. Examples of Single Flemish Bond. BONDING 73 header is introduced as the second brick from the quoin; three-quarter bricks are used in the remaining stretching courses at the quoins, and the closers are dispensed with in the heading courses, as shown in Figs, ioi to 105; the longitudinal tie becomes much greater, and the appearance of the elevation is cer¬ tainly superior to much of the inferior work one is accustomed to see as examples of the modern brick¬ layer’s skill in bonding. Should there be a fracture, it is supposed to throw it more obliquely. Stretching bond should be used only for walls half brick thick, as for partition walls. All bricks are laid as stretchers upon the face. Garden or boundary-wall bond, country bond, Scotch bond, are the names given to walls built with three stretchers and one header in same course, constantly recurring, as shown in elevation, Fig. 106. This method is used for walls one brick thick that are seen on both sides, as it is easier to adjust the back face by decreasing the number of headers, the lengths of which usually vary. Heading bond is used when circular corners have to be turned, as in Figs. 108 and 109. It is evident that stretchers, unless it be upon a large curve, would be too long for this purpose. In walls built of material in which it is impossible to get a bond, two or three courses of brickwork are fre¬ quently introduced to act as a tie or bond; these are termed lacvig courses. Again, in big arches, consisting of 4^-in. brick wings, lacing courses are sometimes used to give additional strength, as in Fig. no. Hoop-iron Bond. —An additional longitudinal tie termed “hoop-iron bond” is often inserted in walls, being usually pieces of hoop-iron I in. x * n -» one Fig. 100. EDt/fch £3'one/ Fig. i of. I !" J-u -A © - C o — -U-J UJ L L r :i i i i i T-rT rnrr E/evafion on Return Elevation I o 5 Figs. 100-107. BONDING 75 row for every half brick in the thickness; should be carefully tarred and sanded or galvanized before using, to prevent oxidation. It is hooked at all angles and junctions. If bedded in two courses in cement, additional strength is gained; pieces of hoop-iron may be used with advantage where the bond at any part of the wall is defective. Raking Bonds.—Walls as they increase in thickness increase in transverse strength, but become proportion¬ ally weaker in a longitudinal direc¬ tion, owing to the fact that stretchers are not placed in the interior of a wall. This defect is remedied by using raking courses at regular intervals of from four to eight courses in the height of a wall. The joints of bricks laid in this position cannot coincide with the joints of the ordinary course directly above or below, the inclination of the face usually being determined by making the extremi¬ ties of the diagonal of two, three or more bricks coin¬ cide with the backs of the facing bricks. It is not advisable to use one raking course directly above another, as there is always a weakness with the face bricks at the junction of the raking. Raking bonds are always placed in the stretching 76 BRICKLAYERS’ GUIDE courses in walls of an even number of half bricks in thickness, in order that their influence may extend over a greater area than would be the case if they were placed in the heading courses. The alternate courses of raking bonds should be laid in different directions, in order to make the tie as perfect as possible. There are two varie¬ ties of raking bonds, viz., diagonal and her¬ ring-bone. Diagonal Bond. —This is used in the thinner walls, i. e., between two and four bricks in thickness. The operation is as follows: The face bricks are laid; one or more bricks (in the latter case placed end to end) are bedded between the face bricks, so that the opposite corners touch the latter; this determines the angle that the bricks should be laid, the triangular spaces at the ends of the bricks being filled up with small pieces of brick cut to shape, as shown in Fig. 111. Herring-Bone Bond.— The bricks in this method are laid at an angle of 45 degrees, commencing at the center line and working towards the face bricks. Herring-bone bond is used for walls four bricks and upwards in thickness. Fig. 112 shows this method. 1 \X\X\ Fig. 112. B A \ \ / \ \ 1 A A/ A A 1 C x / \ V m \ /\ \ \ ! \ / \ \ \ 1 / A / / \ / \ 1 / ✓ \/ \/ \X \/I C/ X X X X 1 \ Fig. hi. BONDING 77 Figs. 113-120 Junctions of Cross Walls. ?8 BRICKLAYERS’ GUIDE Diagonal and herring-bone patterns are often used to form ornamental panels in the face of walls, and also in floors paved with bricks. Junction of Cross Walls. —The bond is obtained in cross or party walls abutting against main walls by plac¬ ing a closer 4j£ in. from the face in every alternate course in the main wall, thus leaving a space 2 ]^ in. deep and of a length equal to the thickness of the cross wall for the reception of the I J^-in. projection in every other course of the cross wall, as shown in Figs. 113 to 118. Figs. 119 and 120 illustrate the junction of one-and- a-half brick Flemish bond with one brick English bond. Reveals. —The vertical sides of window or door open¬ ings between the face of wall and window or door frames. The horizontal distance between is the clear span of opening. Jams are the vertical sides of an opening, and in rebated window or door openings there are the internal jambs and external jambs, the latter being known as the reveals. Internal jambs are usually covered with plaster, or wood linings. Figs 121 to 131 show brick reveals, with rebated jambs in English bond. Splayed Jambs. —The internal jambs of windows occurring in thick walls are often splayed to obstruct as little light as possible. Figs. 132 to 142 show the method of bonding two alternate courses of a three- brick wall, built in single Flemish bond. In inferior work splayed jambs are often formed by simply con¬ structing a number of square offsets. Squint Quoins. —External angles other than a right angle in plan are called squint quoins. Such require BONDING 79 Fig. 121. Fig. 122. Fig. 125. Fig. 126. Fig. 129. Br/ck Bevea/s w/fh rebafed □ jambs /n Eng/tsh Bond. Fig. 123. Fig. 124. □ Fig. 127. Beves/ ■ Figs. 121-131. Brick Reveals with rebated jambs in English Bond., 8o BRICKLAYERS’ GUIDE considerable care in the planning, as different angles require special modifications of the principles of bonding. Two general rules should be kept in view, viz.: (i) no bird’s mouth joint in plan should be employed, except on the face of the work in acute angular quoins, where it is at times absolutely necessary. They would be useful in the interior in some cases, but sufficient care is not usually taken in cutting the re-entering angle where the brick is not exposed to view, the latter generally becoming cracked or broken, as bricks do not lend themselves to be easily cut in this manner. (2) All small pieces should be avoided, the bricks being as nearly as possible whole, and only having sufficient cut off to adapt them to the plan. Closers are not always necessary in obtuse angles; better work is pro¬ duced where they can be superseded. It is evident that the quoin stretcher can never show its full length on either face. Advantage should therefore be taken, if the angle is not too great, to show three-quarters of a brick at the quoin, as shown in Figs. 137 and 138, thus obviating the necessity of a closer to gain the proper 2^-in. bond; but in acute angles, the quoin stretcher can always be obtained in its full length, as shown in Figs. 139 and 140. Figs. 132 to 136 show the method of constructing squint piers, such as would be employed in the angles of bay windows. Toothing. —The usual method of leaving a brick wall which is to be continued at some future time is to tooth it, which consists in leaving each header project¬ ing 2% in. beyond the stretching courses above and below to allow the new work to be bonded to the old as shown in Fig. 144. BONDING 81 Fig 132 fig. ^33- Figs. 132—142. 82 BRICKLAYERS’ GUIDE The usual practice in joining new cross walls to old main walls is to cut out a number of rectangular recesses in the main walls equal in width to the width of the cross wall, three courses in height, and half a brick in depth; a space of three courses being left between the sinkings (as shown in Fig. 143); the new cross wall is then bonded into the recesses with cement mortar to avoid any settlement. It is necessary that the sinking should not be less than 9 in. apart, as in the cutting the portion between is likely to become shaken and cracked. Racking.— Racking is the term applied to the method of arranging the edge of a brick wall, part of which is unavoidably delayed while the remainder is carried up. The unfinished edge must not be built vertically or simply toothed, but should be set back 2^ in. at each course, to reduce the possibility and the unsightliness of defects caused by any settlement that may take place in the most recently built portion of the wall. Also where new walls are erected the usual method of procedure is to build what is technically termed a corner—that is, the angles or the extremities of the walls—to a height of two or three feet, the angle bricks being carefully plumbed on both faces. The base of the corner is extended along the wall, and is racked back as the work is carried up, as shown in Fig. 145. The intermediate portion of the wall is then built between the two corners, the bricks in the courses being kept level and straight by building their upper edges to a line strained between the two corners. Leveling of Brickwork. —In bedding bricks, great care should be taken to keep all courses perfectly level. To do this, the footings and the starting course should be carefully, leveled through, using a level at BONDING F«g- M3- new 84 BRICKLAYERS’ GUIDE least io ft. in length, commencing at one end and leveling towards the other, and taking care to reverse the level each time at each forward step, and com¬ pleting the length to be leveled in an even number of steps. A piece of slate or iron is left projecting from the lowest course, and from this all other courses at the corners can be leveled by using the gauged rod, which is usually about io ft. in length, with the courses marked on it. The work should then be again tested by the level, and the operation repeated. Joints.—Bricks and stones are bedded with mortal for two purposes, viz., to cause the bricks to adhere to each other, and to distribute the pressure uniformly over the whole bed where the beds of the bricks or stones are irregular. Great care should be taken that both the bed and side joints are thoroughly flushed, or filled up with mortar. This is done in three ways: i, by the trowel; 2, by larrying; 3, by grouting. The first method is that usually adopted in thin walls. The second, larrying, is largely adopted in thick walls. The face bricks are first laid; the mortar, in a semi¬ fluid condition, is then poured into the space between the face bricks; the bricks are then pushed rapidly horizontally for a short distance into their position; a certain amount of the mortar is thus displaced; this rises in the side joints, and completely fills all the interstices; should the mortar not rise to the top of the joints, the vacant spaces are filled up when the next course is larried. (3) Grouting is an operation used in brickwork, generally for gauged arches and similar work, where fine joints are required; it consists in mixing the mortar to a fluid condition, of about the consistency of cream, this being poured into the joints of the work after the latter has been placed in position. BONDING 85 Joints on Face. —The joints on the face of work are finished in a variety of ways, as shown in Figs. 146, A to L, to increase the effect, and to resist the weather; they may be finished as the work proceeds, or as the scaffold is taken down on the completion of the build¬ ing; the former is the stronger and more durable, the latter is cleaner and has a better appearance, and is rendered necessary when the work has been built during frosty weather; where the latter method is employed, the joints should be raked out for at least yi in. in depth as the work proceeds. The joints in new work should be clean, sharp and regu¬ lar; but no fancy pointing is permissible. Fig. 146, A to L, shows the forms of joints applied to brick¬ work. Flat or Flush Joints.— This is formed (as shown in Fig. 146, A) as the work proceeds by pressing with the trowel the wet mortar that protrudes beyond the face, flat and flush with the wall. Flat Joint Jointed. —This is formed similarly to the above (as shown in Fig. 146, B), but has, in addition to the previous joint, a semicircular groove run along the center of each joint, with a jointing tool and straight-edge. This has the effect of making the mortar more dense. /V 1/ Fig. 146 a to l. 86 BRICKLAYERS’ GUIDE Struck Joints. —This is formed by pressing with the trowel the mortar along the upper edge of the joint slightly below the surface, as shown in Fig. 146, C. This is a good joint, as the upper edge of the mortar is protected, and any water is thrown off with facility; its appearance is good, as it presents a sharp shadow at every horizontal joint, and forms the method of finish¬ ing new work; it is sometimes called a weather-struck joint. The mortar is often ignorantly struck back on the lower edge, as shown in Fig. 146, D, under the impression that the appearance is enhanced thereby, the idea being that a sharp line is presented on the upper edge of the bricks, but as no shadow is formed the effect is lost at a few feet above the eye; a ledge is formed on which the water lodges, which freezes in the winter, and rapidly destroys the upper edges of the bricks and the joint. Keyed Joint, as shown in Fig. 146, E, is formed by drawing a jointing tool with a curved edge, the same width as the joint, along the latter; it has the effect of making the mortar dense at this part, and improves the appearance by making the joints distinct. It is not much used. Keyed joints of the form shown in Figs. 146, G and H, are employed where the wall is to be rendered. In the first ca-se, the mortar in the joints is left protrud¬ ing; in the second, it is raked out. Recessed Joint. —This is used to obtain a pleasing and deep shadow, but care must be taken that the bricks are hard and unlikely to be damaged by the weather. It is the joint employed in many of our best buildings. Fig. 146, F, gives this joint. Pointing Old Works. —This operation consists in rak¬ ing out the decayed mortar from the joints to a depth BONDING 8 7 of at least % in. and in filling the same with cement, or some hard-setting mortar, as shown in Fig. 146, I. The joints may be finished in any of the methods stated, or by one of the two methods known as tuck and bastard tuck pointing, which are fancy forms adopted by bricklayers to increase the effect by form¬ ing sharply defined joints. Tuck pointing, as shown in Fig. 146, J, consists in filling up the raked-out joints flush with a stopping of cement or some hard mortar. The joints in this con¬ dition generally appear very wide, owing to the edges • of the bricks being ragged, this being due to the frost or to the clumsy method in which the joints have been raked. The whole front, joints included, is then col¬ ored with a compound of copperas and a pigment of the color required, or the front is rubbed with a piece of soft brick till the bricks and the joints are of one color. While lime putty is pressed on to the joints in straight lines, with a jointer worked on a beveled edge straight¬ edge, and before the latter is removed, the edges are trimmed with a tool called a Frenchman, which usually consists of an ordinary table knife with the end of the blade turned up at right angles to the remainder. The edge of the knife cuts the putty, and the turned-up end drags off the superfluous stuff, leaving a white joint in width and ^-in. in thickness on the face of the work. This is not the best method of pointing if the bricks are sound and their edges sharp and regular; but if the edges are broken, the joints, when stopped, appear very wide and irregular, and are thought by some not to look well if the above pro¬ cess were not adopted. This method should never be permitted. Bastard Tuck Pointing is the name given when a 88 BRICKLAYERS’ GUIDE ridge % in. to yi in. is formed on and off the stopping itself, as shown in Fig. 146, K. Masons’ V Joint, Fig. 146, L, shows the usual joint used for masons’ work. CHIMNEY BREASTS, FLUES, ETC. These have to be formed according to the design of the house; but in most cases, for the sake of economy in space, etc., the fireplaces are built, one over the other, from floor to floor, and frequently in party walls, the latter being the wall which divides house from house. The openings will differ in size, according to the range or grate used. For example, a full sized range would require an opening 4 ft. wide and 1 ft. ioj 4 in. deep; the extra depth, beyond what is required for the flue, being lost when the flue is in position by arranging a set-off in the breast to form a mantel-shelf. For an ordinary register stove the opening would be 3 ft. wide by 12 in. deep, and so on, and, unless provision be made by a breast breaking out upon the outside of a building, a projection or breast must be formed inside the rooms to receive the stoves and provide for the flues. The back of the fireplace should not be less than 9 in. in thickness; therefore the projection of the breast depends upon the thick¬ ness of the main wall and style of stove to be used. That is to say, if the depth of the fireplace be 1 ft. 1 ^ in., then in an 18-in. wall with a 9-in. back to fireplace, the breast would project 4^ in ; in a 14-in. wall, 9 in., etc. It is most desirable to have as much bend as possible in flues; not to have the flues larger than is necessary (a kitchen flue should be 14 x 9 in., an ordinary living room 9x9 in.); to gather in quickly above the arch, Fig. 147 . Fig. 14 s. 90 BRICKLAYERS’ GUIDE though not so quickly as to form a nearly flat surface immediately above the fire; and to have perfectly easy bends, with no abrupt angles. For a flue to success¬ fully do its work, smoke should be treated as though it were water. Sharp turns and breaks interrupt the I 1 1 = riimu-p L 1 I Fig. 149. Fig. 150. easy flow of the smoke, causing it to eddy round, choke the flue, and return again to the room. The inside should be smoothly rendered with pargeting, i.e., cowdung and lime, in the proportion of 3 to 1. ■ffi nnc » 1 i I Fig. 151. Fig. 152. This makes a smooth surface, is tough and is supposed to prevent the smoke stains and heat from coming through the wall. Ordinary mortar, however, is now more often used than pargeting. Fig. 147 is the sec¬ tional elevation of fireplaces over each other, as far as is possible, in a double- breasted wall; Fig. 148 being a cross- section taken through the double breast; Figs. 149, 150, 151 and 152 are plans of the same on the basement, ground, first and second floors; while Fig. 153 is a plan through the stack. Chimneys and flues may be constructed at any angle- on condition that any flue inclined at an angle less than 45 degrees is provided with suitable soot doors. Mistakes are often made in constructing flues CHIMNEY BREASTS, FLUES, ETC. 91 * through not carrying them fast enough to the right or left, as the case may be, so as to prepare for the fire¬ place above; then, when the mistake is discovered, they are carried over quickly, and a flat surface is formed, resulting in a faulty flue. To obviate this, an easy calculation should be made as soon as the flue is gathered over and brought into position above the fireplace. Taking Fig. 147 as an instance, the flue being in position 2 in. above the arch, measure the height to the fireplace above, and the distance the flue has to be taken to the right or the left; or, in other words, ascertain how many inches it has to be taken laterally to the foot vertically. In the case in point, F is the flue in position in the middle of a 6-ft. 4-in. breast. The distance to the fireplace above is 6 ft. and the 9-in. flue has to be carried to the right, allow¬ ing 4^ in. outside work. Then it is evident that the left side of the flue has to be carried a distance of 2 ft. in 6 in. or 24 in. in twenty-four courses, to get into position; that is to say, the flue must recede on the under side, and sail over on the upper, 1 in. in every course. Fireplace Jambs. —When starting the fireplace in the basement, the jambs on each side will be solid, and are usually 14 in. on the face by the depth as already described. The flue, being taken either to the right or to the left, will appear upon the next floor as a jamb 18 in. on the face. This allows 4^ in. outside work, and a 9-in. flue. If, however, the flue should be 14 x 9 in., then the jamb will be 23 in. on the face. As already stated, fireplaces vary from 2 ft. 6 in. to 4 ft. in width, according to the stove to be used; and they will also vary in height, that for a kitchen being 4 ft., ^nd for an ordinary register 3 ft. high. When 92 BRICKLAYERS’ GUIDE the proper height is attained, an iron chimney bar is placed in position. This slightly curved bar (Fig. 154) is 3 in. wide, % in. thick, and rests 4^ in. each end upon the jambs, the ends also being split and turned half up and half down into the brick¬ work. An arch of two or three half¬ brick rings is then carried over upon Fig. 154. the chimney bar, and the work con¬ tinued above it (Fig. 155). Instead of the iron bar, lintels of coke breeze and cement, or an arch turned on a temporary turning piece, is now frequently used. Mode of Carrying the Hearth. —The hearth should be at least 18 in. wide, and extend beyond the fireplace opening 6 in. each way. There are several methods of supporting the hearth, but the most usual is by means of the trimmer arch. Turning pieces are fixed in between and at right angles to the trimmer T and the breast B (Fig. 156), covered with thin lagging, seen in section in the last named figure; the arch, con¬ sisting of rows of stretchers on edge and parallel to the breast, is then carried over and properly keyed in (see Fig. 157, which is a horizontal section taken CHIMNEY BREASTS, FLUES, ETC. 93 through the fireplace, and showing the trimmer arch on plan). Another good system is that of tee-irons with the table turned downwards, fixed in between the trimmer and breast, sheeted with temporary boarding underneath, and filled in with concrete. Fig. 158 is a longitudinal section taken through such a hearth. Or the tee-irons may be fixed as already described, but kept such a distance apart as to allow a plain tile to be placed in between two adjacent webs lengthwise. Three courses of these tiles should then be laid and properly bonded in Portland cement and sand. Fig. 159 is a cross-sec¬ tion illustrating the latter system. In each ' system the surfaces are brought to with concrete to within y.i in. of the under Fig. 157. side of the hearth, the in. being allowed for bedding. The back hearth, when there has been no breast below, will be treated in the same way as the front, but in all other cases will be bedded on the brickwork. Every flue should be complete in itself, for if open¬ ing be left in the 4^-in. walls—or withes, as they are termed—which part flue from flue, the smoke will enter the flue not in use, and a down current will take it into the room. Coring-holes 12x9 in. should be left, and temporary boards fixed in each flue and upon each floor, for the 94 BRICKLAYERS’ GUIDE purpose of clearing out the rubbish that may fall down the flue during the building. Corbeling. —If it should be necessary to increase the width of the breast, this may be done by corbeling the brickwork between the floor and the ceiling. By sailing over in. per course on each side for three courses, the breast may be increased 9 in. (Fig. 147, A A). When anything beyond this is required, then stone corbels should be used. If the fireplace jambs are not carried up from the basement upon solid foun¬ dations, but grow out from the party wall, as it were, by means of corbeling, then the breast may project the thickness of the wall upon which it depends. Hard stone corbels are really more reliable than brick corbeling for this purpose. When the chimney breast has taken in all the fire¬ places and flues required, and appears above the top¬ most ceiling, the flues are brought into the position in which it is desired they shall be seen when above the roof. This, when out of sight, is done by dropping off the superfluous brickwork in offsets. But when the breast appears as a projection upon the outside of the building, then one method of reducing it is that shown in Fig. 160. Bond in Chimney Stacks. —Though it is far preferable to have 9-in. outside work to chimney stacks, to keep out both the rain and the cold, which retard the even CHIMNEY BREASTS, FLUES, ETC 95 flow of the smoke, yet it is more often that the outside work is 4 y 2 in. only. In bonding stacks, the desired end to be kept in view is that the withes or partings shall be tied in, so as to strengthen what might other¬ wise be a very weak construction. When the flues are surrounded with 9-in. work, either English or Flemish bond may be adopted. Figs. 161 and 162 are plans of alternate courses of the first, and Figs. 163 and 164 of the latter. It is with 4j4-in. work outside that the great difficulty occurs, and up to the present a broken kind of bond, called chimney bond, in which the withes are indifferently tied in, has been used. In this bond a whole stretcher is used upon the quoin; but by sacrificing the small amount, if any, of extra strength derived from the use of the stretcher upon the quoin, and substituting a three-quarter bat in the stretching course, instead of using a closer in the heading course, the work may be built either in English or Flemish, and a perfect tie and bond be secured. (See Figs, no and III for plans of alternate courses of English, and Figs. 112 and 113 for the same in Flemish bond.) According to some strict building acts, chimney shaft or smoke flue shall be carried up to a height of 96 BRICKLAYERS’ GUIDE not less than 3 ft. above the roof, flat, or gutter adjoin¬ ing thereto, measured at the highest point in the line of junction with such roof, flat or gutter. And the highest six courses of every chimney stack or shaft shall be built in cement. Setting Ranges.—Built in and close fire ranges are many and varied in description; but there are general rules for guidance in setting them that are applica¬ ble to nearly all. Double-oven ranges are of course the largest, and the American or self-setting range the smallest. With the latter but little skill is re¬ quired, while the setting of the former is somewhat difficult. To proceed to set a range, the first necessary opera¬ tions are to properly level in a hearth or course of brickwork to take the oven cases; to tempo¬ rarily place the range in position so as to mark the flues, etc., and to build in beneath each oven case suffi¬ cient brickwork to allow a 2-in. cavity below the oven. It will be found that the heat from the furnace traverses the top of the oven, and is then induced to descend on the outside or end of the range to the front of the check, which is a piece of sheet iron fixed diagonally on the bot¬ tom of the oven, and coming from the back extreme corner to within 4 in. of the front of the soot door in Fig. 163. Fig. 162. CHIMNEY BREASTS, FLUES, ETC. 97 the face of the bottom of the range, and centrally beneath the oven door. The flue at the end should cover as much surface as possible, and should not exceed 2 in. wide by the length of the side of the oven, the object being to keep the heated air and gas as close to the oven and over as wide a surface as possible. It has been described how the flue is formed to the front of the check; it is then allowed to go to the center of the back at the bottom of the oven, and from that point is taken up in a flue usually 9 in. or 10 in. wide and 3 in. to 4 in. deep, which ascends vertically to the damper, which is placed at the top of the back coving. The covings are sheets of paneled cast iron that encase the recess above the top plate, the covings, in their turn, being 1 1 1 1 1 I T — 1111 rm 1 1_1_1_LJ_1_ Fig. 165. ICE 1 1 1 1 1 T~ nz 1111 1 HZ ET 1 hi Fig. 166. covered with a top plate. They are usually fitted with a plate rack, and should be bedded with mortar against the insides of the jambs and the brickwork at the back which is formed between the flues. The boiler is set on a benching of fire-brick built at the back of the ash pan and is usually arranged with a flue from the bottom of the furnace to the back of the 98 BRICKLAYERS’ GUIDE range, and a vertical flue formed in a similar manner to the oven flue up to a damper placed at the top of the back coving. The boiler, which should be of wrought iron, is drilled and tapped for the connecting of the hot-water circulation. These are general methods, but special kitcheners often require different treatment. In every case there should be no sharp turns in the flues, and the top flues should be carried above the dampers in the direction of the chimney flue above. Fig. 167. Fig. 168. Register, Mantel Register, and Interior Stoves. —The main object in fixing these is to fill up with brickwork the space which, in the fireplace opening, is not occu¬ pied by the stove or flue. In some cases the register is placed in position, and set by filling in the brick¬ work through the register flap which forms the entrance to the flue for the smoke. These are often insuffi¬ ciently filled up, thereby leaving a large cold-air space at the top, which causes the smoke to be checked and sent back into the room, instead of pursuing its proper course up the flue. For interior grates with fire-lump backs, the shape of the back of the lump should be marked out upon the hearth, and brickwork built up to the shape, allow¬ ing for a mortar bed at the back of the lump. Here, again, it is important that the opening should be filled up as much as possible, leaving only the size of the flue. ARCHES AND GAUGED WORK 99 ARCHES AND GAUGED WORK* Gauged work consists in rubbing and cutting to any- required shape specially made bricks, or “rubbers,” as they are technically termed. This class of work is usually done in what is called a cutting shed, provided with a bench about 2 ft. 3 in. high and 2 ft. 6 in. wide. The tools and appliances required are a rubbing stone, circular in shape, and 14 in. in diameter; a bow saw fitted with twisted annealed wire No. 18 gauge, parallel file 16 in. long, small tin scrib¬ ing saw, square, bevel, straight pieces of gas barrel for hollows in mouldings, etc., bedding slate to try the work for accuracy, straight-edge, compass, setting trowel, putty box (Fig. 169), boaster, club hammer, and scotch (the three latter for axed work), reducing boxes for thickness (Fig. 170), and for length (Fig. 171), moulding boxes (Fig. 172), boxes with radial sides for obtain¬ ing the wedge-shaped voussoir according to the template (Fig. 172)4), a setting-out board about 6x5 ft. and lining paper 2 ft. 6 in. wide, etc. The most elementary kind of gauged work is that ♦This department is largely taken from H. W. Richards’ work on “Brick-laying and Brick-cutting.” Fig. 170. 100 BRICKLAYERS’ GUIDE which is known as plain ashlar, consisting of heading and stretching courses for plain facing. The opera¬ tions are as follows: first bed the brick, i.e., place the brick with the letter or hollow side on the rubbing stone; then, holding the brick with both hands, rub it upon the stone, giving it a circular motion from right to left, and trying it occasionally with a straight-edge till the bed of the brick has become a perfect plane. Next, with the rubbed bed turned from the body, place the side or face of the brick upon the stone, and rub as be¬ fore, at the same time endeavoring to make the side square with the bed, testing it by application of the square, stock to the side, and the blade to the bed of the brick. Then serve the head in the same way, making it square with both bed and face. After these operations are per¬ fect, the brick has to be reduced to thick¬ ness; this is done by placing it on its bed in a reducing box (Fig. 170), the measurement of the inside depth of which is T Vin. under 3 in., sawing off the superfluous material and finishing with a file. If for a stretcher, next place the brick face down¬ wards in a 9-in. lengthening box (Fig. 171), making the square end to coincide with the front edge A of the box, and saw off to length, finishing with a file at ARCHES AND GAUGED WORK IOI the back edge B. The cut stretcher will be 9 in. less 3*2 in. in length. In preparing long headers, the brick would have to be placed in the same box, face downwards, but the saw and file would be used along the top edge of the box, thus making the header <\ l / 2 in. less 3*3 in. in width. If for bat head¬ ers, then the % 1 Fig. 172j£. squared end is placed downwards in the box, and saw and file used along the top edge again. Arches. —These may be plain, axed or gauged. In plain or rough arches the bricks are not cut at all; the joints alone give the radia¬ tion, and the arch is usually made up of rings. The Relieving Arch.— The relieving or dis¬ charging arch (Fig. 173), as its name implies, is used for the purpose of relieving the weight from any portion of the building which is too weak to bear it, and dis¬ charging or transmit¬ A R C B ting it to piers, etc., specially prepared to receive the load. They are sometimes used in the face of build- 102 BRICKLAYERS’ GUIDE ings, when they are also treated as ornamental features. The most frequent use for the relieving arch is inside the building, over door and window openings. The opening is first bridged by the lintel, which should rest not less than 4^ in. upon the jambs each side of the opening; next a brick core is built throughout the entire length of the lintel, to serve as a turning piece for the arch; the curve being obtained by means of a curved mould having the same rise it is intended to give the arch. This is applied to the face of the core; the bricks are marked, and then cut to shape. A skewback, which should radiate from the striking point, is built at each end of the lintel; and the arch, consisting of 4^-in. brick rings, but starting with a stretcher at- each end upon the skewback, is then turned over the core. When a flat rise only is given, the brick core is done away with, and the curve is worked upon the lintel. It must not be forgotten that the lintel is in length the exact span of the arch; that the object of the lintel is for the purpose of fixing the joinery; that the core acts only as a turning piece for the arch, and to fill up the space between this and the lintel; and that neither of them influences the strength of the discharg¬ ing arch in any way. Should a fire occur, the lintel would burn and the core fall, but the arch ought to remain intact. The method of striking out the arch will be the same as that given for the segment. When arranging the rings, those starting from the top and working downwards alternately should always have a key-brick; the other rings will key in with a joint. As already stated, in this as in all other rough arches, the bricks themselves are square, and the radiation is obtained by means of the joint. The ARCHES AND GAUGED WORK 103 mode of drawing the radial joint is as follows: prick over the 3-in. courses and fill in the face from the radial point R, as in the semi-arch. Through the radial point, and parallel with the lintel, draw an indefinite line A B; make one of the courses or bricks of the arch parallel, by keeping the top equal to the bottom of the brick; produce the line which does this so that it cuts the line A B, in C, then C will be the point by means of which a line drawn from it through the soffit end of the face joint of each course will give the radial joint. This method must be followed each side of the arch. The Invert Arch. —It often occurs that the principal loads in buildings, such as girders carrying the floors, etc., are concen¬ trated upon cer¬ tain points, as piers, for instance, which are usually strengthened to Should there be openings r II czz Fig. 174. receive them, upon each or one side only of the pier, it is very evi¬ dent that the weight of the pier and its load would be taken vertically downward to one part of the footings only, little able, perhaps, to bear it. To relieve the special part of some of the weight, by spreading it over a larger area of foot¬ ings, invert arches are used, as in Fig. 174. Here IS Template brick Fig. 174 / 4 - 104 BRICKLAYERS’ GUIDE some of the weight is taken from the pier A and its fellow, and transmitted, by the invert arch, to the footings in between them. It will be noticed that the lines from the radial point to the skewbacks form an angle of 45 degrees, this being found to be the best angle to receive the weight. Chimney breasts in basement stories are often treated in this manner. Egg Shaped Sewer (Fig. 175). —This sewer; as its name indicates, is shaped like an egg, with the smaller end downwards, this shape being found the best adapted for the varied charge of sewage. It matters little whether it be during a time of storm water, or during a dry season, when there is but small quantity of sewage, there is always a sufficient depth of mat¬ ter to ensure a perfect flow. The sewer may consist of two or three 4}4-in. rings of brickwork, with a terra cotta or hard-brick invert; bedded in concrete. The mode of setting it out is as follows: Let AB be the diame' ter of the head, or crown, then CB will be the radius, and C the radial point; measuring out from the center C to the left and right of A and B, a distance equal to AB, will give the radial points D and E, from which the curves of the sides may be described; then, for the invert, draw from the point C at right angles to AB a line CF equal to AB. By dividing CF into four parts, the radial point G will be found. The termination of the sides x , x , and the beginning of the invert is determined by lines passing from D and E through G. The 4^-in. rings will be arranged ARCHES AND GAUGED WORK 105 as in the relieving arch, the outer rings having the key bricks, one at the crown, the line FC passing through the center; and what might be termed two keys, one on each “1 side, the line DE passing through their centers; the next ring towards the inside having straight joints at these points; the next inner ring, keys, and so on. Axed Arches.— Axed arches are really roughly cut gauged arches with t?t -in. m- rnortar, stead of a jV-in. putty joint. There¬ fore, the mode of obtaining the tem¬ plate and the system adopted for gauged arches generally, ap¬ plies equally well to axed ones; the only difference being that when the bricks are hard, the brick will Fig. 177. have to be scribed each side to the template and across the soffit with a tin scribing saw, and cut off to the scribed lines with a boaster (sometimes called bolster) and ciub hammer upon the banker, and the remaining io6 BRICKLAYERS’ GUIDE material between the scribed and boastered lines neatly axed off with a scotch (sometimes termed scutch). In arches in which the end or soffit may not be cut to a bevel, such as glazed bricks, etc., the mode of apply¬ ing the template to the face of the brick is somewhat different. It would simplify the matter, perhaps, if, after the template was obtained, as described, the bot¬ tom of the template were to be cut off to the cutting mark, and made to fit the soffit line of the drawing of the arch and then applied to the face of the brick, the brick and template both being on end, and both the bed and back of the brick cut off to the template. That is to say, both edges of the template would be cutting edges (Fig. 174 ) 4 , which shows the template in position for cutting the brick). Gauged Arches. —Throughout this work one principle is adopted for setting out and obtaining the templates for all gauged arches, and by careful attention to the instructions given, all practical men should be able to gain a perfect mastery of the subject. Whenever the compass is mentioned, it will be understood that in full-size work the radius rod would be used, and although, when describing the construction, the whole of the arch is alluded to, a half only is drawn, as would be the case when setting out in practice. The Semicircular Arch. —This arch is known always as the semi (Fig. 176), the opening here being, 3 ft., the face 9 in., and the soffit 4 ]/ 2 in. Construction , etc.: Draw an indefinite base line; upon and perpendicular to it erect a center line; upon the base line set out the opening AB, half each side of the center line; then with the point of the compass at the c^” 4 C, and the pencil at B, describe the ARCHES AND GAUGED WORK 107 larger half of the soffit, or intrados, and with the point still at C, but the pencil extended 9 in. beyond B, describe the outer line or extrados. In most rubber bricks the brick and joint together will hold out or measure 3 in. Therefore take a distance of 3 in. in the dividers, and starting with half the distance each side of the center line on the extrados, prick over till the courses come home exactly to the springing line, increasing or decreasing the dis¬ tance taken in the dividers, i.e., making it slightly over or under 3 in.; but always taking care that the first- pricking, or key-prick, shall be equally divided half each side of the center line. Call these first two prickings D and E. From the center C, through D and E, draw the approx i mate key, but pro¬ ducing the line through E to H. This approx i mate key will also be the shape of the trial template. To obtain the template the following pieces are necessary: two small straight-edges i6x2x ^ in., and also a piece of board 14 x 334 x ^ in., with both sides io8 BRICKLAYERS’ GUIDE planed and one edge shot square and true. Place the latter, which may be termed F, Fig. 176, with the shot edge against the line radiating from C to D, and with a long straight-edge having the end of one edge against the radial point C, and the other end coinciding with the produced line H, and lay¬ ing over F, mark the latter the shape required. Having cut and shot the template to the line drawn upon it and square with the face* (when it will appear as F, Fig. 176^), pro¬ ceed to traverse it; i.e., see that in pricking over there are fourteen courses in half the arch, including the key; ascertain whether fourteen such templates Fig. 182. Fig. 183. will exactly fill half the arch, starting with the key and terminating with its edge upon the springing line. The way to traverse the template is as follows: Place the template upon the approximate key, taking care that it exactly E F draw a line, will be the as across the left-hand edge immediately over the soffit two straight-edges O and X and tight up to the template, always keeping O fills it; pencil C which known filling-in mark, of the template and line. Next place the one upon each side of ARCHES AND GAUGED WORK 109 little above the filling-in mark, Fig. 176^. Keep X firmly in its place, remove the template, slide O against X, remove X, place the template against, with the filling-in mark on the soffit line; place X against it, remove the template, slide O against X; and repeating this movement till the right-hand edge of the template comes out to the springing line. Should the template at the last turn be parallel to the springing line, but not quite home to it, bring the tem¬ plate down a little by placing the filling-in mark higher up. The top may come over the springing line, and the bottom reach or not quite reach home; then a shaving or two must be taken off the top, or if the bot¬ tom comes over, then a few shavings off this. Each time it becomes necessary to alter the filling-in mark or the template itself, it will be necessary to traverse again, taking care always, at the start, that the tem¬ plate is equally divided, half each side of the center line. When the template has been obtained, line in the joints of the arch with it. The next important matter is to allow for joint. This is done by placing the edge of the template against the radial line CD, backing it up with the straight-edge O kept firmly in position; then, by sliding the template up against the latter, it will recede from the radial line CE. If for axed work the template may be worked up till it leaves the radial line CE by T 3 g- in.; if for gauged work, by in.; then, in a similar way to that in which it was marked for filling in, scribe for cutting mark imme¬ diately over the soffit line, Fig. 176, S. When for gauged work, to prove that the amount allowed for the joint is correct, traverse the template again, with the cutting mark on the soffit line, for four courses, when, if it leaves the fourth line by in., it may be taken iio BRICKLAYERS’ GUIDE as correct. In this arch the lengths of all the courses are alike, and may be taken on the edge of the tem¬ plate, bearing the cutting work; this edge being termed the cutting side of the template, and the other the bed, coinciding in this respect with the arch-brick itself. Place the bed of the template against the radial E, with the cutting mark upon the soffit line, then on the cutting side make a mark on the edge immediately over the extrados (these marks should always be squared across). While the template is in this position, the bottom and top bevels B may also be obtained, by making similar squared lines on the bed of the template, and then connecting these on the face, as in Fig. 177^. In using the template, the soffit bevel will be taken off by placing the blade of the bevel or shift stock against the bed of the template, the blade pointing towards the soffit and agreeing with the line upon the face of the template. It is advisable to write the size of the opening, the name of the arch, and the number of courses upon the template, and also to apply the center (Fig. 178), upon which the arch will be turned, to the striking out, ticking off the courses upon it, and squaring them through; this will act as a guide to keep the proper thickness of joint when setting the work. The setting out should be on lining paper, which may be saved for future reference. How to Cut a Semi-Arch.— Bed the brick and square the face; square the head from the face, but bevel it from the bed, the stock being placed against the bed, and the blade to the head. These bricks must be pre¬ pared for right and left hand; that is to say, with the face of the brick turned towards the body, half the beds should point towards the right and half towards ARCHES AND GAUGED WORK Xu) the left. Then prepare a radiating box io in. wide in the clear, and rather longer than the template, the sides of which, worked from a square line across the bottom, radiate exactly as the template, Fig. 173, also having the cutting mark upon each side exactly oppo¬ site each other. Great care must be taken that the box is accurate, and it is advisable to try the first radb ated brick upon the bedding slate, with the original template. Two bricks, right and left hand, may be placed in the radiating box, with their faces to the sides and their sofifits to the cutting marks, and sawn close to the top edges of the sides of the box (the lat¬ ter being protected with tin), and finished with the file, taking care to file away from the front arris of side of the box, so that the former may be perfectly sharp; then, in a lengthening box (Fig. 171), facedown- wards, and with the soffit placed tight against a straight-edge held across the end, cut off to a length of 9 in. If the arch is more than 9 in. on the face, then, before radiating, the course must be made up in length. Taking an arch 12 in. deep on the face, as an instance, and dealing with a course having a stretcher towards the soffit, the stretcher will be cut off 8 in. in length, and the opposite - bevel obtained in the length¬ ening box. A bat over 4 in. in length, bedded, faced and beveled, will be fitted to the top of this, the tem¬ plate applied, the brick scribed to the length of the cutting side, and to the square mark on the bed, the twc marks cn the brick connected by the scribing saw, and sawn off square with the face. By this means the course is cut off to length, and the top bevel obtained at the same time. It may here be noted that the 9-in. lengthening box 112 BRICKLAYERS’ GUIDE can be used for any odd measurements, by nailing a stop or fillet across the bottom of the box and parallel to one squared end, according to the length required, the worked end of the brick being placed against the stop, and the piece not required cut off to the end of the box. For an arch having a 9-in. soffit, it will be readily understood that a face stretcher would have to be taken to a depth of 4^ in. in a reducing box and backed up with a properly squared and beveled bat, and that for a soffit stretcher the brick would be bedded, the face beveled for the soffit, and the header, acting as the face, squared from the bed and soffit. By placing this brick soffit downwards in a reducing box 4^ in. deep, the opposite bevel, after sawing, would be worked upon it; being afterwards made out, on the face, by a bedded, squared, and beveled bat, and cut off to length, to the template. Every arch should be keyed in with a stretcher towards the soffit; and it will be found that, counting the courses in half the arch, and including the key, if there be an odd number, then there will be a stretcher, for the start or upon the skewback, and a stretcher for the key; if an even number, then a header for the start, and a stretcher for the key. Arch with Moulded Soffit. —In arches with moulded soffits, although the end in view, with respect to bevels, etc., is the same, the mode of working is some¬ what different. The section of the mould required must be cut upon two boards, 10 x 4^ x y 2 in., screwed together, the edges shot and squared, and the moulding cut upon them while thus fixed, so that they shall be exactly similar; the edges representing the face and soffit may be protected by tin, and they ARCHES AND GAUGED WORK ii3 should be fastened one on each side, exactly opposite each other, to a box having a stout bottom and two sides only, and being about 10 in. in the clear after the moulds are fixed (Fig. 172), the bricks being properly bedded and roughly squared upon the side which is not intended to be the face. The bevel is taken from the template in the usual manner, and marked upon the bottom of the box, both right and left, with the back of the stock against the front edge of the box and the hind part of the blade on the bottom; the roughly squared edge of the brick between the roughly squared face and the bed is fixed against the line or lines thus marked (if there be room, two bricks at a time may be cut, one for right hand and one for left); the saw is taken through the moulded soffit and the top face, and then with file, barrel, etc., the brick is finished, being beveled, moulded and faced at the same time. When the brick is taken out of the box, should the soffit, or face, be not quite true, the bed is rubbed to fit them , the square and bevel being used for tnis purpose. The remaining operations are the same as in plain- gauged arches. Setting. —The center, Fig. 178, having been fixed with folding wedges beneath it, so as to make it easy of careful removal after the arch is set, should be tested for accuracy. Axed arches are set in fine mortar, the joint being either struck, or raked out, and afterwards pointed, to give it a fancied resemblance to gauged work. Gauged arches and gauged work generally are set in lime putty, as already described. The putty is served to the setter in a putty tub. This is a box open at the top and with beveled sides, being about 15 x 12 in. at the top, but smaller at the bottom, and about 9 in. BRICKLAYERS’ GUIDE 114 deep (Fig. 169). The setter, keeping the putty fre¬ quently stirred, and having knocked and brushed the dust off the brick, holds it lightly on the top of the putty, takes up just sufficient to form the joint, removes a small quantity from the center, makes the joint true at the edges, puts the brick in position, and lightly taps it to make it solid. Arches are started from the right and left hand, and worked up towards the key, which is put in last. When the arch is completed in its place, it is grouted in with Portland cement, a joggle having been formed in the brick by cutting a groove 1 x % in. in the middle of it; this grouting in with Portland cement greatly strengthens the arch. In years past, a bead was formed with the joint, and the work left. But now, any irregularity in the face, mouldings, etc., is corrected by means of files, pieces of barrel, brick, handstone, etc., both brick and joint being left flush and brushed down with a soft brush. The Segment Arch (Fig. 177^).—Opening, 3 ft.; rise, 6 in.; face, 12 in. Draw an indefinite base line, and at right angles to it above and below draw an indefinite center line. Upon the base line set out the opening AB half each side of the center line CD, and above the base line measure off the 6-in. rise in E; then with the point of the compasses at A, and taking any dis¬ tance greater than half AE, describe arcs above and below the base line; with the same distance in the com¬ passes and the point at E, cut these arcs in X. Then a line being drawn through these intersections and meeting the center line, will give the radial point O. With the point of the compasses at O, and the pen¬ cil extended to A, describe the soffit, passing through E and terminating at B. Next with the straight-edge at O and passing through A, draw the skewback or ARCHES AND GAUGED WORK “5 abutment, and the same with B; then measure up from the soffit upon the center line 12 in., and with the point of the compasses at O, and the pencil extended to the 12 in., draw the extrados terminating at the skewbacks. Now proceed as in the semi to procure the template, with this exception, that the work termi¬ nates on the skewback, and not on the springing line. Having procured the template, fill in the arch. The courses will be divided into 8-in. stretchers and 4-in. headers, taking care to key in with an 8-in. stretcher towards the soffit. This arch having a skewback, care should be exercised that this is properly cut and set, especially if it be in ordinary building bricks. A mould or gun, as it is termed, should be taken off the drawing and ap¬ plied to the reveal; the projecting or tri¬ angular portion an¬ swering to the fall of the skewback (Fig. 177^). Here A being placed against the reveal, the skewback is built up to B. In this, as also in the semi-arch, if the student wishes to draw the arch only, then the extrados may be pricked over at 3 in. as already described, and the face joints filled in from the radial point by means of a straight-edge passing from it to the divisions on the extrados. Moulded Segment. —When a moulding is worked upon the reveal and continued round the soffit of the seg¬ ment, a new difficulty presents itself in the intersection ii6 BRICKLAYERS GUIDE of the mouldings between these two. Again, take a 3*ft. opening, 6-in. rise, 12-in. face, with a 2^-in. moulding, the half being shown (Fig. 179). Set out the soffit and reveal as in the plain gauged segment; then to the right of the reveal line measure off the depth of the moulding 2^ in., draw the outside moulding line parallel to the reveal line, and continue above the base line. Then on the center line and above the soffit again measure off the 2^-in. moulding, and with the point of the compasses at O and the pencil extended to the 2^-in., describe the moulding line parallel to the soffit, and meeting the reveal moulding in point F. From the point F to B draw a line. This will be the miter line. The skewback will be taken, as before, from the point O, but will begin at the point F. The arch will be cut precisely in the same way as the moulded semi, with a slight addition to the top course of the moulded reveal and the first course of the arch, i.e., where the intersection takes place. Two pieces of board, 10 x 3 x ^ in., should be planed and shot while screwed together, so that they shall be perfectly true in themselves and to each other; the lines H and I will be produced each way and the moulds laid to coincide with the bricks S, Fig. 180; then by means of the straight-edge, which is made to coincide with the produced lines as shown, the lines H and I will be accurately drawn upon the moulds. They should then be cut to this shape, and are known as shoe moulds. A moulded brick, being placed on its bed in between two shoe moulds, can, by means of the saw and file, be properly mitered as M, Fig. 179; the moulded end of No. 1 course of the arch should be then cut to tightly fit it. All other operations for the moulded segment will be the same as in the moulded semi. ARCHES AND GAUGED WORK ii 7 In axed arches with field-moulded bricks (bricks having the moulding cast upon them in the brick-mould while in the green state, and afterwards burnt), such as bull-nosed and mopstaff beaded, the treatment of the miter will be nearly the same, only, that instead of the miter being solid, as in M, Fig. 179, the portion BF in the latter figure will be cut upon the top of the brick, and the skewback taken from that, Fig. 181. Camber Arch. —This is sometimes called a straight arch; but it has really a slight rise, the rule being to give the soffit a rise of } 4 -in. for every foot of opening. The reason for giving the rise is to counteract the optical illusion which causes the arch, if straight upon the soffit, to appear to sag, or camber, the wrong way. When a slight rise is given, the arch appears * Fig. 186. to be straight upon the soffit. It would be impossible to strike such a slight sweep with a radius rod; the rise is there¬ fore given by means of the camber slip. A camber slip should be made of good hard wood that will not shrink or twist; mahogany or oak is excellent for this purpose. It is always convenient to keep one in stock, and if it be long enough it will answer for any opening. There are not many camber arches over 7 ft.; therefore a convenient length for the camber slip would be about 8 ft. The mode of obtaining the camber slip is as follows (an extreme case is given, as being easier of illustration): Suppose the opening to 118 BRICKLAYERS’ GUIDE be 3 ft., and the rise I in. to the foot, then the camber slip 3 ft. long would have a rise of 3 in.; take a rod 3 ft. long, measuring in width 1 in. at each end and in the middle 2 x / 2 in., or in other words, having in the center half the required rise; shoot this piece from the middle to the two ends perfectly straight, thus form¬ ing two triangles, as it were, upon a common base; call the center B, and the two outside points A and C (see Fig. 182). Then take a piece of board a little over 3 ft. long and 6 % in. wide by y 2 in. thick, planed both sides, and one edge shot, draw a center line upon the face of it, and 18 in. each side of it draw two other lines; call the center line E, and the two outside lines D and F, Fig. 183. Upon the center E, 6 in. up from the shot edge, drive in a pin, and upon D and F, 3 in. up from the shot edge, drive in other pins. Then take the first piece, Fig. 182, already prepared, and with a pencil held at the center B, apply it to pin F, and with A on the same piece pressed against the pin E, move the piece with the pencil from F to E, describ¬ ing half the curve, Fig. 184. Repeat this process on the other side, moving the center B with the pencil from D to E, and the curve will be drawn; then cut the curved side to the line drawn, and the camber slip will be completed. To prove the camber slip, lay it down and mark all round it, then reverse it, and if the camber slip coincides with the lines drawn by it, it will be correct. In using the camber slip always work from a center line. The next consideration is what amount of skewback should be given to the camber arch. By the old sys¬ tem the opening was taken as a radius and a line cut upon the center line as a radial point for the skewback; but this has been found to give too great a skewback ARCHES AND GAUGED WORK 119 and becomes a source of weakness. The proof of this ;s as follows: First considered as a wedge, sustaining a vertical thrust or load. If a wedge were made too flat, when driven home the ends would become bruised and split. Again, let it be supposed that the camber arch is taken out of the segment, or let it be consid¬ ered that behind each camber there is an invisible seg¬ ment; then, as far as strength is concerned, the more of the segment contained in the camber, the stronger the arch; experience shows that the longer the radius, the less the rise, or the flatter the segment, and hence the more of it in the camber The less acute skew- back, if produced to meet a center line, will give the desired longer radius. Therefore a good datum to work to, as a general rule, is to give each skewback 1 in. fall for every foot of opening, when the arch is a foot upon the face. To Set Out the Arch. —Opening, 3 ft.; face, 14 in., Fig. 185. Draw the usual base line, with a center line perpendicular to it; set out the opening AB, half each side of the center line CF. Then, with the center of the camber slip upon the center line, and the edge just coming out at the points A and B, draw the camber or curved line. Then to obtain the skewback. At A and B erect faint perpendiculars, and upon these lines measure, from the base line upwards, distances of 12 in. and 14 in.; take square lines to the left of A and right of B, and upon these lines at the 12-in. height measure off 3 in., the allowance for an arch 12-in. face and 3-ft. opening; then from A and B, through the outer points of the 3-in. lines draw the skewbacks indefinitely. These skewbacks would answer for any depth of face for this size opening. Now take a point upon the 120 BRICKLAYERS’ GUIDE center line, 14 in. up from the base line, place the center of the camber slip upon this point, the curved edge at the same time passing through the two 14-in. points upon the perpendiculars erected at A and B, and while in this position draw the outer or extrados line. Prick over the courses upon this line, as in other arches, starting with the key and working out to the skewback. If it were possible to produce the skew- back downwards to meet the center line, then this point might be treated as the radius point wherewith to fill in the approximate key. But should this not be practicable, the number of courses taken upon the extrados line, by reducing the distance taken in the dividers, will have to be pricked over on the intrados line, taking care, at the same time, to have an equal proportion on each side of the center line. Having pricked over the top and bottom lines accurately, draw in the approximate key, but producing the line to the right of the center line, both above and below the arch. Call this produced line DE. Now, to procure the approximate template; as before, prepare a piece of ^j-in. board, 3^ in. wide and 18 in. long, both sides planed and one edge shot. Let the shot edge be exactly placed against the left-hand line forming the key, and, with a long straight-edge placed over the board, the edge coinciding with the produced line DE, mark the template. Cut and shoot it accurately, and traverse as before. Having obtained the tem¬ plate, fill in the courses, and fix the cutting mark. It has already been seen that in the semi and segment the courses have been equal in length, and the bevels alike, but in the camber the bevel and length will differ in each course; the longer bevel and length being in No. 1, and the shorter in the key. An illus- ARCHES AND GAUGED WORK 121 tration of the treatment'of No. i course will serve for all the courses. No. i course is the first course upon the skewback. Place the template with its bed side upon the right-hand skewback line, and the cutting mark upon the camber line. Then, where the edges of the template touch the camber lines, both top and bot¬ tom and on both edges make pencil marks. One mark (the cutting mark, it will be remembered) is already made. Square these marks upon the edges, and con¬ nect the two top and the two bottom across the face of the template; this will give the length of the course upon the cutting edge, and the bevels both bottom and top. Serve each course in the same way, and number their bevels upon the template. The arch is 14 in. on the face; it will therefore be filled in as 8-in. stretcher, 2-in. closer, and 4-in. header, in one course, and 4-in., 2-in., and 8 in., in the next, and so on, as before, key¬ ing in with a stretcher towards the soffit. The skew- back will be treated as in the segment, and all other operations in setting, etc., will be the same. Great care should be taken in grouting in this arch, as it is one of the weakest in construction. It must be remembered, in cutting this arch, that the different bevels have to be taken off and marked “right” and “left,” upon the bottom of the box, as was done in the case of the one bevel in the segment arch. Moulded Camber (Fig. 186).—The moulded camber should be treated similarly to the moulded segment, the outside line of moulding being drawn in with the camber slip, parallel to the soffit, meeting the outside line of moulding on the reveal and forming the miter. The skewback must be taken extra to the moulding, or, in other words, it must be drawn from the outside 122 BRICKLAYERS’ GUIDE point of the miter, so that if a 2%-m. moulding be used in a 3-ft. opening, with an arch 12 in. on the face, the top point of the skewback would fall in. away from the reveal. The shoe mould, etc., would be obtained as in the segment arch. Camber on Circle. —Arches circular on plan are not to be recommended, as being of weak construction. But where it becomes necessary to use them, they should be strengthened by means of an iron bar bent to the shape. The mode of setting out this arch and obtaining the template is very simple. Let Fig. 187 be the plan of the sweep to be covered by a camber arch, of which AB and CD are the outer and inner faces respectively. Develop AB by pricking it over with compasses, or bending a thin lath round the curve and bringing it out as the straight opening EF. Upon EF construct the camber arch in the ordinary way (Fig. 188), and produce the lines of skewbacks, bringing them down indefinitely below the soffit or base line. Next develop the inside line CD of the plan in a similar manner to AB, cutting off its actual length on a rod; then lay the rod in between the skewbacks which are produced below the soffit, till, while keeping it paral¬ lel with the base line, it accurately fills in between the skewback lines. Now, with the rod in this position, draw a line which may be termed a sub-base line, and draw the camber line upon it. Next procure the tem¬ plate as already directed, taking care that it be long enough, not only for the ordinary arch, but also to cover the bottom or sub-camber line. Having got the bevels, cutting mark, etc., while the latter is upon the soffit line proper make another cutting mark also upon the bottom soffit line, and the template will be ready for a camber on circle. ARCHES AND GAUGED WORK 123 When cutting the arch, the upper cutting mark must be used for the face of the arch-brick, while keeping it at the soffit, and the lower cutting mark will be used for the back of the brick, while keeping it in a similar position. By cutting this brick, the student will learn how to prepare the radiating box, one side of which will be higher than the other, according to which side of the arch is being cut. Or, in other words, let it be Fig. 187. granted that the left, or leading hand of the arch, is the one to be radiated. Then, having drawn a square line across the bottom, and parallel to the tail of the box, with the face of the brick turned to the body, and the soffit towards the right hand, prepare the box by placing the upper cutting mark of the template against the body, and the lower one of the other side, to this line. 124 BRICKLAYERS’ GUIDE Should the curve be very sharp, it would cause the arch, if left after the above operations, to appear, on the face, as a series of short lines. To avoid this a pair of moulds io in. long, having the same sweep as the plan of the arch struck upon them, and 4% in. only at their widest point, should be prepared. Each course, being laid in between these moulds according to the angles their beds make with the base line (for instance, the key-brick will lie at right angles between the curved sides), would, when cut, receive the same curve as the plan, Fig. 188. It must be borne in mind, when putting in the skewbacks, that they are radii of the same sweep. Should the face of this or any arch be 18 in. deep, then the bonding will be as in Fig. 190. Fig. 189. Fig. 190. It will be noticed that the skewback of the 12-in. segment, Fig. 179, does not come out to the top of the course, making it necessary to put in a small piece of brick; and again, that the 14-in. camber, Fig. 186, is not in depth the multiple of a brick course, necessitat¬ ing the cutting of an inch course over the arch. To do away with this cutting, arches in these and similar cases may, while maintaining the same bond¬ ing on the face, be increased in depth, care being taken that the proportion between the stretcher, header, and closer is relatively the same. Thus, by ARCHES AND GAUGED WORK 125 dividing the 15 in. in the latter case into seven (the number of closers in a stretcher, header and closer combined), then taking four of these for a stretcher, and two for a header, etc., the stretcher will be found to measure 8f in., the header 4§ in., and the closer 2 \ in. Equilateral or Gothic nrch (Fig. 191).—Opening, 3 ft.; face, 9 in. Draw an indefinite base line, upon it erect a perpendicular center line, and set out the opening AB half each side of it. With the point of the com¬ passes at A, and the pencil at B, draw the curve or half-intrados BC; then with the point at B and pencil at A, draw the other half AC. With the same radius points, and the compasses extended to 3 ft. 9 in., describe the outer line or extrados. When set out properly, this arch, unlike all other arches, has no key-brick, but a joint in the center. It will therefore be necessary, when pricking over, to allow half a course on each side of the center line, as though providing for a key-brick. If lines be drawn from A and B to C, it will be seen that each half of the arch is really a segment, and the template will be obtained in the 126 BRICKLAYERS’ GUIDE same way, only, where the courses meet on the center joint, these extra long bevels thus formed will have to be taken from the drawing and marked on the template. The above is not only the correct method for setting out the Gothic arch, but is also the strongest, as the courses are normals to the curve. But many object to keying, as it is called, with a joint, and insist upon having a key-brick. In the latter case (Fig. 192), the arch has to be set out, as all other arches, starting with half a course each side of the center line, and then pricking over to the springing. The approximate key, which is cut as a bird’s mouth, is then filled in from the center of the base line, and the approximate tem¬ plate obtained and traversed until it is accurate. The courses are then filled in with the latter. Under these new conditions, the courses, not being normals to the curve, will all differ in length and bevel. These will be obtained and marked on the template, in the same way as in the camber (Fig. 185). The Modified Gothic (Fig. 193).—When the equilateral arch has to be reduced in height, by remembering that ARCHES AND GAUGED WORK 127 the two sides are two segments only, the setting out becomes very clear. Again, taking the 3-ft. opening and 9-in. face, set out the base and center lines and the opening AB. Upon the center line set up the reduced height DC; join AC and CB. Bisect AC and CB with lines square to them, and produce to the base line. Where these meet will be the radial points from which to fill in the sides, the template being obtained as in the equilateral arch (Fig. 191). This, like the Gothic arch, may be filled in from the center of the base line, forming a key-brick, the lengths and bevels differing for each course. Lastly, should the curves on AC and CB need modi¬ fying (Fig. 194), these may be brought down by treating them as segmental arches, constructing the base line, and marking the height of the curve upon the center line. Mouldings on these arches are a very simple matter, being treated, when filled in from the radial point, as the segment, and from ihe center, as the camber arch. In neither case is there the difficulty of the miter to meet. The Elliptical Arch. —There is no curve in arch cut¬ ting that requires more care than the ellipse, and there is no arch in which faulty setting out, or a cripple, as it is termed, is more easily detected, especially by the trained eye. First, let it be quite understood that it is impossible to set out the ellipse by means of the com¬ passes, though a very near approach may be obtained, when the rise has not to be taken into consideration, by the following methods: Case 1. Fig. 195; opening 3 ft.; face 9 in.—Lay down the base line with a center line drawn at right angles above and below it indefinitely and the opening AB half each side, as before. Divide the opening AB 128 BRICKLAYERS' GUIDE into four parts in the points C, D, E. With the point of the compasses at C, and the pencil at A, describe an arc; then, with the same distance in the compasses, but with the point A, cut this arc in F. Repeat this on the other side of the opening, and again cutting this arc in F. Through F and C, and F and E, draw lines meet¬ ing at the center line in G, and extended indefinitely above F. Then, with the point of the compasses at G and extended to F, describe the remainder of the curve, or intrados, from F to F. Now, going back to C, and the pencil extended 9 in. beyond A, describe the extrados ter¬ minating at the line FG. Re¬ peat this on the other side of the opening. Then, with the point at G, and the pencil ex¬ tended, draw the topmost part of the extrados. It will not be apparent that in between the lines GF there is a segment arch, the template for which will be obtained as in that arch; and that the other two portions are parts of a semicircular arch, and again the tem¬ plate will be obtained as for the latter arch. This is the sflongest method of filling in, but the appearance of having two distinct shapes of bricks upon the ARCHES AND GAUGED WORK 129 face is certainly objectionable. The difficulty may be overcome by filling in the arch the same as the cam¬ ber, or by pricking over the extrados and filling in from the center of the base line for the approximate key. The bevels and lengths, of course, will differ, but the bricks will be alike on the face (Fig. 196). Case 2. Fig. 197.—Another method of setting out by means of the compasses, with a given rise, the height of the rise bearing a liberal pro¬ portion to the open¬ ing. Set out the 3-ft. opening as before, calling it AB, and the 14-in. rise CD. Join DB; cut off CD from CB in the point d\ take the remain¬ der 55' 5" 10" 9' 2" V V 0 0 ►H 64' 7 " 10" 0" 151 Timesing. —When a dimension occurs several times over, it is written thus— which means that the result of 5 ft. 7 in. x 2 ft. 4 in. is to be multiplied by 2; and looking to rules given, it will be seen that this is 13 ft. x 2, which is 26 ft. Again, a quantity written thus— or dotting on, it is called, means that the result of 5 ft. 7 in. x 2 ft. 4 in. is to be multiplied by 2 added to 3 or 5; and the whole result would be 65 ft. Digging is taken at the yard cube, and depends for price upon the depth, and the distance the earth has to be wheeled or carted. The least amount of depth of trench for a 14-in. wall, including footings and concrete, would be 2 ft. 3 in.; the width being 3 ft. 3 in. Then, taking it that the measurements of digging to trench for a 14-in. wall 20 ft. long are required, the trench itself would be 20 ft. plus (3' 3" — 1' 2") equals 22 ft. 1 in. .x 3 ft. 3 in. x 2 ft. 3 in. The 2 ft. I in. being projection of 152 BRICKLAYERS’ GUIDE footings, concrete, etc., at each end; and the amount of concrete 22 ft. 1 in. x 3 ft. 3 in. x 1 ft. 3 in. These dimensions may be obtained by drawing the plan of the footings and concrete for length and width, and setting up the section for depth, as already shown on page 8. Concrete of less thickness than 12 in. or where under pavings, etc., is taken at per yard super. In brickwork the difficulties of measuring are some¬ what greater. In some places practice is to reduce all work of i)4 bricks thick and upwards to a standard of 272 ft. super bricks thick, which is called a rod; the actual measurements being i6)4 ft. x i6)4 ft. x i }4 in., or 306.2812 cu. ft., reckoned in practice as 306 cu. ft. Walls under this thickness are generally specified with the work they entail, e.g., struck joints both sides, pointed, circular, etc. When measuring foot¬ ings, for instance, multiply the average length by the average thickness, and then by the height. When taking the average thickness, first add the width of the top course to the width of the bottom course in bricks, and divide by 2; thus for a 2-brick wall, 2 plus 42 equals 3. Then the average thickness will be 3 bricks, or 2 ft. 3 in. (When the bottom course is doubled, take one of these courses separately, and afterwards add.) Taking the length of the wall to be 20 ft., the average length of the footings will be 20 ft. plus (2 ft. 3 in. average thickness — 1 ft. 6 in. width of neat work) equals 20 ft. 9 in. The height of the footings, as already shown, including one course of the wall, will be five courses, or 15 in., and the quantity of foot¬ ings equals 20 ft. 9 in. x 1 ft. 3 in. 3 bricks thick equals 25 ft. 11 in. or 26 ft. of work 3 bricks thick. By multiplying 26 ft. by 6 (the number of half bricks in 3 MEASUREMENT OF BRICKWORK 153 bricks) and dividing by 3 (the number of half bricks in 1 y 2 bricks), the work will be brought to the standard measurement, 26 ft. x 6 3 =52 ft. In ascertaining the quantity of digging, to trenches, concrete, and footings, for a rectilineal building, much labor may be saved by taking an average. Let ABCD (Fig. 218) be the plan taken through the 3-brick wall of a building 50 ft. x 30 ft. out to out. If miter lines be drawn from A to E, B to F, C to G, and D to H, and lines midway between the inner and outer lines, but terminating upon the miter lines, be also drawn, the average length of the walls wiil be found to be 2/47 ft. 9 in. and 2/27 ft. 9 in. Then the dig¬ ging for trenches will be 2/47 ft. 9 in., or 151 ft. x 5 ft. 6 in. x 3 ft. 10 in., which equals 3183 ft. 7 in. cube, or 117 cu. yd, 25 cu. ft. Concrete 151 ft. x 5 ft. 6 in. x 1 ft. 10 in. equals 1522 ft. 7 in. cube cr 56 cu. yd. 11 cu. ft. Footings average thickness equals (3 plus 6) •*- 2 154 BRICKLAYERS’ GUIDE equals 4^2 bricks; the height including one course of wall equals 1 ft. 9 in., which equals 151 ft. x 1 ft. 9 in. x (9 half bricks + 3 half bricks or) 3 equals 792 ft. 9 in. or 793 ft. super of reduced work. To this will be added one of the bottom doubled courses, which equals 151 ft. x 3 in. x (12-f- 3 or) 4. This equals 151 ft. of reduced work, and together 793 ft. plus 151 ft. equals 944 ft. or 3 rd. 128 ft. Brickwork is usually measured first as ordinary stock work, length by height, the thickness stated, extra per foot super being allowed for facings; and all openings, arches, etc., deducted. It is usual to measure floor by floor, starting from the footings to the under side of the ground floor joists, and so on. Taking Fig. 218 as a guide, and supposing the quantities of the wall AB 15 ft. in height, faced with red builders and pointed, with a weather joint, and containing the three 6 ft. x 3 ft. 6 in. window openings, are required, the stock work will measure 50 ft. x 15 ft. 3 bricks thick 750 ft. x (6 + 3) or 750 ft. x 2 equals 1500 ft. reduced work. But from this must be de¬ ducted (3/3 ft. 6 in. x 6 ft.) plus (3/4 ft. 3 in. x 6 ft.) 1 y 2 bricks thick equals 139 ft. 6 in. 1500 ft. — 139 ft. 6 in., equals 1362 ft. 6 in. or 5 rd. 2 ft. The extra for facings, including pointing, will be 50 ft. x 15 ft. super, and added to this six reveals 6 ft. x 14 in., and three soffits of arches, say, allowing for rise, 4 ft. 14 in. From this again will be deducted the superficial measurement of the three window open¬ ings; 50 ft. x 15 ft. equals 750 ft.; 6/6 ft. x 1 ft. 2 in. equals 42 ft.; 3/4 ft. x 1 ft. 2 in. equals 6 ft.; together 750 plus 42 ft. plus 6 ft. equals 798 super; deduct 3/6 ft. x 3 ft. 6 in. equals 63 ft. super; leaving 798 ft, — 63 ft or 753 super. MEASUREMENT OF BRICKWORK 155 Chimney Breasts. — Measure the width by the height, stating the thickness of the work; deduct the fireplace opening. The flues are taken in as if solid, pargeting to these being numbered. Ovens and coppers arc also measured as solid, deducting the ash-hole only. Arches.—The face and soffit are measured separately, and afterward added. The camber arch (Fig. 185) will serve as an example for measuring. The opening being 3 ft., but taking 12 in. as depth of face, add one skewback, making it 3 ft. 3 in. x 12 in. (depth of face), 3 ft. x 4^ in. soffit; the superficial measurement in this case will then be 4 ft. 4 x / 2 in. For all radial arches, pass the tape round the face, midway between the intrados and extrados, arrive at the amount, and multiply by the depth of the face; then serve the soffit in a similar manner, multiplying by the depth. Taking Fig. 176 as an example, the face is found to measure 3 ft 9 in. x 12 in. equals 3 ft. 9 in., soffit 3 ft. 2 in. x 4 y 2 in. equals 1 ft. 2 in. and together 4 ft. 11 in. The practical man sometimes finds a difficulty in multiplying by such awkward quantities as 6. ft. 9 in. 4in.; but, by a little thinking, these become quite easy. Feet multiplied by feet will give square feet, e.g., 12 ft. x 12 ft. equals 144 ft. Feet multiplied by inches equal twelfths of feet; e.g., 20 ft. x6 in. equals sq. ft.; inches multiplied by inches equal square inches. Feet multiplied by 6 in. will give half the amount multiplied; thus 12 ft. x 6 in. equals 6 ft. square. Feet multiplied by 3 in. will give one quarter of the amount multiplied; 12 ft. x 3 in. equals 3 ft. square. Feet multiplied by 9 in. will give the last two results BRICKLAYERS’ GUIDE 156 combined; 12 ft. x 9 in. equals ( y 2 of 12) equals 6, plus (}( of 12) equals 3, together 9 ft. square. Feet multiplied by 4^ in. will first be taken as the last and half of that again taken, because 4 y 2 in. is half of 9 in. Feet multiplied by 2^ in. would be half of the above, for the same reason. Feet multiplied by 4 in. will give one-third of the amount multiplied, 4 in. being one-third of 12 in. Feet multiplied by 8 in. will give twice the result of the last, 8 in. being two-thirds of 12 in. To reduce cubic feet of brickwork to superficial feet of standard thickness, deduct one-ninth, e.g., 40 ft. x 20 ft. three bricks thick equals 1600 ft. reduced work; compare with 40 ft. x 20 ft. x 2 ft. 3 in. equals 1800 cu. ft.; take from this one-ninth of 1800 ft. or 200 ft., leav¬ ing 1600 ft. reduced work as before. Practical men usually take pointing by the square of 100 ft. super. To measure gables or pediments, take the central height by half the base for superficial measurement, and for brickwork according to the bricks thick. To find the area of a circular opening, multiply the square of the diameter by 0.7854; e.g., diameter of circle, 10 ft. 10 ft. x 10 ft. equals 100 ft. x 0.7854 equals 78.54. To measure fair cutting to a circle, multiply the diameter by 3.1416; e.g., diameter of circle, 10 ft. 10 ft. x 3.1416 equals 31.416. For a semicircular arch, half the above, e.g., diam¬ eter of semicircular arch, including depth of face on each side, equals 10 ft. Fair cutting round the arch equals 31.416 as above for the whole, -5- 2 equals 15.708. MEASUREMENT OF BRICKWORK 157 In measuring brickwork over 60 ft high from the ground, it should be kept separate, and divided into heights of 20 ft.', viz., 60 to 80, 80 to 100, etc The reason for this is that the higher the work goes the more expensive it becomes to build. Keep the following work separate: Brickwork built overhand. Raising on old walls, stating the height the work commenced from ground level. Circular brickwork. Half-brick partition walls. Sleeper walls. Measure hollow walls as solid. The following work is usually taken at the yard super: Lime-whiting; pointing when not included with the facings; brick-nogging, including timbers, stating if built flat or on edge; cement floated face, stating thickness, if to falls, and if floated or troweled; all kinds of paving; wall tiling, giving full descriptions. Work measured by the foot super: Damp-proof courses; trimmer arches; fender walls; sleeper walls; half-brick partition walls; arches generally, except gauged; facings, keeping the different kinds separate. Work measured at per foot run: Cement filleting, cuttings under 6 in. wide, pointing flashings, cutting chases for pipes, brick on edge, and other kinds of copings. Items numbered: Bed and point frames; setting stoves and ranges, fixing chimney pots, ventilating bricks, parget and core flues, rough relieving arches. Hoop-iron bonding is measured at per yard run, adding 5 per cent to the length for laps, stating it tarred and sanded, and making no deductions for openings. I5» BRICKLAYERS’ GUIDE When finished estimating as above, add at least 7J^ to 10 per cent to the whole amount for extra scaffold¬ ing, and contingencies generally. Some builders add as much as 15 or 20 per cent to estimate, but, when competition is sharp, the contractor adding this large percentage will stand a poor chance of securing the work.* TOOLS USED BY THE BRICKLAYER AND HIS HELPERS The tools shown in the Frontispiece (which see), figuring from 219 to 237 included, are used by the bricklayer and his helper. There are other tools also made use of that are not included in this list, such as the iron or steel square, various forms for shaping bricks, trestles, stands and other appliances for special work; but the ones shown cover the main ground. There is: 1, the pick for breaking up hard ground; 2, the grafting tool for digging out earth such as stiff clay; 3, the shovel; 4, the chalk line; 5, boning rod, for taking levels; 6, spirit level; 7, hod made to carry about 12 bricks, or 2 /i of a bushel of mortar; 8, a larry or hoe for mixing mortar; 9, the beedle or mall, is a large wood mallet with a circular pine head, with rounded ends about 18 in. long and 15 in. in diameter, with a handle about 3 ft. long. It is used by the pavior for punning paving stones into their position when bedding, as shown in Fig. 238; 10, the rammers are of two kinds—1st, that used for ramming granite sets in roadways, which consists of a cylindrical piece of wood *Much of the foregoing matter has been taken from “Brick¬ laying and Brick-cutting,” by H. W. Richards, a most excellent work. TOOLS USED BY BRICKLAYERS 159 about 3 ft. 6 in. long, with a vertical handle at top and a horizontal handle about half-way up, as shown in Fig. 239; 2d, that used for the bottoms of trenches and for consolidating ground. They are of the shape shown in Fig. 240, the head being of iron and about 10 lbs. in weight; the handle is of ash, about 10 ft. long. Bricklaying Tools. — 1, large trowel used for the spreading of mortar and the bedding of bricks; 2, the 2-ft. rule; 3, the plumb-rule and bob for the carrying up of walls perpendicularly; 4, the short straight-edge, about 3 ft. in length, with the brick courses marked on it for the building up of corners; 5, the spirit level for testing the horizontality of work; 6, line and pins for building the portions of walls straight between corners. i6o BRICKLAYERS' GUIDE Erick-cutting Tools. —Rough cutting: I, the large trowel; 2, the club hammer and bolster, for cutting with greater exactitude than with the trowel; 3, the cold chisel for the cutting of chases and for general work. Fair cutting, hard bricks: 1, the tin saw for making an incision }£ of an inch deep, preparatory to cutting with bolster; 2, the chopping block, which is an arrangement of two blocks of wood so fixed as to sup¬ port a brick in an angular position convenient for cut¬ ting; 3, the scutch consists of a stock and a blade, the latter generally formed of a flat file about 10 x 1 in., sharpened at both ends and fixed in the stock by means of a wedge. This displaces, and is an irnprovement on, the old brick axe, as the blade can be removed and sharpened readily; it is used to hack away the rough portions on the side of a brick after the edges have been cut by the tin saw and bolster. Fair cutting, soft bricks: 1, the saw consists of a frame holding the blade, which consists of twisted soft steel or malleable iron wire (No. 16 B.W.G.), and is used for cutting soft rubbing bricks; 2, the rubbing stone is a circular slab of gritty stone 20 in. in diam¬ eter, for rubbing the faces of bricks to a true surface; 3, the mould is a wood box enclosing bricks that are to be cut to a shape, the sides of the box being formed to that shape, and the edge over which the saw blade works is protected by a strip of zinc; 4, the square, bevel, and compasses are used in the setting out of work. Pointing tools consist of: 1, small trowels for filling up joints of new brickwork; 2, the pointing rule, which is a feather-edged straight-edge with two small pieces 3/8 in. thick nailed at each end to keep the rule away BRICKLAYERS’ MORTAR 161 from the wall and allow the trimmings to fall through; 3, the frenchman, for trimming joints, consists usually of an old table knife, with the end ground and turned up, as shown in plate; 4, the jointer, used for tuck pointing in old work. BRICKLAYER’S MORTAR Mortar. —The mortar is composed of one of lime to two or three parts of sand, or from one of Portland cement to one to four of sand. Lime mortar some¬ times has cement added to it to increase its strength and hasten its setting. Lime mortar should not be used when fresh nor in an untempered condition, as in that state its cohesive value is small and it is difficult to work; but after making should be left two days at least, then turned over and beaten up again. This tempering gives it the property of working evenly and fat. Cement mortar should be used as soon after making as possible, as the setting action commences immediately after mixing and any further working up of the mortar lowers its ultimate strength. Building During Frosty Weather. —All brickwork should be suspended during frosty weather, as its sta¬ bility is endangered by the disintegration of the mortar by the frost while it is wet. When the work is urgently required it should be carried up in cement mortar in the intervals between the frost; but all the freshly built portions should be carefully covered and protected on any recurrence of the frost. Technical Terms. —Course is the name given to the row of bricks between two bed joints; the thickness is taken as one brick plus one mortar joint, in this work; BRICKLAYERS’ GUIDE 162 unless otherwise stated, it will be considered as 3 in., or, as technically described, four courses to the foot. It usually requires about 1 yi barrel of lime and 1 yd. of sand to make the mortar for 100 bricks, and one man with 1tender will lay 1,500 to 2,000 bricks per day; that is, four masons and five helpers will lay about 8,000 brick, but this should be reckoned on straight walls. The same proportions of sand and lime, or cement and lime, may be used also for masonry. Allow 12 bushels sand to one barrel. Allow about .0012 bushels fireclay for each 100 brick and 1 barrel of Portland cement to 800 brick. A load of mortar is equal to one cu. yd. It requires 1 cu. yd. of sand and 9 bushels of lime; it will fill 30 hods. A bricklayer’s hod measures 1 ft. 4 in. x 9 in., equals 1,296 cu. in. It holds 20 bricks and weighs about 113 lbs. when full. A single load of sand is equal to I cu. yd.; a double load, 2 cu. yd. A measure of lime is one load. One barrel of fire clay will make a thin mortar for 1,000 bricks. One part cement to two parts sand for cement mortar. Mortar. —One part of lime to 3 or 3^ parts of sharp river sand; or 1 part of lime to 2 of sand and 1 of blacksmith’s ashes. Brown Mortar. —One-third lime, two-tnirds sand, and a small quantity of hair. This is for plastering. Coarse Mortar. —One part of lime to four of coarse gravelly sand. One rod of brickwork requires 1 cu. yd. of lime and 3.^ jingle loads of sand; or, 36 bushels of cement and 36 bushels of sharp sand. . . ... BRICKLAYERS’ MORTAR 163 One yard, or 9 superficial feet, 1% bricks thick, requires 2^ bushels of cement. One superficial yard of pointing brickwork in cement requires yi of a bushel. Some kinds of cement set so fast that it is not safe to mix more than can be used within twenty minutes. Mortar made of cement, worked after it begins to set, becomes worthless. The following are the rules generally used by masons in figuring brickwork: Corners are not measured twice. Openings over two feet square are deducted. Arches are counted from the spring. Pillars are measured on the face only. To find the number of bricks in a wall. 4I in. wall per superficial foot.... 7 bricks. 9 in. wall per superficial foot.... 14 bricks. 13 in. wall per superficial foot. . . .21 bricks. 17 in. wall per superficial foot.. . .28 bricks. 22 in. wall per superficial foot.... 35 bricks. 26 in. wall per superficial foot.. . .42 bricks. 30 in. wall per superficial foot... .49 bricks. And seven bricks additional for every half brick added to the thickness of the wall. One foot superficial of gauged arches requires 10 bricks. One thousand bricks closely stacked occupy about 56 cu. ft. One thousand old bricks, clean and loosely stacked, occupy 72 cu. ft. Stock or place bricks generally measure 8^ x 4^ x 2^ in., and weigh from 5 to 10 pounds each. GENERAL SPECIFICATION CLAUSES MATERIALS BRICKS 1. All bricks intended for use under this Specification must be the best of their respective kinds, hard, square, sound, well- burnt, and even in size. No brick must absorb more than one- sixth of its dry weight in water during one day’s immersion. Samples of each kind, selected at random from the load, must be deposited with and approved by the architect before any of that particular kind are laid. Note. —If the bricks are not specified from particular makers the following may be added to the foregoing clause: And the architect is^ to be informed from what manufacturers the bricks are being obtained, if he so desires. All bricks shall be carefully handed from the carts and stacked, and no broken bricks or bats are to be brought upon the ground. 2. All hard, sound, clean, and approved old bricks, obtained from pulling down the old buildings on site, may be re-used where directed. 3. The stock bricks are to be (obtained from.) or (equal to the manufacture of.) similar in all re¬ spects to the samples deposited with the architect. 4. The stock bricks for facings are to be carefully selected for their evenness ot color and face, and the visible arrises must be undamaged. 5. The pressed (red) facing bricks are to be (obtained from .) or (equal to the manufacture of.) similar in all respects to the samples deposited with the architect. Iii all cases the visible arrises must be undamaged. 6. The hard, wire-cut gault bricks are to be (obtained from . .) or (to be equal to the manufacture of.) similar in all respects to the samples approved by the architect. 164 GENERAL SPECIFICATION CLAUSES 165 7. The cutters or rubbers are to be obtained from. or other approved manufacturer, equal in quality, free from all lumps and flaws, and similar in all respects to those approved by the architect. 8. The salt-glazed facing bricks must be slip-glazed, and are to be obtained from.or other approved manufacturer They must be fairly uniform in tint and equal in all respects to samples approved by the architect. 9. The salt-glazed bricks are to be obtained from. or other approved manufacturer, fairly uniform in tint, and equal in all respects to samples approved by the architect. 10. Reveals, arches, projecting piers, etc., in salt-glazed work are to have bull-nosed angles. Any squints, etc., to be in salt- glazed quoins to required angle. 11. The enamel-glazed bricks are to be obtained from ..or other approved manufacturer. Samples of the required color or colors must be deposited with and approved by the architect before any of this work is executed. Provide enamel-glazed bull-nosed angle bricks for reveals and arches to windows and door, projecting doors, etc. Provide all enamel- glazed quoins to required angles for squints, etc. 12. The firebricks are to be obtained from.or other approved maker (raw and unburnt) or (thoroughly burnt and vitrified), and equal in all respects to the samples approved by the architect. 13. The smoke flue pipes (with air flues combined) are to be of the best fireclay, and of approved stock pattern, to be obtained from.. and equal to the samples approved by the architect. 14. The moulded strings, stops, cornices, angles, sills, jambs, plinths, panels, and keys, etc., shown on details, are to be obtained from the same manufacturer supplying the facing bricks, and of similar make, equal in all respects to the samples approved by the architect. 15. The coping bricks are to be (as per detail drawing) or (of approved stock pattern), from.or other approved maker.inch by.inch, straight, and even col¬ ored, and all arrises and angles must be perfect. 16. The bonding bricks for hollow walls are to be obtained from., of improved bent pattern, equal to samples approved by the architect, and of the following size: Lower i66 BRICKLAYERS’ GUIDE flange,.inch; middle flange,.inch; upper flange, inch. 17. The.bricks for (the 4Einch groined arch work) are to be made by.or other approved maker, each brick cut to the proper size and radius as shown on the detailed drawing, and marked before it leaves the works with a number corresponding to that on the drawing showing its proper position in the arch. SAND, ETC. 18. To be clean, sharp, pit or fresh-water sand; coarse grained, and of approved quality. To be entirely free from loam, clay, dust, or organic matter. If directed it must be washed, when used with cement. 19. If the lime mortar is mixed in a mortar mill, the architect, at his discretion, may allow the contractor to substitute a certain proportion of clean, hard brick, hard burnt ballast, or other approved material in lieu of sand. Such permission shall be given in writing, and shall clearly state the exact proportion of the substitute material which the contractor will be allowed to use. WATER 20. The whole of the water required for the works must be perfectly fresh and clean, and free from any chemical or organic taint. LIME MORTAR 21. The limes for mortar shall be the best of their respective kinds, obtained from (manufacturers approved by the architect) (the firms hereinafter specified), and shall be fresh burnt(and ground) when brought on the works. (Add the following if firms are not specified;) The contractor shall supply the architect, at the latter’s re¬ quest, with the names of the firms from whom the lime has been obtained. (Add the following if firms are specified:) The contractor shall satisfy the architect, if required by him to do so, that the lime is being obtained from the specified firms. (Add the following where ground lime is specified;) The contractor must satisfy the architect, by analysis or other¬ wise, that the lime is not adulterated or air-slaked. GENERAL SPECIFICATION CLAUSES 167 22. The lime shall be thoroughly slaked at the scene of opera¬ tions by the addition of sufficient water. During the process it shall be effectually covered over with sand to keep in the heat and moisture. All lime must be used within ten days of slaking. 23. The contractor shall, at his own expense, provide a proper mortar mill, worked by steam or other approved power for the due incorporation of the materials, and all expenses in connection therewith shall be defrayed by the contractor. 24. If a mortar mill is not provided for the making of the mor¬ tar, the contractor will be required to thoroughly screen the materials before mixing to get rid of any dangerous and refractory lumps. 25. A proper stage is to be provided to receive the lime mortar when made. The mortar in no case to be deposited on the ground. 26. The materials for all lime mortars are to be measured in the proper stated proportions, in quantities sufficient only for each day’s requirements. 27. Fat lime mortar must not under any circumstances be used for the purposes of the specification. 28. The stone lime mortar for brickwork above ground level shall be composed of one part of gray lime (obtained from.) and two (three) parts of sand, mixed with a sufficiency of water and thoroughly incorporated together (in a mortar mill). (The lime and sand shall be mixed together in their dry state before being put into the mortar mill.) 29. The lias lime mortar shall be composed of one part of blue lias lime (obtained from. .....), and one part of sand, mixed with a sufficiency of water and thoroughly incorporated together (in a mortar mill). (The lias lime mortar for brickwork above ground level shall be made in the same manner, but in the proportions of one part of lime to two parts of the sand.) (The lime and sand in their dry state shall be mixed together on a proper stage before being put into the mortar mill.) 30. The blue mortar shall be composed of three parts of fine foundry ashes, two parts of ground stone lime, and two parts of sand CEMENT MORTAR 31. A proper stage is to be provided for mixing Portland and Roman cement mortar upon, and the water must be added from a can with..a fine rose. - 168 BRICKLAYERS’ GUIDE 32. No cement mortar that has become partially set shall be revived or re-used. 33. The Portland cement shall be obtained from. (an approved maker), and shall be of the best quality composed entirely of thoroughly well burnt clinker ground fine enough to pass a sieve of 2,500 meshes to the square inch, without leaving more than 10 per cent behind. The cement shall not contain more than 1 per cent of magnesia and 63 per cent of lime. It shall weigh not less than 112 lb. per striked imperial bushel when lightly filled into the measure from an inclined trough placed 12 in. above the top of the measure. Test briquettes made of the cement, mixed with 18 per cent by weight of water, shall be capable of maintaining—after seven days’ immersion in water—a tensile strain of 350 lb. per square inch, the immersion to commence within twenty-four hours of the briquettes being made. The temperature of the atmosphere and water in which the test briquettes are made shall not be less than 40° Fahr. The tensile strain shall be applied at the rate of about 400 lb. per minute. Samples of the cement when made into a paste with water and filled into a glass bottle or test-tube must not in setting become loose by shrinking from the sides, or crack the vessel. 34. The cement shall be emptied and spread upon the dry wooden floor of a covered shed to a depth not exceeding 2 ft. for a period of not less than 14 days (or such other period as may be considered necessary) and shall be turned over from time to time as may be directed by the architect. 35. The cement shall be delivered on the works in such quan¬ tities as to allow sufficient time for testing before being required for use, and the contractor shall be entirely responsible for any delay or expense caused by the rejection of cement which does not satisfy the special requirements. 36. The Portland cement mortar shall be composed of one part of Portland cement to two parts (one part) of sand, mixed together, turned over, and thoroughly incorporated with a sufficiency of water. It is to be made in small quantities from time to time as required, and must be used within one hour of mixing. 37. The Roman cement is to be of the very best quality, and obtained from an approved manufacturer. The raw stone shall be fine grained, and after being thoroughly burnt, shall be ground to a fine powder The finished cement must not weigh more than GENERAL SPECIFICATION CLAUSES 169 78 lb. per striked bushel, or more than 70 lb. per trade bushel, and must be stored in air-tight drums or casks, and kept in a dry place in free air currents. 38. The Roman cement mortar shall be composed Of owe part of Roman cement and one part of sand, mixed together with a sufficiency of water and thoroughly compounded. Owing to the quick-setting property of the cement, the mortar must be mixed by an experienced workman close to the position at which it is required and used immediately. When once partially set, it must not be revived. 39. The selenitic cement is to be obtained from the patentees, and mixed and used in accordance with the printed instructions issued by them. 40 The fireclay is to be of the best quality, and from the same manufacturer supplying the firebricks. DAMP COURSES 41. The damp course is to be formed with stoneware (fireclay) perforated vitrified blocks . . . .in. by . . . .in., and of the several widths required for the respective walls. The blocks are to have ribbed surfaces and tongue and grooved joints, 42. The bituminous sheet damp course is to be obtained from .and laid (in accordance with their instructions) by them (the contractor given due and reasonable notice, as arranged, when the walls are ready, so that there may be no delay). WORKMANSHIP CLAUSES FOR GENERAL WORK PRELIMINARY 43. All brickwork is to be set out and built of the respective dimensions, thicknesses, and heights shown on the drawings. 44. All bricks are to be well wetted before being laid. The tops of the walls where left off are to ,be well wetted before recom¬ mencing them, as often as the architect may deem necessary. 45. All joints are to be thoroughly flushed up as the work pro¬ ceeds. The vertical joints in the heading courses of English bond are to receive special attention. 46. Carry up walls in a uniform manner, no one portion being raised more than 3 ft above another at one time. All perpends, BRICKLAYERS’ GUIDE 170 quoins, etc., to be kept strictly true and square, and the whole properly bonded together and levelled round at each floor. 47. No brickwork is to be carried on during frosty weather, unless with the written permission of the architect who will give special directions as to the manner in which the work is to be per¬ formed. All brickwork laid during the day shall (in seasons liable to frost) be properly covered up at night with felt, sacking, boards, or other approved non-conducting material. Should any brickwork, laid on the day previous to a frost, become affected or damaged through not being covered or properly protected as pre¬ viously specified, or by reason of the exceptional severity of the weather, the architect, at his discretion, may require the whole or any part of such brickwork to be removed and reinstated by the contractor at his own expense. BOND 48. Brickwork generally except facings (all brickwork) to be laid in English bond consisting of alternate courses of headers and stretchers. Snap headers will not be permitted, and bats only as closers. 49. All facings are to be executed in Flemish bond, consisting in each course of headers and stretchers alternately, to break joint accurately. 50. Cut indents in alternate courses of existing brickwork, and tooth and bond new brickwork to same in cement mortar. 51. Lay in walls, at intervals of four courses, a layer of 1| in. stabbed hoop-iron to each 4J in. of thickness of wall, lapped or hooked at all angles. JOINTS AND POINTING 52 The height of four courses of bricks laid in mortar is not to exceed by more than one inch the height of the same bricks laid dry. 53. The exterior facings are to be pointed with a neat weather joint in cement (blue mortar) cut m top and bottom, a sample of which is to be approved. 54. The interior facings to cellars are to be pointed with a flush joint neatly struck with the point of the trowel. 55. The joints to gauged work are to be pointed with. (time putty) (cement mortar). 56. The enamel and salt-glazed facings to be flush pointed in GENERAL SPECIFICATION CLAUSES lyi Parian cement, tinted to color of the glaze, the white enamel- glazed facings to be flush pointed in Keen’s cement. 57. All internal walls, excepting those otherwise described, to be left rough for plaster. 58. Rake out joints for and point to all flashings in cement and also all frames. FOOTINGS AND PIERS 59. Footings to be formed to spread on each side of the walls, half the respective thickness of same at base, diminishing in reg¬ ular 2J in. offsets to proper thickness of walls. The courses of footings are to be laid of headers where practicable. 60. All underpinning to be executed with approved hard bricks, laid in cement mortar, well grouted at every course, and carefully wedged up with slafe, provided by the contractor. 61. Lay over the full thickness of all walls and piers at the lev¬ els shown on drawings the.horizontal damp course. 62. The outside faces of vault walls, dry areas to have approved asphalt damp course, $ in. thick, laid thereon from the level of horizontal damp course to top of walls, and continued over top of vaults, and turned up around coal or ventilating plates or pave¬ ment lights, as required, to make vaults thoroughly water-tight. 63. All isolated piers carrying weights, and elsewhere if de¬ scribed, to be built in pressed bricks laid in cement and grouted at every fourth course. 64. Build honeycomb (solid) fender walls on proper footings to ground floors where shown. 65. (a) Build up dry area wall as shown on drawings in cement mortar, arched over into main wall three inches below ground level. ( b ) Build up dry area wall as shown on drawings in cement mortar. Bed and point stone cover (provided by “Mason”), as shown, in cement mortar. WALLS GENERALLY 66. Build in, or cut, bed, and pin in, all sills, thresholds, steps, landings, corbels, ends of joists, etc., in cement, and point as re¬ quired. Build in frames, bedded solid in reveals, where specified to be built in. 67. Brickwork to be well pinned and backed up to all stone¬ work and terra-cotta, and cut and fitted to ends of all steel joists, girders, lintels, etc. 172 BRICKLAYERS’ GUIDE 68. Build in brickwork where required, fixing blocks (provided by “concretor”) for fixing carpenters’ or other work. 69. Build half-brick walls, small piers between windows and elsewhere as directed, in cement mortar. 70. Build chases and reveals in walls to receive frames, pipes, light wiring, etc., as shown on drawings, or required. 71. Bed all plates, lintels, templates, cover stones, etc., in cement as required. 72. Neatly cut and fit all facings to stone or terra-cotta dress¬ ings, arches, etc., and execute all rough and fair cutting as required. 73. Leave horizontal chases in walls to receive concrete floors or build sailing courses as shown to support same. 74. Turn rough segmental relieving arches in cement over all lintels where practicable. 75. Oversail where possible to support concrete floors and pro¬ jections and to receive plates. 76. Level up on top of all riveted girders with plain tiles and cement. 77. Build in.air bricks (provided by “terra¬ cotta and Faience worker”) (“founder”), where shown on draw¬ ings, and form cranked air-ducts to them in the wall, rendered in cement and sand. 78. The panels intended for carving are to be executed in rubber brick, as shown on drawings, set in shellac. 79. All niches, panels, and other enrichments to be executed in .as shown on drawings. FIREPLACES, CHIMNEYS, ETC. 80. Build in over each fireplace opening a wrought iron bar, provided by “smith,” turn rough brick segmental arch over same in two rings, and properly contract the opening, and form throats to flues as detailed. 81. Build all smoke and ventilation flues of full bore shown, graduate all bends and parget flues as the work proceeds, and carefully core same, leaving openings in face of chimney-breasts where required for coring, and afterwards pin up same and make good. 82. Line all flues shown circular on plan with.in. un¬ glazed terra-cotta flue pipes, and provide all requisite bends, pur¬ pose made or otherwise. 83. Properly bond the withes and other brickwork of all flues. GENERAL SPECIFICATION CLAUSES 173 84. Build all chimney stacks above roof line in cement mortar with selected pots set in same, and well flaunched up and weath¬ ered in cement, to detailed drawing, joints left open for pointing other brickwork. 85. Rough render all chimney-backs, and also brickwork to flues where near woodwork, in cement. 86. Carefully set all stoves, provided by “founder,” with brick in mortar backing, fix iron and wood mantels securely with iron cramps pinned in cement; set kitchener in accordance with in¬ structions with firebrick flues, and provide all firelumps, fireclay, etc., required. 87. Carefully set, where shown on drawings, all flue plates and soot doors and frames, provided by “founder.” 88. Set in brickwork, as described, with firebrick linings in fire¬ clay to flues, furnace pan, including all ironwork, dampers, soot doors, etc., provided by “founder”; the top and front to be ren¬ dered with Portland cement and sand, in equal proportions, f in. thick. 89. Turn half-brick trimmer arches in cement 18 in. wide and 12 in. longer at each end than the width of the openings to all fireplaces where there is no support underneath. 90. Bed and point hearthstones in cement mortar. FACINGS 91. Pace the whole of the.excepting where otherwise specified, with best selected stock bricks, uniform in color. 92. All arches occurring in stock brick facings to be segmental arches in second quality malms, axed and set in cement. 93. Face the elevations tinted.on drawings with .’s first quality.facing bricks, carefully executed in accordance with details of elevations. Build all moulded strings, cornices, angles, etc., in similar red bricks, with moulded stops as shown on details. 94. Turn over all basement openings in.elevations, plain segmental arches in.rings in cement. Turn over all other openings where shown in brick on.elevations, gauged arches in red rubbers, accurately and closely jointed. That elliptic arches over.floor openings on.eleva¬ tions to have voussoirs of similar gauged rubbers, alternating with terra-cotta voussoirs, provided by “terra-cotta and Faience worker,” and moulded to details. 174 BRICKLAYERS’ GUIDE 95. Face the following portions of back elevations: the light area to.and also the walls of lavatories in vaults, with.quality.bricks in fine mortar. 96. Reveals and arches to windows and doorways occurring in glazed work are to have bull-nosed angles, also all projecting piers in lavatories to have ditto. Any squints, etc., to be in white glazed quoins to required angle. 97. Turn segmental arches in glazed half brick rings in cement over openings as shown on elevations. SUNDRIES 98. Build 4J in. (glazed brick) piers (in scullery), where shown on drawings, to support stoneware (stone) sink, and properly bed and point same in cement mortar. 99. Cope parapets where shown to have brick coping, with two courses of plain tiles bedded in cement to project in. from faces of wall, or.. . patent drip tiles, and brick on edge coping the thickness of wall bedded and pointed in cement mortar and ramped as required. 100. Cope parapets and other walls where shown with purpose made coping bricks the thickness of the wall, pattern No. .’s list, bedded and pointed in cement mortar.. 101. Bed and point stone copings, provided by "mason,” in cement mortar with the joints joggled. 102. Cut and pin in ventilating flues where shown approved ventilators, provided by “ventilating engineer.” 103. The contractor shall, before pointing, clean down all brick facings, and make good all putlog and other holes throughout the work as it proceeds, and point the same. 104. Cut away, etc., as required for other trades, and make good after same. For Limewhiting, see “Painter’s Specifications.” HOLLOW WALLS 105. Build up the hollow walls as shown on drawings in two thicknesses, the outer thickness to be 4£ in., the inner.in., with a 2|-in. cavity between, the thickness of the entire wall being .in. Bond the two thicknesses together with. wall ties placed at a distance apart of 3 ft. horizontally an^ 12 in. vertically. The cavity is to be kept clear of all rubbish or GENERAL SPECIFICATION CLAUSES 1/5 mortar droppings by movable boards or other means. Leave openings at the base and clean out the cavity at completion, the openings afterwards to be bricked up uniform with surrounding work. The wall ties to be carefully laid and in no case to fall towards the inner thickness of the wall. Build into inner face of exterior thickness overall frames a piece of sheet lead, provided by “plumber,” projecting 2 in. beyond each side of lintel and turned up 1 £ in. DAMP-PROOF WALLING 106. Build up the walls in two thicknesses, the outer thickness being 4£ in., the inn^r thickness.in., with a cavity between, the total thickness of the wall being.in. The bricklayer is to leave the cavity face joints free of mortar for a depth of \ in., the cavity being kept clear of mortar droppings with a movable plain board. At a height of every four courses fill up the cavity with.building composition, pre¬ pared and used according to instructions. RETAINING WALLS 107. The retaining wall to be carried up according to the detail drawing, to be built of.bricks laid in cement mortar grouted at every fourth course, to have the exterior face battered, the inner face finished with (diminishing offsets; all as shown. 108. Build in where shown 3 in. land drain pipes to run through the entire thickness of the wall, cut bricks to fit, and make good around same in cement mortar. FACTORY CHIMNEY SHAFT For specification of Iron Cap, see “Founder.” For Lightning Conductor, see “Electrician.” For Painting Iron Cap, see “Painter and Decorator’s Specifications.” 109. The whole of the brickwork throughout, including foot¬ ings, walls, arches, string courses, cornices, etc., is to be built and carried up in accordance with the drawings, and is to be of the various thicknesses, heights, etc., or other dimensions as shown thereon, finishing at the top length of.ft., which is to be.ft -- in. in thickness and is to be set in cement mortar. 176 BRICKLAYERS’ GUIDE 110. All brickwork, except where otherwise specified, is to be built in lime mortar and in old English bond. All the walls are to be carried up uniformly all round, aad no part is to be left more than 3 ft. lower than any other. Each course is to be carried up to a uniform level throughout, and the whole of the work is to be built true, and the perpends strictly kept. 111. Two arched openings are to be formed (. ..ft. by .ft.) in the base of the shaft, as shown, for the connection of the main flues thereto. The semicircular arches over open¬ ings to be turned in three 4^ rings of brickwork carefully bonded in mortar and lined with firebrick. 112. Form sunk panels in each side of the square pedestal base of the dimensions, and after the manner shown upon the drawings. 113. The brickwork is to be built with neat close joints not exceeding | in. in thickness, and no four courses of bricks to rise more than 1 in. in addition to the height of the bricks laid dry. The cross joints are to be put in solid throughout the whole vddth of the bricks and the wall joints flushed up solid, and grouted with every course. The bricks for facing must be properly bonded in at each course with the brickwork as the work proceeds. 114. The contractor shall do all cutting required for forming openings, splays, miters, chases, circular work, indents, recesses and skewbacks, and shall make good all putlog and other holes throughout the work as it proceeds, and point the same. 115. The w r hole of the exterior brick facing is to be pointed with a neat flat joint, and is to be jointed. The interior faces of walls are to be jointed with a neat flat and flush joint. 116. The.ft. by.4t. main flue entrance in the base of the shaft which is not required for immediate use >s to be built up as shown on plan, with 14-in. brickwork, consisting externally of 9-in. ordinary bricks and 4J in. internal facing of firebrick properly bonded thereto. 117. Build in a 3-in. cast-iron pipe (water main strength), with a screw hexagonal cap and spanner through the brickwork in the position shown upon the plan, for the purpose of inserting testing apparatus, etc. 118 The.brick cornices to be constructed in the top¬ most.ft length of the shaft, are to be of depths and projections shown upon the plans. They are to be thoroughly GENERAL SPECIFICATION CLAUSES 177 well bonded together and set in cement, and if considered neces¬ sary by the architect are to be further secured with metal cramps run in with lead. 119. In the topmost length of the shaft, and between the two projecting blue brick cornices above mentioned, five projecting ribs are to be formed of facing bricks on each side of the octagon, as shown on the drawings. These ribs are to be spaced 4 \ in. apart in the clear, are to be 4J in. in width on the face, to project 3 in. from the face of the shaft, and are to extend.ft. in length. They are to be properly corbelled out at the bottom, and finished at the top with splayed blue bricks. All to be set in Portland cement mortar. 120. The shaft is to be internally lined with firebrick from the level of the floor of the main flue at its entrance at the base of the shaft to a height of.ft. above floor of main flue. The firebrick lining is to be built circular, is to be in. in thickness and is to have an internal diameter of.ft. throughout its height. An air space of 2 \ in. in width is to be maintained at the back of the firebrick lining, between it and the ordinary brick¬ work. At the upper extremity of the firebrick lining this air space is to be completely oversailed with firebricks bonded into the brickwork, and projecting as shown on the plan. The contractor must be very careful to keep the air space perfectly clear of mor¬ tar or rubbish of any kind. To permit of an air current between the lining and the brickwork, a sliding grid ventilator is to be built in each face of the base of the shaft, near the ground level and a corresponding grid without slides is to be built in each case of the shaft just under the out-sailing course at the top of the lining. All firebrick linings are to be built of the best .purpose-made radius firebricks, well wetted before use, solidly and truly set with the closest possible joints, in pure fireclay cement. The firebrick lining is to be bonded or stayed at intervals as may be necessary for securing same by firebrick bonders into the ordinary brickwork. BRICKWORK DURING FROST 122. The bricks to be used for brickwork during frost shall be kept under cover free from moisture or frost. They are to be taken out only in small quantities as required for use, and are not to be wetted previous to being laid. 123. The water, sand and lime for the mortar must similarly 178 BRICKLAYERS’ GUIDE be kept under cover, free from frost. The lime is to be ground unslaked lime, mixed with the sand in the proportion of one part of lime to two parts of sand. Where the temperature is under 26° Fahr. the proportions shall be one part of lime to one part of sand. The mortar shall be mixed in ashes having a temperature of not less than 34° Fahr. in small quantities as required and used imme¬ diately. 124. The brickwork is to be executed as rapidly as possible consistent with good workmanship, and the courses shall be imme¬ diately covered with sacking as the work proceeds. 125. If the temperature shows the presence of more than 12° of frost, i. e., a temperature less than 20° Fahr., the work shall be immediately stopped. Note. —The following are for brickwork for other trades. FOR “dRAINLAYER” (HOUSE DRAINAGE) 126. Construct the manholes to the sizes and depths shown on the drawings, all depths being calculated from the inverts of the main channels in the manholes. The manholes are not to be built until the pipes entering them, have been properly laid and jointed. 127. The walls to be built of the full dimensions shown on the drawings in selected hard stocks laid in cement mortar in English bond. (The interior face joints for a distance of.ft. above the benches are to be left rough as a key for the rendering.) All (other) joints to be thoroughly flushed up with cement mortar, and are to be neatly struck with the point of the trowel. Point in cement the (exposed) brickwork to interior faces of manholes. Note. —Some architects prefer to have manholes in stock bricks rendered on the interior faces in cement and sand. If ren¬ dering is not desired leave out the words in brackets. 128. The walls to be built of the full thicknesses shown on the drawing, of good hard stocks, with interior facings of (enamel glazed) (salt glazed) bricks in cement mortar in English bond, the joints to be well flushed up, grouted at every fourth course, the brickwork to interior faces being pointed in pure cement and neatly struck with the point of the trowel. 129. To be built as other manholes, but in addition to have a small brick chamber constructed at the side. 14 in by 14 in. by 27 in. in the clear, as shown on drawings An aperture to be formed in the division walls, and to have a.mica valve GENERAL SPECIFICATION CLAUSES 179 built in as shown on drawings as near the top of the manhole as practicable. 130. A chamber is to be formed at one end of.man¬ holes by turning an arch in two 4£- in. rings from side to side as shown on drawings. The height of such chamber from the invert of the main channel to be 6 ft. 131. A chamber is to be formed at one end of the.man¬ hole by partially roofing over with a good stone cover or landing as shown on drawings. The height of such chamber from the invert of the main channel to the underside of the stone to be not less than 6 ft. or more than 6 ft. 2 in. as the courses of brickwork allow. 132. Build up the walls to the heights, lengths, and thicknesses shown on detail drawing (1 stock 2. blue) bricks laid in cement mortar (1. the interior face joints left rough for rendering) (2. grouted in at every course and the joints being neatly struck with the point of the trowel). Form an aperature in division wall 9 in. by 12 in. as shown. Build in stone cover to aperture, stone templates under R. S. joists, hooks for grating chains, etc., as shown on detail. Secure grating channel to walls of filter chamber with holdfasts driven 6 in. into the brickwork. (1. The whole of the interior faces of tank and filter to be rendered and smoothly troweled in cement and sand f-in. thick.) 133. Build in the ends of all pipes at the heights and levels shown on the drawings, or as directed by the architect during the construction of the manholes, rain water tank, and filter etc. Build in step-irons at a height of every four courses of brickwork where shown on plan. 134. All drainpipes passing through manhole, R. W. tanks, filter, or other walls or foundations are to have arched openings formed for them so that they can be withdrawn without cutting and to prevent fractures from settlements. 135. The entrances to manholes, R. W. tanks, filter, etc., are to be corbeled over to the necessary openings for covers, as shown on drawings. 136. The walls to be 9 in. in thickness, built of stock bricks, laid in cement mortar or English bond. The interior face joints of brickwork to be left rough for rendering. The walls to be carried up perpendicularly for flat stone cover. 137. Bed and point all stone covers and landings to manholes in cement mortar bed and point stone covers to.cleaning and i8o BRICKLAYERS’ GUIDE inspection eyes, inspection chambers and all movable covers in lias lime mortar. 138. Bed and point all iron cover frames to manholes, It. W. tanks, inspection chambers, lamp holes, etc., where shown on drawings, in cement mortar. DRAINAGE 139. At the points shown build inspection chambers (or catch- pits).ft. by.ft. internal diameter, in solid 9-in. stock brick, in cement mortar according to detail, the inlet and outlet pipes being built in as directed. 140. Build up face wall at outfall in good hard stocks, 9 in. in thickness, laid in cement mortar. Build in over the drain mouth close iron grating provided by "smith.” The last pipe to be built in to slope slightly downwards and a little projecting in order that the effluent may discharge clear of the face of the wall, all according to detail. FOR “MECHANICAL ENGINEER” 141. Build the engine bed in stock brickwork, and bed on stone cover supplied by “mason.” 142. Build for and set the boilers.according to detail drawing in stock and firebrick. 143. The boiler to be set on fireclay seating blocks, 12 in. long, separated from boiler by wrought iron strips. 144. Line the flues with 4%-in. firebrick and finish against side of boiler with 9 in. by 9 in. quadrant fireblocks. 145. The seating at front end of boiler to be faced out with white enamel glazed brick in fine mortar, and neatly cut to same. 146. Line the blow-off pit with white glazed brick as above, with firebrick bottom. Build in iron drain pipe and bed stone cover supplied by “mason.” 147. Form main flue under boilers.ft. wide, carry through wall.ft. by.ft. The arched flue to chim¬ ney to be.ft. wide and.to crown in 9. in. stock brickwork with 4Lin. firebrick lining. 148. Build manhole to ditto.ft. by.ft. in 9-in. brickwork. Wall up the opening to flue with straight jointed bricks, so as to be removed when required and form sump in ditto. 149. Cover in boiler side and flues with stone flags supplied by “mason.” STONEMASONS’ GUIDE PART II MASONS’ WORK INTRODUCTION A mason, properly speaking, means a builder, which is evident from -the connection between the French words magon, a mason; maison, a house, and maison- ner, to build houses; but in America it is customary to look upon a mason and a stone mason as one and the same, a builder in bricks being always called a brick¬ layer. In Ireland the term masonry is specially applied to stone-walling, as distinguished from the cut stonework used in dressings and other work of a superior description. In this country masonry is the art of building in stone in a similar manner to that of brick, with the exception that brickwork is carried out with uniform sized blocks, thus admitting of a number of definite systems of laying the bricks; whereas in stone, owing to the expense in working the material, the face stones only are squared, and the interior or hearting is filled up with smaller stones roughly fitted with a hammer. The stones are in the great majority of cases of vary¬ ing dimensions, thereby making it a matter of great skill to obtain a proper bond in the work; and owing to the irregular shape of the material the walls have to be made considerably thicker than walls of the same height in brick, with the exception where the walls are built of coursed stones properly squared, in which 181 182 STONEMASONS’ GUIDE case the thickness may be even less than that of brick walls. The great dimensions in which stone may be obtained, lends itself to a much greater degree than bricks for buildings of architectural pretensions, ren¬ dering it possible to have cornices and corbelled work of great projection, which is impossible in brickwork. TECHNICAL TERMS The following is a list, and also an explanation, of some terms used in stonework: Bond, Lap, and Course. —These terms have the same meaning as given under brickwork. Through Stones. —Stones which extend through the entire thickness of walls to tie or bond them. These are objectionable, as damp is more likely to show on the interior of walls where the continuity of the mate¬ rial is uninterrupted. Headers. —The name applied to stones, the lengths of which are Yz to thickness of the wall, laid trans¬ versely. Bonders. —These may be either “throughs” or “headers.” Grout. —This is a thin mortar, which is poured over the stones when brought up to a level surface, to fill up any interstices between the stones in the hearting of walls or other positions as necessity requires. Spalls or Shivers. —These are broken chips of stone, worked off in the dressing. Weathering.— The top face of a stone worked to a plane surface inclined to the horizontal for the pur¬ pose of throwing off the water is said to be weathered, as in sills, cornices, etc. TECHNICAL TERMS 183 Footings. —The object of footings is the same as in brick walls. Stone footings should be large, rectan¬ gular, through stone blocks. Square stones in plan are not so good as oblong. All stones in the same course must be of the same height, but all courses need not necessarily be of the same depth. The breadth of set-offs need not exceed 3 or 4 in. If the expense of stone is an objection, footings may be made of bricks or beds of concrete of suffi¬ cient depth. See chapters on Foundation and on Brickwork. Bed Surface. —The bed surface must be worked in one plane surface. Masons, to form thin joints, often make the beds hollow. This is bad, as it is liable to spall; all the pressure will be thrown on the outer part, which is liable to spall the edge of the stone. Galleting. —The term given when small pebbles are pressed into the face joints of rubble walls to preserve the mortar and to give a pleasing effect. Dressings. —Stones are said to be dressed when their faces are brought to a fair surface; but cut or prepared stones used as finishings to quoins, window and door openings, are described as dressings. Quoins. —In rubble and inferior stone walls, quoins are built of good blocks of ashlar stone to give strength to the wall. These are sometimes worked to give a pleasing effect, and where hammer dressed and chamfered are said to be rusticated. They are, at times, merely built with a rough or quarry face, only having the four face edges of each stone lying in one plane. Window and Door Jambs. —For purposes of strength these should be of cut stone, attention being given that each course is securely bonded. For that reason STONEMASONS’ GUIDE 184 it would not be advisable to build them of rubble. Stoncheons. —The stones forming the inside angle of the jamb of a door or window opening. These are often cast in concrete to effect a saving in labor. Sills. —These are the lower horizontal members of openings; those in stone are usually of one length, being pinned in cement to both sides of the opening. They should be fixed after the carcass of a building has been finished, and any settlement that was likely to occur through a number of wet mortar joints has taken place. They may be plain and square, as for door sills, or sunk, weathered, moulded with drip and with properly formed stools, and grooved for metal water bar, or moulded, grooved and weathered. Corbel. —A stone projecting from a wall to support a projecting feature. Skew Corbel. —Is a projecting stone at the lowest part of the triangular portion of the gable end of a wall supporting the starting piece of coping, and resisting the sliding tendency of the latter. The skew corbels are often tied into the wall by long iron cramps. Kneeler or Skewput. —This is a long stone, tailing well into the gable wall, and resists the sliding tend¬ ency of the coping. Saddle or Apex Stone. —The highest stone of a gable end, cut to form the termination of two adjacent inclined surfaces. Lacing Course. —Owing to the absence of bond in some walls, courses of bricks, three deep, are inserted at intervals, to give strength to the wall and bring it to a level surface. Sometimes the name is applied to a horizontal band of stone placed in rubble or rough walls to form a longitudinal tie. TECHNICAL TERMS 185 String Courses. —Horizontal bands of stone sometimes moulded and projecting, often carried below windows to accentuate the horizontal divisions of a building. Plinth. —A horizontal projecting course or courses built at the base of a wall. These are to protect the wall, and are often built in hard hammer-dressed stones. Cornices. —The moulded course of masonry crowning buildings, generally having a large projection to throw off the rain. Saddled or Water Joint. —To protect the joints of cornices and other exposed horizontal surfaces of masonry, the sinking is sometimes stopped before the joint and weathered off. Any water passing down the weathered surface is guided away from the joint. The expense of this joint often prohibits its use. Blocking Course. —A course of stones erected to make a termination to the cornice, the object being to gain extra weight to tail down the cornice, and to form a parapet. Coping. —The highest and covering course of masonry, forming a waterproof top, to preserve the interior of wall from wet, which in frosty weather might burst the wall. Fig. 52, B. shows a coping flat on the top sur¬ face, which should be used only for inclined surfaces, as on a gable, or in sheltered positions. Saddle-back is the name applied when the upper surface is weath¬ ered both ways; and segmental, when the section of copings shows the upper surface to be a part of a circle. Rebated Joints. —These joints are used for stone roofs and copings to obtain weather-tight joints. There are two kinds: 1, when both stones are rebated; 2, when the upper stone only is rebated. In the first case the stones are of the same thickness throughout, STONEMASONS’ GUIDE 186 their upper surface being level when the joint is made. In the second case the stones are thicker at the bottom edges than at the top, the bottom edge having a rebate taken out equal to the thickness of the upper edge of the stone below it, over which it fits. The part that laps over should not be less than ^ in. thick. The upper surfaces or beds of the stones should be level. Throatings. —Grooves on the under surfaces of cop¬ ings, sills, string courses, etc., acting as drips for any water that would otherwise trickle down and disfigure the walls. Templates. —Slabs of stone placed under the end of a beam or girder to distribute the weight over a greater area. Gable Details. —The tops of stone walls are protected by coping, and these, where placed on steep gables, need support at their lower ends and at intervals; this may be done by constructing a shoulder at the foot, or by the use of skew corbels. The intermediate sup¬ ports are obtained by kneelers, which consist of stones having a part worked as a coping, the remainder tail¬ ing well into the wall. Corbie Step Gables.- —A common method of finishing gables is by constructing a number of steps formed of some hard stone squared, the top surfaces being slightly weathered and known as corbie or crow-step gabling. Gablets. —Many skew corbels are constructed with a small gablet, which gives extra weight to the skew corbel, thus rendering it more efficient for resisting the outward thrust of the coping stones. The apex stones are often treated in a similar manner. Corbel-table. —A system of corbeling supporting a parapet, often forming an architectural feature. TECHNICAL TERMS 187 Einial. —The aspiring ornament of an apex stone often richly foliated. Parapet. —The fence wall in front of the gutter at the eaves of a roof. The castellated parapet is formed by a number of embrasures similar to the parapets used in ancient military buildings, much used in the later Gothic work as an ornamental feature. Diaper Work. —Is the name given to bands, surfaces and panels in the stone work formed by square stones and similar squares, filled in with brick or flint work, giving a checkered appearance. The term is also applied to any ornament arranged in squares upon the surface of ashlar masonry. Tympanum. —The masonry filling in between the relieving arch and the head of a door or window. Advantage is often taken of this to form a ground for carved ornament. Gargoyle. —Is a stone water-spout, employed in build¬ ings of Gothic character to carry off the rain from the gutters. These project sufficiently far to throw the water clear of the building. At present down pipes are employed, but the gargoyle is often retained as an overflow in lieu of a warning pipe. Tailing Irons. —These are formed of H, L, or T irons for holding down the ends of corbels in oriel windows. Lintels. —Wide spans requiring to be bridged by stone lintels (as is the case in the trabeated styles of architecture) are often of a greater dimension than can be conveniently obtained in one stone, in which case the lintel is built up in one of two ways: (1) By an arched construction. The sloping joints in this method are considered objectionable by some, altering as it does the principle of the construction from the beam to the arch, the number of small pieces STONEMASONS’ GUIDE 188 detracting from the general effect. Vertical joints are preferred to inclined. The arched principle, with vertical jointed voussoirs, may be carried out by form¬ ing the joint vertically on and about 4 in. below the face and the remainder to the back, or, if seen on both sides, in the center of the lintel. The stone cut thus form voussoirs of an inch. (2) The method now most usually adopted is to build the lintel up of a number of pieces with vertical joints and in two thicknesses, the front and back portion being made to envelop the flanges of a steel girder, which bridges the whole span and takes its bearing on the columns. The back and front pieces are connected on the soffit, and the upper surface by small copper cramps, the latter being bedded in cement mixed with dust from the stones to be united. The hole soffit is finally rubbed over with a piece of stone similar to the lintels, to render the joint as nearly as possible invis¬ ible. Care must be taken to protect the iron girder from the danger of oxidation by applying one of the preservative processes employed for iron and steel. The stone entablatures built over shop fronts are formed in this way, but have the stone on one side only of the girder, being connected to the same with cramps. The masonry above stone lintels should be disposed to throw, as much as possible, the weight of the super¬ imposed walling on to the supports, and not unneces¬ sarily stress the lintel. Labors.—The following are the chief labors adopted in preparing stone work: Half-Sawing. —The surface left by the saw; half the cost of the sawing being charged to each part of the separated stone. TECHNICAL TERMS 189 Self-faced. —The term applied to the quarry face, or the surface formed when the stone is detached from the mass in the quarry; also the surfaces formed when a stone is split in two. Scabbling or Scappling. —That is, taking off the irregular angles of stone; is usually done at the quarry, and is then said to be quarry pitched, hammer faced or hammer blocked; when used with such faces the stone is called rock or rustic work. Hammer Dressing. —Roughest description of work after scabbling. Chisel Drafted Margin. —To insure good fitting joints in hammer faced stones, a true surface about an inch wide is cut with a chisel, forming a margin on the face of stone. Plain Work. —This is divided, for purposes of valua¬ tion, into half plain and plain work. The former term is used when the surface of the stone has been brought to an approximately true surface, either by the saw or with the chisel. Plain work is the term adopted for surfaces that have been taken accurately out of wind- ingwith the chisel. Half plain is usually placed upon the bed and side joints of stones in ashlar work and plain work on the face. Rubbed Work. —This labor consists in rubbing the surfaces of stones until perfectly regular, and as smooth as possible. The work is accomplished by rubbing a piece of stone with a second piece. During the first stages of the process, water and sand are added, gradually reducing the quantity of sand up to the finish. Large quantities of stones are rubbed by means of large revolving iron discs, on which the stones are placed, and kept from revolving with the disc by means of stationary timbers fixed a few inches STONEMASONS’ GUIDE I 190 above and across the table. Water and sand are added to accelerate the process. Only plane surfaces can be rubbed in this way. Polishing. —Marbles, after the rubbed operation, are brought to a still smoother surface by being well rubbed with flannel and a paste of beeswax and tur¬ pentine or putty. The polishing of granite has been described elsewhere. Boasted or Droved Work. —This consists in making a number of parallel chisel marks across the surface of the stone by means of a chisel termed a boaster, which has an edge about 2 yi in. in width. In this labor, the chisel marks are not kept in continuous rows across the whole width of the stone. Tooled Work. —This labor is a superior form of the above, care being taken to keep the chisel marks in continuous lines across the width of the stone. The object of this and the preceding is to increase the effect of large plane surfaces by adding a number of shadows and high lights. This labor is sometimes known as scabbled work. Axed Work. —Axed work and tooled work are similar labors. The axe is employed for hard stones, such as granite, but the mallet and chisel for soft stones, being more expeditious. The method of preparing the hard stones after being detached from their beds in the quarry is as follows: The stones are roughly squared with the spall hammer; the beds are then prepared by sinking a chisel draught about the four edges of the bed under operation, the opposite draughts being out of winding, and the four draughts in the same plane surface; the portions pro¬ jecting beyond the draught are then taken off with the pick. After the pick the surface is wrought with the TECHNICAL TERMS igi axe, the latter being worked vertically downward upon the surface, and taken from one side of the stone to the other, and making a number of parallel incisions or bats; the axe is worked in successive rows across the stone, the incisions made being kept continuous across the surface. In axed work there are about four incisions to the inch. This labor is used for the beds of stones for thresholds and curbstones, and in this state the pick marks are easily discernible. Fine axed work is a finer description of axed work, and is accomplished with a much lighter axe having a finer edge. In fine axed work there would be eight incisions to the inch. Furrowed Work. —This labor, used to accentuate quoins, consists in sinking a draught about the four sides of the face of a stone, leaving the central portion projecting about of an inch, in which a number of vertical grooves about in. wide are sunk. Combed or Dragged Work. —This is a labor employed to work off all irregularities on the surfaces of soft stones. The drag or comb is the implement used. It consists of a piece of steel with a number of teeth like those of a saw. This is drawn over the surface of the stone in all directions, making it approximately smooth. Vermiculated Work. —This labor is placed chiefly on quoin stones to give effect. The process is as follows: A margin of about % in. is marked about the edge of the stone, and in the surface enclosed by the margin a number of irregularly shaped sinkings are made. The latter have a margin of a constant width of about yi in.between them. The sinkings are made about J^in. in depth. The sunk surface is punched with a pointed tool to give it a rough pockmarked appearance. Pointed Work. —The bed and side joint of stones are 192 STONEMASONS’ GUIDE often worked up to an approximately true surface by means of a pointed tool or punch. This labor is often employed to give a bold appearance to quoin and plinth stones, and where so used it usually has a chisel- draughted margin about the perimeter. Moulded Work. —Mouldings of various profiles arc worked upon stones for ornamental effect. Mouldings are worked by hand as well as by machine. In the former case, the profile of the moulding is marked on the two ends of the stone to be treated by means of a point drawn about the edge of a zinc mould, cut to the shape of the profile. A draught is then sunk in the two ends to the shape of the required profile. The superfluous stuff is then cut away with the chisel, the surface between the two draughts being tested for accuracy by means of straight-edges. The machines for moulded work somewhat resemble the planing machines for metal work. The stone is fixed to a moving table. The latter has imparted to it a reciprocating rectilinear motion, pressing against a fixed cutter of the shape of required profile, or some member of it. The cutter is moved near to the stone after each journey, thus gradually removing the superfluous stuff till the profile is completed. Moulded work is, strictly speaking, the name given to profiles formed with a change of curva¬ ture, and therefore should not be applied to cylin¬ drical sections, such as columns. The weathering properties of stones moulded by hand labor are considered by some far superior to those worked by machinery, as in the latter method the moulding irons, being driven continuously, become heated and partially calcine the surfaces of the stones, thus rendering it peculiarly susceptible to atmospheric deterioration. TECHNICAL TERMS 193 Moulded Work Circular. —This term is given to mouldings stuck upon circular or curved surfaces in plan or elevation. Sunk Work. —This term is applied to the labor of making any surface below that originally formed, such as chamfers, wide grooves, the sloping surfaces of sills, etc. If the surface is rough, it is known as half- sunk; if smooth, sunk, and any other labor applied must be added, such as sunk, rubbed, etc. Circular Work. —Labor put upon the surface of any convex prismatic body, such as the parallel shaft of a column or large moulding, is termed circular work. Circular Sunk Work. —Labor put upon the surface of any concave prismatic body, such as a large hollow moulding, or the soffit of an arch, is termed circular sunk work. Circular Circular Work. —The labor placed upon columns with entases, spherical or domical work. Circular Circular Sunk. —The labor worked upon the interior concave surfaces of domes, etc. Internal Miters. —The name given to the intersections of two mouldings making an angle less than 180 degrees. External Miters. —The name given to the intersection of two mouldings making an angle greater than 180 degrees. Returned Mitered and Stopped. —The name given to a moulding returned in itself, and stopping against an intersecting surface. Long and Short Work. —This work is often used for quoins and dressings in rubble walls, and is especially noticeable in old Saxon work. It consists in placing alternately a flat slab, which serves as a bonder, and a long stone approximately small and square in section. 194 STONEMASONS’ GUIDE This arrangement in modern work is sometimes known as block and start work. Stone Walling. —Is divided - under the following headings: I, Rubble; 2, Block in Course; 3, Ashlar. Illustrations of these various kinds of walling will be shown later on. Rubble walls are those built of thinly bedded stone, generally under 9 in. in depth, of irregular shapes as in random rubble or squared as in coursed rubble. Block in course is composed of squared stones usually larger than coursed rubble, and under 12 in. in depth. Ashlar is the name given to stones, from 12 to 18 in. deep, dressed with ascabbling hammer, or sawed to blocks of given dimensions and carefully worked to obtain fine joints. The length of a soft stone for resisting pressure should not exceed three times its depth; the breadth from one-and-a-half to twice its depth; the length in harder stones four to five times its depth, and breadth three times its depth. Random Rubble. —The name given to walling built of stones that are not squared, but roughly fitted with a waller’s hammer. Random Rubble Set Dry. —In the stone districts boundary walls are built of rubble set without mortar. The top is built of heavy stones, which are usually bedded in earth, to prevent slight movement. TJncoursed Random Rubble Set in Mortar. —In these the stones are used as they come from the quarry, care being taken to obtain them as uniform as possible, and roughly fitting with the waller’s hammer; one bond stone is used in every super yard on face; any open¬ ings between stones to be pinned in with spalls. If TECHNICAL TERMS l 9S good mortar is used, walls built of random rubble should be made one-third thicker than the thickness necessary for brick walls. Random Rubble Built in Courses. —This consists of stones forming horizontal beds at intervals of 12 to i3 in., every stone being bedded in mortar. The object of coursing is to insure that there shall be no con¬ tinuous vertical joints. To save expense in bedding each stone in mortar, masons bed only the stones on faces of wall, and at these levels pour a pail of thin mortar, called grout, to fill up any cross joints between stones, taking care that the hearting stones are prop¬ erly interlocked. TJncoursed Squared or Snecked Rubble. —Stones roughly squared and hammer or axe faced, the vertical depth of the stones usually being less than 9 in; to prevent continuous long horizontal joints, small stones, termed snecks, are placed at intervals adjacent to a large stone, the beds of both being level and thereby com¬ mencing a horizontal joint at another level. Squared Rubble Built in Courses. —Squared rubble is brought up to level beds with dressed quoins. The coursing is to prevent continuous vertical joints. It is sometimes known as irregular coursed rubble, as the courses need not all be of a uniform depth. Regular Coursed Rubble. —In this kind of work all stones in one course are squared to the same height, usually varying from 4 in. to 9 in., and are generally obtained from thin but regular beds of stone. Block in Course is the name applied to stone walling, chiefly used by engineers in embankment walls, harbor walls, etc., where strength and durability are required. The stones are all squared and brought to good fair joints, the faces usually being hammer-dressed. Block 196 STONEMASONS’ GUIDE in course closely resembles coursed rubble, or ashlar, according to the quality of the work put upon it. Ashlar.—Ashlar is the name applied to stones that are carefully worked, and are usually over 12 in. in depth. As the expense would be too costly to have walls built entirely of ashlar, they are constructed to have ashlar facing and rubble backing, or ashlar facing and brick backing, but, as the backing would have a greater number of joints than the ashlar, the backing should be built in cement mortar, and brought to a level at every bed joint of the ashlar, to insure equality of settlement. The ashlar facing may be plain, rebated, or cham¬ fered, and looks best when laid similar to Flemish bond in brickwork. JOINTS In arranging the joints of masonry the following general principles should be observed: 1. All the bed joints must be arranged at right angles to the pressure coming upon them. 2. Joints should be arranged to prevent any mem¬ bers, such as sills, being under a cross-stress. 3. The joint should be arranged so as to leave no acute angles on either of the pieces joined. The first condition applies to all kinds of masonry. It is necessary to prevent any sliding tendency taking place between the stones. The second condition applies chiefly to sills in win¬ dow openings. These, if in one piece, and built into the piers at each side of the opening, are often sub¬ jected to a cross-stress, owing to the settlement being greater under the piers than beneath the window open- JOINTS 197 ings. This danger occurs more frequently in openings in the lowest story, and the effect of it is to break the sill. In brickwork, this defect is remedied by fixing the sill after the whole of the brickwork has been erected and the settlement taken place; but in stone¬ work, and under conditions where the sill must be fixed as the building proceeds, the breaking of the sill may be prevented by having a vertical joint in the line of the face of the reveal. If there are any heavy mullions down which pressure may be transmitted, the same precaution must be taken with the sill; but if light mullions occur, the sill maybe taken continuously through. In such cases no joint in the sill should occur under the mullions. The third condition applies chiefly to the joints in tracer)'' work, and any exposed joints in any other work. Stone being a granular material, anything approaching an acute angle is liable to weather badly; therefore in any tracery work having several bars intersecting, a stone must be arranged, to contain the intersections and a short length of each bar, and the joints should be ( a ) at right angles to the directions of the abutting bars if straight, or (&) in the directions of a normal to any adjacent curved bar This not only prevents any acute angles occurring, as would be the case if the joints were made along the line of intersec¬ tion of the moulding, but also insures a better finish, as the intersection line can be carved more neatly with the chisel, and is more lasting than would be the case if a mortar joint occurred along the above line. In no case, either in tracery, string courses, or other mould¬ ings, should a joint occur at any miter line. Joints.—These may be classified as follows: I. To resist compression, such as the square joint, 198 STONEMASONS’ GUIDE the surface of which is arranged normal to the pressure. 2. To resist tension, cramps, lead plugs and bolts. 3. To resist sliding or displacement, joggle, joints, tabling dowels and pebbles. Joints to Resist Compression.—Joints in stone under a compressional stress have plane abutting surfaces normal to the stress Joints to Resist Tension.—The texture of stone unsuited to form tensional connections. Where there is any tensional stress the joints are best held together by metal connections. Cramps.—Metal cramps are used to bind work together, and are particularly adapted for positions in which there is a tendency for the stones to come apart, such as in copings covering a gable, or in face stones of no great depth, or cornices and projecting string courses to tie them to the body of the wall. The cramps are made from thin pieces of metal of varying lengths and sectional area according to the work, turned down about 1% in. at each end. The ends are made rough and inserted into dovetailed-shaped mor¬ tises, and the body in a chase made to receive them in the stones to be connected. The cramps are usually prepared from either wrought iron, copper, or bronze. If WiOught iron is used, it is usually subjected to some preservative process, such as tarring and sanding or galvanizing, to prevent oxidation. Iron is useful on account of its great tensile strength. Copper is valued for its non-corrosive properties under ordinary condi¬ tions, and its tensile strength, which is not much less than wrought iron; it is, however, comparatively soft. Bronze possesses all the properties of copper necessary for cramps, and in addition is much harder, and there¬ fore better. JOINTS 199 The best bedding materials are Portland cement, sulphur and sand, asphalt and lead. Care should be taken to completely envelop the cramp in the bedding materials. Stones are also connected by slate cramps set in cement. Lead Plugs. —Stones may be connected together by means of lead in the following manner: Dovetailed- shaped mortices are made to correspond in the side joints of two adjacent stones, into which, when placed in position, molten lead is poured, and when cool is caulked, thus completely filling the mortises and con¬ necting the pieces. Bolts. —Stone pinnacles, finials, and similar members, where built of several stones, are usually connected together with iron bolts passing through all of them and binding down to some more stable portion of the work. Cornices with a great projection are secured by long iron bolts, termed anchor bolts, carried well down into the body of the work, and at their lower ends passing through large iron plates termed anchor plates. Rag Bolts. —Are employed to secure ironwork to stone. The ends of the bolts are often fixed by having the end that is let into the stone jagged, and run with lead, or sulphur and sand, the mortise being dovetailed- shaped to secure it from any upward pressure. Where there is any probability of a great upward stress a hole is drilled right through the stone and a bolt supplied with a washer passed through in the ordinary manner. Joints to Resist Sliding. —The following are those most used: Joggles. —A joggle is a form of joint in which a por¬ tion of the side joint of one stone is cut to form a projection, and a corresponding sinking is made in 200 STONEMASONS’ GUIDE the side of the adjacent stone for the reception of the projection. It is chiefly used in landings to prevent any movement between the stones joined and so retain a level surface between them, and also to assist in distributing any weight over every stone in the landing. Tabling Joints. —This is a form of joint that has been used to prevent lateral motion in the stones of a wall subjected to lateral pressure, such as in a sea-wall. It consists of a joggle joint in the bed joints, the projec¬ tion in this case being about in. in depth and a third of the breadth of the stone in width. This kind of joint is rarely used now, owing to the great expense in forming it, it being superseded for sea-walls by huge blocks of concrete cast on or near the spot, of a weight sufficient to resist any pressure likely to be brought to bear on them, and usually under other con¬ ditions by long slate joggles placed in a space to receive them in the bed joint at the junction of side joints of two stones and the top bed joint of another. Cement Joggles. —These are generally used in the side joints of the top courses of masonry to prevent lateral movement in them, and consist of a V-shaped sinking in the side joint of each adjacent stone in the same course. Dowels. —Doweling is another method of obtaining the same result as joggling or tabling. The dowels consist usually of pieces of hard stone or slate about I in. square in section, and varying from about 2 in. to 5 in. in length, slightly tapering from the center towards the two ends, being sunk and set in cement in cor¬ responding mortises in the adjacent stones. They are used in both the side and bed joints. They are generally employed in the top courses of masonry TOOLS USED IN STONEWORK 2ol where the weight on or of the individual stones is not great. The united mass thus formed from the col¬ lected stones renders any movement impossible under normal conditions. Pebbles. —Small pebbles, owing to the ease with which they may be fitted, were formerly employed in the jo : nts of stones to prevent sliding. They are now in most work displaced by slate dowels or joggles. The pebbles are still sometimes used for small work. TOOLS AND APPLIANCES USED IN CUTTING AND BUILDING STONEWORK The tools used by the mason are many and varied, as different tools are required for different styles of work, and even where the same style of work is being wrought, but being made of softer or harder materials, other sets of tools will be required. Marble and the softer stones are worked with tools that are very much different from those used in working granite or the harder stones. The following tools and appliances are those mostly used at the present time by operative masons: Fig. i. The square is of various sizes, and generally made of steel plate about cne-eighth of an inch thick; the edges are parallel and at right angles to each other. It is important that the square should be true, as the accuracy of the work depends entirely upon it, and for this reason it should be frequently tested for correct¬ ness. Fig. 2. The set square is of several sizes, and made of iron, brass, or zinc plate; it contains a right angle 202 STONEMASONS’ GUIDE rrc / MASONRY 7 S 3 3* Jj TOOLS USED IN STONEWORK 203 and two angles of forty-five degrees, and is used chiefly for miters, and setting out on bed of work. Fig. 3. The bevel, or shift stock, made of iron or brass, and used for sinkings, bevels, etc. Fig. 4. A small tee square of unequal sides, and with right angles, used for sinkings, etc. Fig. 5. Mallet of beech, or other hard wood, of various sizes, for striking the cutting tools. Fig. 6. Hand hammer of steel, about five pounds in weight, used principally with punch for removing waste, and in very hard-grit stones. It is used also with hammer-headed chisels. Fig. 7. The punch; the cutting edge of this tool is about a quarter of an inch wide, and chisel-pointed. It is used with the hammer for removing all super¬ fluous waste. Fig. 8. The point, with edge similar to punch, is used with mallet, generally for hard-grit or lime stones, and for reducing the irregularities left from punch, leaving the stone in narrow ridges and furrows close down to face. Fig. 9. Chisels, of various widths, from % in. to lyi in. wide, used for mouldings, fillets, sinkings, etc. Figs. IO and II. Boasters, from \ Y A in. to 3 in. wide, used for dressing stones down to smooth faces, and cleaning or finishing mouldings, etc. Fig. 12. Broad-tool, about 4 in. wide, used for tooling. Fig. 13. Claw-tool. These are of various sizes, the teeth being cut coarse or fine to suit the texture of the stone. For hard lime stones the teeth at point are about yi in. wide, and for softer stones from ^ to in. wide. The claw tool is used after the punch or point, dressing down the ridges still closer to finished face. 204 STONEMASONS’ GUIDE Figs. 14 and 15. Small chisels, of various sizes, for carving, letter-cutting, etc. Fig. 16. Small chisels, called “splitters,” of various sizes; the heads are concave, or cup-headed, as in sketch, Fig. 38. When used with an iron hammer, Fig. 21, they cut very smooth and sweet. They are used mostly for marble work, carving, lettering, etc. Fig. 17. Pitching tool; this has a beveled instead of a cutting edge, and is used with the hammer, for pitching or knocking off the irregularities or waste lumps on stone. Fig. 18. Jumper, chisel-pointed and slightly round¬ nosed; it is wider at cutting edge than the diameter of tool, so that it clears itself in cutting circular holes, for which it is used, chiefly in granite. P"ig. 19. Chisel for soft stone (this is a general term, and comprises varieties like marble or alabaster). The chisels have wood handles, and are similar to car¬ penters’ “firmer chisels. ” Fig. 20. Drags for soft stone, of best steel saw- plate, with coarse, middling, and fine teeth, called coarse, seconds, and fine drags. These are used by traversing the face of the stone in all directions and removing the saw and chisel marks, and finishing to any degree of smoothness required. Fig. 21. Iron hammer, about three or four pounds weight, used with cup headed tools, for carving, letter¬ ing, etc. Fig. 22. Dummy, of lead or zinc, about three or four pounds in weight, used for striking the soft stone Note—N umbers 8 and 15 are mallet headed tools, and must never be struck with the hammer, the heads being made to receive the blow of the mallet only. TOOLS USED IN STONEWORK 205 tools; it is handier than the mallet, and at times more convenient to use. Fig. 23. Cross-cut saw, of best steel plate, and of various sizes, for cutting soft stone blocks, scantling, etc.; the teeth are coarse, and broadly set for clear¬ ance. Two men are required in using it. Fig. 24. Compasses, for setting-out work, etc. Fig. 25. Shows sketch of a saw frame, for hand¬ sawing, which in practice requires some little skill in framing up to the various sizes. The frame generally, for good working, should be about two feet longer inside than the length of stone to be sawed, so as to allow for draft. The heads or ends of frame are made of 4 x 3 in. pine, tapered from near the top to 3^ x 2 in. at the bottom, with a groove or slot for the saw 4 in. deep by I yl in. wide, the angles being rounded off or smoothed to make it easy for the hands. The stretcher is a piece of pole about 3 in. in diam¬ eter, with iron ferrule at each end, varying in length. Packing "pieces are used against the head at each end of stretcher as shown. The couplings are in wrought iron, ^ in. in diam¬ eter, of various lengths and shapes, as in sketch. These are tightened up with a union screw in the cen¬ ter, which keeps the saw taut, so that no difficulty is experienced in getting the saw frame to the required length. The saw plate is of iron, about 4 in. wide by T V in. thick, with two holes punched through it, %. in. in diameter, at each end, for iron pins, which are inserted to keep the saw in position. The pins are 4 in. long, and have a small slot the thickness of the saw plate and yi in. deep, fixed with the groove towards the end Xj r/tAi /or cou^>Zzr%^ ujb Fratree. 206 STONEMASONS’ GUIDE TOOLS USED IN STONEWORK 207 of the saw; this enables the sawyer to keep the saw straight down the cut, by tapping either end of the pin, should the saw deviate from' the vertical line. This slot in the pins is important, as the saw cannot be kept true without this arrangement. The pole, for carrying the saw frame, is from 16 to 20 ft. long and 3 or 4 in. diameter at bottom, and tapering towards the top; a crosspiece and chain is secured nearly at the top of pole to carry the pulley. The pole is kept in position by planting it in the ground, and a rough piece or two of stone is laid against it. The cords for carry¬ ing the saw frame are about ^ in. in diameter; small chains are sometimes used, but cords work more easily. The cord is fastened round the stretcher and over the pulleys on top of the pole (which must be vertical to the cut), and then round hook of bottom pulley. The weight must be so adjusted as to allow the saw- frame to be the heavier by about eight or ten pounds; this, however, will depend greatly on the nature of the stone. The position of weight can be raised or low¬ ered to suit the cut by shifting the cord at the bottom of the pole. The drip board is of pine, as in sketch, and about 2 ft. long, with sloping side against the cut, and on this is placed the water tub; a small spigot is inserted in the bottom of the tub, and is adjusted to allow the water to trickle down the board, carrying with it the sand, which is also on the board, into the cut. To regulate the supply of water and sand, the sawyer uses a small rake with a long handle. The line of cut for saw should be set out with a plumb rule or bob at each end of the block, and a V-shaped chase cut in to guide the sawyer in keeping to a true line. 208 STONEMASONS’ GUIDE The best sand for cutting is hard grit, washed through several sieves, all the coarse and fine being rejected, and the medium size only used. A bushel of this sand will cut about 12 ft. super of stone. The saw is drawn backwards and forwards and the stone cut by the attrition of the saw plate with the sand and water. A good sawyer can cut by hand from 15 to 20 ft. super of sandstone in one day of ten hours. On large jobs steam stone saw frames are used, in which, if necessary, from one to twenty cuts may be put in one block at the same time. Fig. 27. Shows a method of coping or splitting a block of stone to a required size. Begin by cutting a V chase on top and two sides of the block, as at g, f e\ directly under this place a wood skid, and on the top of the skid a long iron bar, which should bone with the lin z gf\ or a punch driven in on each side, as at e, will do nearly as well. At extreme end place a short skid, as at /z, and packed up to within an inch of the under side of the block. This is done to prevent the coped piece from breaking under by its own weight, as the fracture would not take the line of direction proposed, but would prob¬ ably break away from j to k and spoil the block. Sink wedge holes with the punch (at distances apart varying with the nature of the stone) to as fine a point as possible at the bottom of the hole, as in sketch, at b, so that the wedge will bite or hold when struck with the hammer. The apex of the wedge, which is of iron, is blunt pointed and about % in. wide, so that it does not touch the bottom of the hole, or when struck it would jump out. The holes being cut, the wedges are inserted in each one; care must, however, be taken TOOLS USED IN STONEWORK 209 to keep them upright, so that the cleavage takes the line of direction required. The wedges are now gently tapped with a heavy hammer, till all have got a hold; then harder blows are given in quick succes¬ sion, and the fracture takes place. a shows sketch of wedge, made of iron, and from 4 to 5 in. long and in. wide. In coping or splitting granite, wedge holes are not cut as in stone, but circular holes are “jumped,” 1 in. or 1 % in. in diameter and about 5 in. deep, at dis¬ tances apart varying with the obstinacy of the mate¬ rial, and plugs and feathers are inserted and driven in as for stone. The plug is of soft steel, and made tapering as at c . The feathers are thin pieces of iron, concave in sec¬ tion, as shown at c 1. These are first put in the holes, the plugs are then driven in until they become tight, and a few sharp blows are all that is necessary to com¬ plete the process of splitting, c 1 is a plan of c to a larger size. Fig. 28 shows a pair of iron lewises used in lifting worked stones for fixing. The lewis consists of a dovetail of three pieces, the two outer pieces being first inserted in the hole, and then the center piece, which acts as a key, and tightens up the dovetail; the shackle is next put on, and the bolt is passed through the whole. Care must be taken to cut the hole to a dovetailed shape, and of the size of the lewis. A is the front view and B is the side view, of the lewises. Fig. 29. Shows an iron conical-shaped lewis plug, which is placed in a slightly larger dovetailed hole, a small curved iron plug being inserted by its side, 210 STONEMASONS’ GUIDE which keys it up. This is used chiefly for worked granite. Fig. 30. A pair of chain lewises, consisting of two curved iron plugs with rings for chain; these are inserted in a dovetailed hole, and when tightened up act similarly to the ordinary lewises. Fig. 31. A pair of iron dogs, or nippers, with steel- jointed claws, used for lifting rough blocks, and also for fixing. Fig. 32. Axe, about 12 or 14 lbs. in weight, chisel- pointed, used on granite for removing the inequalities left by the pick and dressing it similarly to tooled work in stone, showing the marks or indents in paral¬ lel lines. Fig. 33. Pick, about 16 lbs. weight, used chiefly on granite, for dressing the inequalities of the rough or rock face down to within 1 in. of the finished face; and also used for scabbling blocks of stone roughly to the required shape. Fig. 34. Spalling hammer, about 12 to 14 lbs. weight. This has a square edge of about 1^ in., and is a very effectual tool for knocking off rough lumps. Fig. 35. Patent axe; the body of this is of iron, with a slot at each end, into which a number of parallel thin plates of steel, chisel-sharpened and of equal length, are inserted and tightly bolted together. This is used for granite, and produces the finest description of face, next to polishing. Fig. 36. A pair of trammel heads, or beam com¬ passes, used chiefly for setting out arcs of circles full size; those made of gun-metal, with steel points, are the best, and a set should be large enough to take a rod 30 ft. long. Fig. 37. A spirit level for fixing. TOOLS USED IN STONEWORK 211 Tram m cl KcclcIa k Root COP/AfC on S PLITTI N C BLOCK BY WEDGES 212 STONEMASONS’ GUIDE The following appliances are also required for set¬ ting out work: A large platform or drawing board, about 10 or 12 ft. square; or if larger than this, the better. It maybe fixed either vertically or horizontally. A standard five-foot rod. Two or three straight-edges of various lengths. Pine rods for story rods, and for setting out lengths of cornices, modillions, dentils, etc. Pipe-clay and stiff brush, for cleaning off board, rods, etc. Sheet zinc for moulds, usually No. 9 gauge, this being a good workable thickness. The lines for face, bed, and section moulds have to be carefully trans¬ ferred to the sheet zinc, and cut to their proper contour or shapes with'shears and files. The foregoing lists do not comprise all the tools and appliances required for every branch of masonry, but only those which are in common use. All cutting tools are made of the best cast steel, except the pick, axe, and spalling hammer, which are sometimes of iron, steel pointed and faced. NAMES OF WROUGHT STONE There are three classes of stones made use of for building purposes; namely, rough stones as they are taken from the quarry, stones squared and dressed in a rough manner, stones dressed and squared accurately. Stones, rough and left unsquared, are called “rub¬ ble.” When stones are roughly squared and dressed, they may be “quarry faced”; that is, the face is left just as it came from the quarry; or it may be “pitched faced,” or “rock faced,” in which case the face will NAMES OF WROUGHT STONE 213 B project beyond the face of the joint; or it may be “drafted,” in which the face is surrounded with a chisel draft to allow of the joints being flush on the face. In cut and dressed stones, there are: 1, the rough pointed; 2, the fine pointed; 3, the crandaled; 4, the tooth axed; 5, bush hammered; 6, rubbed; 7, diamond paneled. There are also other finished stones, that will be discussed in future pages. The illustrations (Fig. 39) show the different stones when finished. These exhibit the various forms of dressing stone commonly used. A shows a boasted or chiseled face, sometimes termed droved work. The face is finished with a boaster, and the strokes are generally regular and parallel to each other. In hard-grit stones this face is usually left as finished, and when, as in the case of a building, the whole of the ashlar and plain work is chiseled to the same angle of inclination, the effect is pleasing. In softer stones a finished face is formed by rubbing the boasted face with sand and water, and removing all chisel marks; it is then called plain ashlar. F 1 Fig- 39 - B shows ashlar with tooled face. 214 STONEMASONS’ GUIDE This is formed with a broad tool, or wide boaster, by a regular succession of strokes, parallel to each other, extending across the whole width of stone, and when finished shows a series of flutes or channels, the size of flutes depending on the texture of the stone. Considerable skill is required in tooling neatly, and the tooling is somewhat costly, the surface having first to be worked to a boasted face. C shows ashlar with pick or pecked face, and tooled margin. This is produced with a point, or in the case of granite with the pick, and can be worked to any degree of fineness. D shows ashlar with punched rock face, and tooled margin. This is similar to the last mentioned, but much coarser. In producing it, the punch is driven in almost vertical to the face until the stone bursts out, leaving a series of cavities. When regularly done it looks well, and is very effective, and for large work it gives the appearance of boldness and solidity. E shows ashlar with broached tace, and tooled margin. This is produced with a point, which forms a furrow with rough ridges, and is worked across the stone to the required angle. F shows ashlar with rusticated face, and tooled margin. This is worked with small chisels and points, and sunk down about half an inch, leaving a plain, narrow margin on face; the pattern is irregular, but easily adapted to any space. G is a rebated or rustic quoin, with vermiculated face. NAMES OF WROUGHT STONE 215 This is cut out with small chisels, and has the appearance of being worm-eaten. In order to prepare the stones for dress finishing they must first be brought to a flat surface on one side. This flat surface or face may be “winding,” or it may be a plain, flat surface similar to that shown in Figs. 40 and 41. When the bed, or one plane surface, has been produced, the required shape of the sides of the block are marked upon the surface with the aid of a square or tem¬ plate. Drafts are then sunk by the chisel across the extremities of an adja¬ cent face with the aid of a square (Fig. 40), or bevel if the sides are not to be at right angles to the bed, and a second face is obtained between such drafts. The process is repeated for the third face, and so on, until the block has been brought to the de¬ sired form. Regularly winding surfaces may be ob¬ tained in various ways. The simplest plan is when the stone is worked to the proper planes and angles, as just described, to set off the amount of the winding, Aa, Fig. 42, on the arris and draw the drafts, lines #B, aC. A series of lines, as be , cf dg , are then drawn parallel Fig. 41- Fig. 40 . 2 l6 STONEMASONS’ GUIDE Fig. 42 . with A a, and another series, eh, ft, gk, parallel to AC. The drafts being sunk at these, so that a straight edge coincides from b to h, or c to i, or d to k, the surface is wrought so that when the rule is applied parallel to the plane A a B, it may coincide with the sur¬ face at every point. If one end of the stone is less in length than the other, (Fig. 43), the line aB must be divided into equal parts, and the lines be, ef dg, drawn parallel to A a. The line CD is then divided into the same number of equal parts in h, i, k\ then ch, fi, gk are joined in¬ stead of being drawn parallel to AC. The drafts are then sunk until a straight edge agrees from b to h, and 0 so on, and then the sur¬ face is dressed so that 8 the straight edge will coincide in a direction parallel to the plane A a B. Winding surfaces may likewise be formed by the use of two rules, one having parallel and the other divergent edges. These are sunk in drafts across the two ends of Fig. 43- the stone until their upper edges are out of winding. The ends of these drafts are then connected by means NAMES OF WROUGHT STONE 217 of two others formed along the sides of the block, and the entire surface worked down to them until it coincides with a straight-edge placed in a direc¬ tion parallel to the drafts. The rules used in this proc¬ ess are known as “twisting rules,” one of which, as at A, Fig. 44, is, of course, simply a straight edge with parallel to opposite edges. The other, B, is termed a “winding strip,” and that portion of it which coincides with the twist of the stone, as shown by the dotted lines, is, of necessity, a triangle. The formation of mouldings, columns and the work of the carver and sculptor, as well as that of the marble mason and statuary, form a spe¬ cial branch of the trade, which com¬ prises the production of such parts as enriched cor¬ nices, capitals, etc., and is necessarily valued by the time expended upon it; the value of the time varying, in the higher class of carvings, with the artistic repu¬ tation of the man employed, and, as this work is not intended to teach the higher artistic phases of the art of masonry, such matter will be left to be dealt with in another volume that may follow this in the near future. The wall mason builds all stone constructions and, from the irregular shapes and sizes of the mate¬ rials generally at his command for building purposes, is constantly called upon to exercise an amount of judgment and skill far beyond what is required to make a good bricklayer, who mostly lays his regular¬ shaped bricks according to fixed rules, which he knows 218 STONEMASONS’ GUIDE by heart, and ought not to depart from. The rougher the materials, the more skill is required in putting them together; whilst the greater the labor expended in dressing them to regular shapes, the easier is the task the wall mason has to perform. Large face moulds are sometimes made of several pieces of timber framed together. When the beds of the courses are to be plane and level they can be set correctly by the level and com¬ mon straight-edge. When they are to be planes hav¬ ing a given shape a rule must be employed having two straight edges inclined to each other at such an angle that, when one edge is set horizontal by the spirit- level, the other has the proper inclination. If the beds of the courses are to be perpendicular to a straight or curved battering face, their position can be set out and tested by the square. Curved beds, such as are employed for some special purposes, require the use of suitably curved bed moulds. In all cases in which economy of time and money has to be studied, the workman should, as far as prac¬ ticable, avoid curved figures in masonry; for not only are they more tedious and expensive to set out, and to build than straight and plane figures, but it is more difficult to test the accuracy with which they have been executed. A single glance will detect the small¬ est appreciable inaccuracy in a wall with a straight batter, while the same process in the case of a wall with a curved batter, would require either a long series of measurements, or the application of cumbrous face-mould to various parts of the wall; and this becomes a matter of serious importance in large struc¬ tures, where errors in form may affect the strength and stability. NAMES OF WROUGHT STONE 219 All stones, except under peculiar circumstances, should be laid on their natural or quarry beds , or with their natural beds as far as possible perpendicular to the pressure they have to bear. The strength and durability of the stone depends on this being done — even in cases in which the natural beds cannot be dis¬ tinguished by an unpracticed eye—for few stones will bear the same pressure applied in the direction of their lines of stratification as at right angles to them; more¬ over, if the bed of a stone is exposed on the face of a wall, the water will get in between its layers, and frost will soon cause layer after layer to peel off; hence it follows that in projecting undercut mouldings and weathered coping the natural beds should be placed parallel to the side-joints. The careful bonding of the masonry must be attended to. A wall built of the roughest stones ought to be perfectly stable, though no mortar is used. The principles of bond, by the stones overlapping and breaking joint throughout the wall, are the same as in brickwork, and should be thoroughly understood by the mason, for upon their skillful application his reputation as a good waller depends. All dry and porous stones should be well wetted before being laid in mortar, so as to absorb the mois¬ ture required for the proper setting of the mortar. All joints should be filled up solid with mortar. The thickness of the bed-joints, depending on the smoothness of the beds, must be sufficient to prevent any unequal bearing resulting from actual contact between any irregularities on them. Where a good appearance is aimed at, all stones exposed to view should be selected free from stains, chiefly caused by oxides of iron. 220 STONEMASONS’ GUIDE Iron should never be placed in contact with stone¬ work where, by rusting, it might disfigure it with stains, or split the stone by its increase in bulk during the process of oxidation, or by its expanding and con¬ tracting under the influence of heat and cold. In order to understand the practical operations of building in stone, it is necessary to explain the differ¬ ent descriptions of masonry in ordinary use. These may, as before explained, be included under one of the three following heads, viz.: Rubble, Block-in- course, Ashlar. If the stone at disposal is thinly bedded, rough or intractable, it should be used as rubble-work; if obtain¬ able in blocks, and more or less easily wrought, it should be used as block-i?i-course, or ashlar , according to circumstances. RUBBLE MASONRY In rubble-work stones of irregular size and shape are laid in a wall, after having been more or less assorted, roughly shaped to fit one against another, and hammer- dressed on their faces with the waller’s hammer, according to the quality of the work required. In the rougher kinds of rubble-work no selecting of the stones takes place, but the waller, having once taken one up, places it in the wall as it will lie best, pack¬ ing in smaller stones between the larger ones. The stones should be placed on their best beds, and not on their points, which would be liable to crush, in addi¬ tion to the wedge-like action of such stone, in the interior of a wall, tending to dislodge the facework. No attention whatever is paid to the joints being more horizontal or vertical than naturally results from the bedding and cleavage of the stone used, upon which RUBBLE MASONRY 221 the degree of regularity in the appearance of the work mainly depends. In rubble masonry the rough nature of the work leaves many spaces between the joints, both on the face and interior of the wall; these should be carefully packed up or pinned with spalls, which are the pieces knocked off the rougher stones in order to get them to fit into place. Care should be taken that the hearting or interior of a rubble wall is well packed with spalls and mortar, Fig. 45. and not left full of hollows or mortar alone; to ascer¬ tain whether this has been done, take the waller’s trowel and plunge it in different places into the heart of the wall. The spalls must not be placed in the heart of the wall so as to drive like wedges when the weight from above comes on them, or the facing stones will be forced out. Attention is necessary during the building of rubble, as well as all masonry walls, to insure their being well bonded transversely, and not built up with two thin 222 STONEMASONS’ GUIDE of c-y ^ S' '/ '' "4f s y /< / s/S />■ , 4 ? S' S/ # / scales on each face, tied together by through stones, with the core or hearting merely filled in with small pieces. This is a very common fault with masons, who will rely upon the mortar to give stability to a wall which, without it, would fall to pieces under its own weight. The best stones for rubble. masonry are those that scabble freely, and such as lie in 4 or 5-inch beds. Basalts and stones of a crystalline structure are troublesome to use, as they fly under the hammer, but granite and sandstones work in well. Rubble may be either uncoursed, irregidar or random coursed , worked up to courses , or coursed , chiefly de¬ pending upon the character of the stone at disposal. Some stones, from their intractable nature, and the absence of any distinct lines of bed¬ ding, are especially adapted for uncoursed rubble (Fig. 45), whilst other stones have lines of layers or courses and therefore should be used in square rubble, as shown in Fig. 46. A portion of a structure in random rubble is shown 0% s s $ y t < t r^- //X ,/ //// A tys, y, / ' /// '// A' /// /// Fig. 46 . RUBBLE MASONRY 223 in Fig. 47. This shows the quoins or corners in vari¬ ously finished stones, all of which are named on the illustrations. Random, common or rough rubble, built up to courses, is indicated in Fig. 48; the courses vary in depth from 12 to 18 inches. The remarks made above apply to this discription. Square uncoursed, random coursed, irregular coursed, snecked or squared rubble, are five names implying practically the same description of work. It is shown in Fig. 49, A. There is a certain amount of coursing, but it is not regular or continuous; jumpers are used, but no spalls, and, if careful attention can be 224 STONEMASONS’ GUIDE given to bond, the strength of the wall is considerable. Random with hammer-dressed joints and no spalls on face, or close-pricked polygonal ragwork, often called “cobweb” rubble, is shown in Fig. 49, C. Joints lie in all directions and considerable skill and experi¬ ence are required to make good work. Freestone is seldom used in this description of walling, as it is chiefly formed with broken .boulders, or field stones that have been split apart by dynamite or other explosives. O O 26 J6 *6 60 r^ r — ■ 1 - - - , ■ ■ , ■ ■ ■ i - » • » Fig. 48. Regular coursed rubble (Fig. 49, D) — a very perfect bond can be obtained in this class of work. The courses often vary in depth, but are seldom more than 9 or 10 inches deep. Good stone found in thin beds in the quarry is commonly used. Joints in any of these examples may be galleted by driving into them, from the face, chips of flint or hard stone. Technical terms in connection with walling differ so much in different parts of the country that it is often advisable to build a small sample for reference in pricing quantities. In the rougher descriptions of rubblework, lacing RUBBLE MASONRY 225 courses are used to give the wall additional cohesive strength; they are two or more well-bonded courses of masonry or brickwork laid at short vertical intervals. Block in course, or hammer-dressed ashlar (Figs. 50, A, and 51, A), is intermediate between the best rubble and ashlar. The coursing is regular, and the Fig. 49. blocks are roughly squared; it is frequently constructed of shoddies, which are sound stones less than 12 inches deep. The length of each stone should be from three to five times its depth, and the breadth from one and a half to twice its depth. The exact proportions depend on the degree of resistance which the stone offers to 226 STONEMASONS’ GUIDE cross breaking. The same rules as to proportions apply to ashlar work Ashlar is in large blocks, squared and regular in size, laid in courses varying in depth from about io to about 14 inches; the bed joints should be out of winding, but not smooth, and should never be worked slack (hollow on bed) and underpinned with spalls, as in Fig. 55,B; such a practice concentrates the weight on a small area, and leads to crushing or to the joints flushing, that is, the arrises breaking. Joints should be as thin as the class of work allows, but never so as to leave an insufficient cushion of mor¬ tar to spread the pressure over the whole joint, as this would lead to flushed joints. Sheet lead has Fig. 51, A. 1, . ;- t I 1 1 ( \ -^-— Fig. 51,B. Fig. 52,B. been inserted in joints subject to great pressure, to equalize it; but it is found that it squeezes outward and flushes the joints, thus more than counterbalancing any good it may do. When the courses throughout the face of the build- RUBBLE MASONRY 227 ing are all of the same depth, the ashlar is regular coursed (Figs. 52 and 53). If they vary in depth, it is irregular coursed; if the courses are not continuous, but broken, it is random ashlar, but the last class of BLOCKING CO work is unusual. The bond adopted follows the general idea of Flemish, but as all stones are not of the same size, considerable freedom is allowed in bonding, and, except in the best class of work, no attempt is made to keep the perpends. The courses should range with the quoin stones and dressings. Joints can be made less than one-eighth inch thick. Plasterer’s putty is frequently used to make the outer part of the joint; it extends inward about two inches. Before being set, each stone PI AN OF 3AD01 £ JOINT Figs. 52 and 53. \SADPU BACK C 1— ■ 1 ... 1 I 1" 1 Fig. 53 .A. is laid dry in its place to ascertain that it truly fits. The amount of work on the face of ashlar varies very considerably; a drafted margin round a rough face is the minimum. 228 STONEMASONS’ GUIDE Rebated joints and V-joints are shown in Figs, 55 *^* 54,B, and 55, B. They are used to emphasize the joints, and at the same time they prevent them from flushing. Ashlar, so treated, is called rusticated. A wall built of solid ashlar is necessarily costly, and the term has come almost to imply a facing of ashlar with a backing of rubble or brickwork. The ashlar is often only four inches and seldom more than six inches (thick, with bond stones projecting into the backing. Fig. 55,A. Fig. 55 ,B. Fig. 54,B. Figs. 52 and 53, A, show examples of brick ashlar and rubble ashlar. The ashlar should average about 8 inches on the bed, and should bond transversely with the backing. Headers of a length at least two-thirds of the thickness of the wall should be laid, one to every superficial yard of face. The backing, if of rubble, should be built in courses, each leveled up to RUBBLE MASONRY 229 coincide with the ashlar courses. If of brick, the ashlar courses must be of suitable depth to allow of the same treatment. The greater number and greater thickness of the joints in the rubble or brickwork lead to more compression in the backing than in the facing, and this tends to cause the wall to bulge outward. This effect can be to a large extent avoided by building in cement or a quick setting mortar. Badly built walls of this description are very liable to collapse in case of fire, owing to the differing behavior under heat of the back and face. Some may be roughly squared at the quarry; it is then said to be hammer dressed or quarry pitched. Afterward it is sawed to size, half sawing being charged to each of the two blocks produced by one cut. Saw¬ ing is now largely done by machinery. Plain work is the labor on a stone to “take it out of winding,” or reduce it to a plane surface. Half plain work is simi¬ lar, but is more roughly done, as for beds and joints. Self faced, natural faced, rock faced, are terms all of the. same meaning, and indicate that the face of the stone is left rough as from the quarry, though it may have been scabbled with the hammer to remove irregu¬ lar projections. A wall built of natural faced stone sometimes is called rustic face (see quoin stone in Fig. 47), but it must not be confounded with the rusticated joints mentioned above. A stone is taken out of winding by cutting with ihe chisel a drafted margin along each edge of its face, as shown, and by means of a straight-edge bringing them all into a plane; the intervening space is then worked down to the same plane. If the plane surface be obtained by means of a point instead of a chisel, it is called pointed work; the drafted margin is, how- 230 STONEMASONS’ GUIDE ever, first made with the chisel. When the chisel marks are parallel and regular, but not continuous it is called boasted or droved work; when they are parallel, regular, and continuous, it is. called tooled work. Stroked work is similar to the last, but the lines make an angle of 45 degrees with the-edge. Soft stones are taken out of winding with a comb or drag, which often is merely a piece of a joiner’s saw. Rubbed work is plain work rubbed to a smooth sur¬ face; a rub stone is used with sand and water for this purpose. Some stones, such as marble, can afterwards be polished to a glassy surface. Vermiculated work is indicated in Fig. 39. Sunk work is any cutting below the plain surface, as in rebating or weatherings. Circular work is the labor required to form convex sur¬ faces, as the shafts of columns. Circular sunk work is the labor required to form concave surfaces, as in stone channels. Circular circular work is the labor required to form such a surface as a sphere or a basin¬ shaped hollow. Moulded work is when a moulding of any profile is worked on the edge of a stone, as the cornice in Figs. 49 and 52. Circular moulded work is, in bills of quantities, always kept separate from straight, and is charged at a higher rate. Work is called stopped when the labor, whether sunk or moulded, is not continuous to the end of the stone, as the chamfer on the stone head in Fig. 49. Quoins may be built of larger or differently worked stones from the remainder of the wall. A brick quoin may be built to a rubble wall, and more rarely to ashlar work, as in Fig. 51. In some varieties of rubble it is almost impossible to construct a sound quoin unless material superior to the bulk of the wall be used. Ashlar work is constantly used for the dressings to RUBBLE MASONRY 231 windows and doors in brick and rubble walls; Fig. 47 is an example. Reveals with recesses may be formed as in Figs. 50 and 51. Stone window-sills for sashes and casements should be set to project about 2 inches from the wall face; they are weathered and throated, so that rain-water may run off the surface and drop clear of the wall beneath. They may be moulded on the front, and stools are worked on the ends for the brick or stone jambs to rest on. To prevent water from being blown in between the stone sill and the wood sill resting on it, a water- tongue, usually of galvanized iron, iy& in. by % in., is set in a groove in the stone and wood; it and the wood sill should be bedded on the stone with white lead ground in oil. If sills are set flush with the wall, a separate drip mould (Fig. 47) should be fixed imme¬ diately below to serve the purpose of a throating. Window-heads are made as wide on the bed as the reveal; the head of frame is behind them, with lintel (with or without relieving arch) over. A separate drip mould over the head, as in Fig. 47, protects it from water stains from above. Coping stones are made in many forms, and are often handsomely moulded. As their purpose is to keep wet out of the wall, they should be chosen as nearly impervious to moisture as may be, cut in long lengths, say 5 feet or so, to reduce the number of joints, weathered and throated, and set and jointed in cement. These are respectively parallel saddle-back, and feather-edge coping; the first should only be used in inclined situations, as on gable walls. Raking copings are prevented from sliding by dowels built into the bed on which they rest. The same object ; s 232 STONEMASONS’ GUIDE served by kneelers, which are coping stones provided with horizontal tails (Fig. 47). There may be several of these in a large gable. Those at the foot are some¬ times in the form of corbels (Fig. 47), when they are called skew corbels. The large triangular stone at the head of a gable (Fig. 47) is variously called summer stone, saddle stone, or ridge stone. A cornice at the head of a wall (Figs. 49 and 52) may be one or more stones in height, moulded in front, and weathered and throated. There should always be sufficient tail weight for the stone to rest in its place without the assistance of the cement mortar in which it is bedded and jointed. Vertical cramps, say 2 in. by in., 4 or 5 feet long, and one to each length of stone, or a blocking course, may be added to increase the stability. In addition to mortar or cement, special connec¬ tions, such as cramps, dowels and joggles, may be adopted for binding stones together; these terms are used rather loosely and sometimes interchangeably. A cramp is a connecting piece of metal, slate, or hard stone, so shaped that it holds two stones together. A dowel is a short, thick pin or narrow plate of metal, slate or stone, fitting into two sockets; it is sometimes called a plug, especially when fixed in the bed joint, or when it is formed by running molten lead into a dowel hole. Joggle is a comprehensive term, and include^ all cases where a projection on one stone fits a cor¬ responding sinking in the next. Regular coursed rubble, as shown in Fig. 56, is applicable where the beds, though thin, are pretty regular, so that a sufficient number of stones of a uni¬ form depth can be got to allow of their being laid in regular courses of one stone only in depth. RUBBLE MASONRY 233 Dry rubble walling is the simplest class of rubole work, and consists of stones roughly hammered, and bedded by pinning spalls, without any mortar. It requires considerable skill to lay a wall up of this kind and keep it up straight and fair on both exteriors. i lll | " ; "ill, lllil" 1 ; ililhhiji' 1 ' "ill,.II' 1, fl . -■■■■■I ■jiir.il 1 Jii 1:^ jil iii'illi" ( t H il! ' I. !' '• 1.1 ifii'-l 1 1 1 1 j . . ■% 1 ll,i. 'HIvU 11 iii 11,1 Li i! # 'i'",/ "■•i:;. . . . , « 'VI 'l;l it H'i (y ' ,, 1 | 1 |||' 1111 , 1 " ml 1 1 1 1 1 If|l- .'ll'"I '"I||T l , ill"' | l|l.' .Mull'll' 1 * 'll- 'Ml' 1 ' I '' 1 llllllf . 1 1 "Mi,* ! Is: ij„iii mu Dili in to„ji,niiiiii n ll.. ,| l l '„illll ' , C| 111 ililV .mi ““ .11 :!!’ ""ill!, 'Kiiii !, '.;ii in III /''fll II Fig- 56 . This kind of a wall should be wider at the base than at the top or coping. They are generally built to lines strained through trestles or horses, as shown in Fig. 57. This saves much time, as it avoids the necessity of plumbing the faces. Dry rubble walling is generally built in courses about Fig. 57. 12 inches high, and should have a water proof top, or coping, to keep the water from getting into the body of the work and bursting it in frosty weather. The coping may be made of stones laid on edge in mortar (Fig. 58) of bituminous concrete, or, for want of any¬ thing better, clay puddle, or even sods. 2.34 STONEMASONS’ GUIDE Rubble ashlar consists of an ashlar stone face with rubble backing (Fig. 59), and is subject, even to a still greater extent than brick ashlar, to the evils caused by unequal settlement. To avoid these evils, the stones and joints of the rubble backing should, as before mentioned, be . made as nearly as possible of the same thickness as those -in the ashlar facing, or, if the joints are necessarily thicker, there should be fewer of them, so that the total quantity of mortar in the backing and face may be about the same. This can seldom be economically arranged in practice, but it should be re¬ membered that the more numerous and coarser the rubble joints, the worse the construction be¬ comes. The ashlar should be bonded in with through stones or “headers,” as pre¬ viously described; their vertical joints should be carefully dressed for some distance in from the face, and their beds should be level throughout; the back joint and sides of die tails of the stones may, however, be left Fig- 59 - RUBBLE MASONRY 235 Fig. 60. rough; the latter may even taper in plan with advan¬ tage, and they should extend into the wall for unequal distances, so as to make a good bond with the rubble, the headers from which should reach well in between the bond stones of the ashlar. Through stones may be omitted altogether, headers being inserted at intervals on each side, extending about two-thirds across the thick¬ ness of the wall. Care must be taken that the stones in the ashlar fac¬ ing have a depth of bed at least equal to the height of the stone. In common work the facing often consists merely of slabs of stone hav¬ ing not more than from 4 to 6 inches bed, with a thin scale of rubble on the opposite side, the interval being filled in with small rubbish, or by a large quantity of mor¬ tar, which has been known to bulge the wall by its hydro¬ static pressure. The ashlar facing is in all respects, except those above mentioned, built as described in the sec¬ tion on ashlar, and the backing may be of random rubble done in courses from 10 to 14 inches high, 1 _ ■ t /Vi 1/ As .2 1 ^ Y f'H) P!g. 61. 236 STONEMASONS’ GUIDE according to the depth of the stones in the facing. The illustration, Fig. 59, shows the section of a wall 3 feet thick, with an ashlar facing composed of good substantial stone. Irregular rubble, as before stated, is built up with split boulders, and when finished has an appearance as shown at Fig. 60. When a good face is formed and nice joints made, this kind of walling presents a very fine appearance. Fig. 62. Coarse rubble without dressed quoins has an appear¬ ance similar to that shown in Fig. 61. Snecked rubble is a method of building in which almost any size of dressed stones may be used. The stones marked Fig. 62, are jumpers, B are bonders, and S are snecks. Jumpers must not be used too freely in a wall of this description, or the wall will collapse, especially if any great weight is placed on the top of RUBBLE MASONRY 237 the wall. Bonders should be even/y distributed throughout the whole wall in order to strengthen it, the name bonder showing that the stone goes through the wall to the inner face. Snecks, which determine the name of the wall, should be built in as often as possible. In a block joint two stones are butted against two stones, or two stones are butted against three stones (Fig. 63); or the stones are butted against each other without any attempt at bonding or breaking the joints. rH 1 1 1 1 1 1 1 Fig. 64. \ 1 TJ— 2 L 2 3 Fig. 63. -1 1 1—r 1 . 11 1 r 11 1 1 In Fig. 64 a common arrangement with single snecks beside each jumper is shown. In engineering works on a large scale, this is frequently done where a masonry wall has to resist forces likely to overturn, or having a tendency to overturn, the whole mass, or a part of it. It is claimed that the snecked work is stronger than coursed work, inasmuch as each jumper forms a vertical tie between two courses, and tends to prevent a too long horizontal course from yielding as a hinge. Some engineers seem to consider that single snecks place the jumpers too near to one another, and thus probably form a diagonal line of rupture. An arrange¬ ment like Fig. 65 may thus be preferred by some, giv- 1 "T" 1 1 r—r. 1 1 t 1 i 1 1 | J 1 L Fig. 65. 238 STONEMASONS’ GUIDE ing a short course instead of a single sneck between each pair of jumpers. Several of the vertical joints in Fig. 65, are badly arranged, tending to become perpends. Joints nearly vertical over one another should be separated either by a jumper or, if at all possible, by two ordinary courses. A fault of some of the work executed is that it seems more like brickwork than masonry. There ought never to be the rigid regularity of brick bond in the face of a masonry wall. The regular irregularity— if we may so term it—of a well-built wall shows the skill of the craftsman, and is even appreciated by those able to judge as the correct placing and true economy of every cubic inch of material which the workman has had at his disposal. Bond.—The best bond in masonry is that which shows on the face of the work alternate headers and stretchers in each course, as in Flemish bond in brick¬ work, each header coming over the center of a stretcher in the course below. In such work one-third of the face consists of headers, if the length of the stretchers is twice the breadth of the headers; but as stones are rarely cut to exactly the same dimensions, it may be laid down that not less than one-fourth of the face of the wall should consist of headers and that the stones should break joint from once to one and a half times the depth of the course. Joints.—The thickness of the joint will vary from one-half to one-eighth of an inch, according to the smoothness of, or amount of work bestowed upon, the beds, as it must be sufficient to transmit the pressures from stone to stone, without permitting of actual con¬ tact at any point of their surfaces. The mason’s joint, RUBBLE MASONRY 239 or a properly struck joint, is the best which can be used. Flush Joints.—Care should be taken to prevent the use of flush joints, which are formed by hollowing the beds below the plane of the chisel draughts run round the edges. This was sometimes done by the Greeks, in order to get perfectly close joints; but, by throwing all the pressure on the edges of the stones, they fre¬ quently splinter off and spoil the look of the work. As flush joints cannot be detected after the stones are laid, the masons must be well looked after while at work upon them. With a view of guarding against the splintering, or spalling , of the arrises of cut stonework, as in columns carrying heavy weights, seven or eight pounds sheet- lead is frequently placed between the stones. The lead, which is not allowed to reach within less than one inch of the edges of the stones, is thought to equalize the pressure over the beds by yielding to any slight irregularities on them, but the use of lead instead of mortar is a great mistake. It has been found that stones bedded on thin pieces of pine, instead of lead, equal in area to the bed-joint, bore a greater crushing force than stones double their sectional area bedded on lead in the usual way. The lead which had been used showed no signs of accommodating itself to the irregularities of the beds. The joints of stone columns are often raked out about one inch deep, and pointed up when there is no longer any fear of their settling. The arrises of stones are also prevented from spalling by cutting them back, though this is generally done merely to give a bolder effect to certain parts, such as the quoins and lower stones of buildings. 240 STONEMASONS' GUIDE Open Joints. —Open joints, resulting from projections beyond the plane of the chisel draughts, must also be avoided, especially in the beds, as tending to dis¬ tribute the pressure unequally over them. Rusticated Joints. —Rustic work properly applies to facework left rough from the hammer, though it also applies to a debased class of masonry, picked into deep holes, or honeycombed all over, to give a rough effect; but the term rustication, or rusticated, is also much used to denote masonry in which the joints are either chamfered, or sunk square below the facework. Saddle or Water-Joints.— In addition to the slop : ng off or weathering of the upper surfaces of stonework exposed to the rain, as in coping , cornices, and string coyrses, it is well to saddle the joints, by leaving them rather higher than the rest of the work, as in Fig. 66, in order to throw the rain away from the joints, and so prevent any water finding its way through them, and down the face of the work. Such joints are called water-joints. Rebating. —The adhesion of mortar or cement, and the weight of the stones themselves, cannot always be relied upon as affording sufficient stability to stone¬ work, especially when not built into the body of the work, where they would be held in Fig. 66. Fig. 67. place by the superincumbent weight; hence different methods are resorted to in order to give additional stability, such as rebates, joggles, cramps, lead plugs , etc. A rebated or lap joint (Fig. 67) is formed by cutting away a portion of the edge of each stone, so as to RUBBLE MASONRY s. allow them to lap over each other. Fig. 68 shows the proper way of making a rebated joint on a slope, as in the case of a barge course or coping on the gable end of a building; water is thus effectually kept out, which would not be tne case if the side a were uppermost. Joggling. —Stones are said to be joggled together when prevented from sliding by a projection or he-jog- gle , on one stone, fitting into a corresponding notch, or she-joggle , in the other stone (Fig. 69). Fig. 69. The he-joggle is generally cut square, and should taper slightly from the shoulder to the end, being stronger and easier to cut and fit into place when so made. If, instead of one or more square joggles, the joggling is continued along the joint, it becomes a tongued a?id grooved joint. Fig. 70. Fig. 71. Doweling.—The above methods, except in special cases, as in Fig. 68, are wasteful both of labor and material; a better plan, therefore, is to sink, exactly opposite each other, two she-joggles or dowel holes, one in each stone, either circular or square in section, and fit into them a dowel or pin (Fig. 70), either of some 242 STONEMASONS’ GUIDE hard stone, such as greenstone, granite or slate, or brass, zinc, or copper. Copper dowels are the best, but very expensive; iron are the strongest, but should not be used unless per¬ fectly secured from air and moisture, for fear of their cracking the stone during the process of oxidizing, and as an additional precaution they should be thor¬ oughly tinned or galvanized. There is nothing, perhaps, better, on the whole, than good hard slate dowels run with brimstone or cement. Where very perfect workmanship is required, as well as when placed so as not to admit of being run in, the pins are made to fit the dowel holes accurately, being slightly tapered towards the ends, to secure a good fit and facilitate the setting of the stones. Lead Plugs.—In con¬ necting stones by means of lead, plug holes, which may be dovetailed if thought necessary, are made, one in each stone, exactly opposite each other, as in Fig. 71, with a channel leading to them from the top of the joint, through which molten lead is run into them. The bottom of the plug holes should slope downwards, so as to carry the lead into them at once, as well as to give the stone a more secure hold of the lead. Great care should be taken in running in lead that there is no moisture in the holes, whicn, if suddenly converted into steam, might cause a serious accident. Dovetail Bonding. — In masonry constructions in¬ tended to resist the shocks of waves, in addition to the methods given above, the stones may be held in posi- RUBBLE MASONRY 243 tion by being dovetailed one into the other (Fig. 72), as was done by Smeaton at the Eddystone lighthouse; but good cement and dowels would no doubt be equally efficacious, and at the same time less expensive. Tabling. —Stones of different courses may also be given great resistance to lateral shocks by tablhig (Fig. 73), in which a flat projection cut on the bed of one stone fits into a corresponding sinking in the bed of the one under or overlying it. This method, however, is wasteful both of material and labor. Fig- 73- Fig. 74 . Securing Bolts, etc., in Stonework. —Iron bars and bolts are generally secured in stonework by being enlarged or jagged at the ends—bolts so made are called rag-bolts —let into dovetailed holes in the stone, and run with lead (Fig. 74). Brimstone is often pre¬ ferred to lead, being cheaper and less liable to loosen by expansion and contraction. Protecting Cut Stonework. —Any projecting or carved stonework in a building should be boxed up with rough boarding, after it has been set, to guard against its being injured by the carelessness of workmen, or by bricks, etc., falling from the scaffolding, during the progress of the work. The treads and nosings of steps should also be boarded over for the same reason, as well as to protect them from the rough traffic. All the cut stonework should be well pointed and cleaned down before the building is given over for use. 244 STONEMASONS’ GUIDE ARCHES AND JOINTS In the first part of this work, designs for many kinds of arches were given and described, and the rules given are in many cases applicable for stonework; so I. will not burden this part with many examples, as those already exhibited, along with the few presented here¬ with, will be ample to serve the purposes of most workmen, and before proceeding further, it may not be out of place to explain a few of the terms that are made use of in connection with the construction of The face of the arch is the fronts or that portion shown in elevation. The under surface or soffit is called the intrados , and the outer surface the extrados . The voussoirs are the separate arch blocks composing the arch, the central one being the keystone. The springers are the first or bottom stones in the arch on either side, and commence with the curve of the arch. The skewbacks generally apply to segmental arches, and are the stones from which an arch springs, and upon which the first arch stones are laid. ARCHES AND JOINTS 245 The span of the arch is the extreme width between the piers or opening; and the springing line is that which connects the two points where the intrados meets the imposts on either side. The radius is the distance between the center and the curve of the arch. The highest point in the intrados is called the crown , and the height of this point above the spring¬ ing is termed the rise of the arch. The center is a point or points from which the arch is struck; and lines drawn from this center or centers to the arch are radiating joints, and are also called normals. All joints in arches should be radii of the circle, circles, or elipses forming the curve of the arch, and will therefore converge to the center or centers from which these are struck. Fig. 75 shows a segmental arch, in which the above- mentioned terms are illustrated. Fig. 76 is a semicircular arch, AB being the span and CD the rise; the left-hand half has the ordinary joints radiating from the center C , and the right-hand half, 246 STONEMASONS’ GUIDE with rebated or step joints, also radiating from the center C. This last is a sound and effective joint where great strength is required, and there is also no tend¬ ency to sliding of the voussoirs. Fig. 77 shows a semi-oval arch approaching in form that of the ellipse, and struck with three centers. This form of arch has a somewhat crippled appearance at the junction of the small and large curves, and is on that account not pleasing to the eye l It may be here observed that the true ellipse is obtained from an oblique section of the cone, and no portion of its curve is any part of a circle, and cannot, therefore, be drawn by the compasses or from centers. The method of setting out and drawing the joints requires but little explanation, AB being the span, CE the rise, and DD and F the centers, from which ARCHES AND JOINTS 247 the curve is struck, the joints converging to their re¬ spective centers. The left-hand half is shown with square bonding on face, and the right-hand half shows line of extrados. Fig. 78 is a Tudor arch, based on the curve of the hyperbola. Let AB be the span and CD the rise of arch; erect perpendicular at A , and make it equal in height to two-fifths of the rise, as at AC and CD , each into six equal parts, and draw lines from 1 to 1, 2 to 2, 3 to 3, etc., and the line drawn through the intersections of 1 these points gives the curve of one side of the arch. The other side is obtained similarly. • A thin, flexible lath is generally used for guidance in drawing an easy curve through the points of inter¬ section. To draw the arch joints: At any point in the curve, say at E , drop a perpen¬ dicular on to the springing line, as F , make BG equal BF , and from G draw line to E y which is tangent to the curve, and erect the perpendicular EH , giving the arch joint required. 248 STONEMASONS’ GUIDE The other joints are described in the same manner. Fig. 79 is another example of the Tudor arch and is a parabolic curve. Let AB be the span and CD the rise, erect a perpen¬ dicular at A and make it equal in height to half the rise, and proceed as in previous figure. To draw the arch joints: At any point in the curve, say at E, draw the chord line BD , and bisect it in F. Join FG, cutting the curve in H\ and from the point E draw line EJ parallel to EF, cutting FG in J\ on the line FG make HK equal to HJ\ join EK and draw EL perpendicular to KE, thus giving the joint line required. The other joints are described in a similar manner. Fig. 80 shows a straight or flat arch, the joints radi¬ ating to a common center. On the right-hand half the joints are not continued through to soffit or top, but have a small portion squared on, thus relieving the acute angles of arch blocks, which are otherwise liable to fracture. The springer on left hand has additional strength in having a square seating on skewback. In flat arches a camber of an eighth of an inch in a ARCHES AND JOINTS 249 foot to soffit is usually given to allow for any depres¬ sion or settlement. Fig. 81 is another example of the flat arch; the left- hand half has rebated or step joints, and the right- hand half has joggle joints. All these joints converge to a common center. Fig. 82. — In this figure a lin¬ tel with double joggle vertical joint is given. Fig. 83 shows a lintel with curved ' pig. 80. joggle joints, and is an example not often met with. The form of joint in Figs. 81, 82 and 83 is a little wasteful of material; but where stone is plentiful and in small blocks, good lintels may be obtained. Many examples of these may be seen in our modern Gothic buildings. Fig. 84 illustrates a window or door head with quad¬ rant corners; the stretching-piece or key is in one stone, with arch¬ joints resting on the skewbacks. Fig. 85 is an¬ other form of head, the square Fig. 81. seating in each stone giving addi¬ tional strength, and the joints converge to common centers. Fig. 86 shows cb.ree joints used in landings. A is a joggle joint, commonly called he and she- 250 STONEMASONS’ GUIDE joggle. A tongue is cut slightly tapering on one edge, fitting into a corresponding groove worked in the other edge. Run in with cement, it forms a strong and secure joint. B is a rebated joint; this is sometimes undercut. C is a bird’s-mouth joint. Grooves are roughly cut in on the edges of these joints opposite each other, and the cavities run with cement grout. Slate dow¬ els are also laid longitudinally in the joint and run with cement. ME 1 Fig. 82. Fig 87 is a horizontal lintel or architrave spanning an opening, with an apparent vertical joint, but con¬ cealing a secret arch joint. This is used chiefly in colonnades, porticoes, etc., where stones of a suffi¬ cient length are not attainable, and sometimes also for convenience of hoisting and fixing. An indent is formed the shape of the reverse of a wedge in joint of abutment, and a wedge-shaped pro¬ jection is cut in key¬ stone, fitting neatly into the indent. This makes a good and secure joint „ without doweling or Fig. 83. . s cramping. Fig. 88 shows sketch of weather or saddle joint in cornice. This joint is made by leaving at each end of the stone a ridge or roll, the formation of which is generally left till after fixing. This roll effectually prevents the water running through the joint. The ARCHES AND JOINTS 251 roll is not usually seen from the front, as the nose of cornice is continued straight through the joint, although it is also in some cases made a feature of. This joint is used chiefly for cornices and window sills where there is a large projection. Fig. 89 exhibits a rebated joint in gable coping. This joint is serviceable, inas¬ much as it keeps the water out of the joint and the wall dry, although it is somewhat expensive. Fig. 90 is an example of various bed joints in stone spires, being respectively: A. A horizontal bed joint. B. A bed joint at right angles to batter C. A rebated or stepped bed joint. D. A joggle or tabled joint. Fig. 85. The bed joints of the stones are usually cut at right angles to the batter or face of the spire, as at B; but horizontal beds, as at A, are supposed not to involve so much thrust at the base. But for obviating any 252 STONEMASONS’ GUIDE outward tendency, a chain or rod-bond, united at the angles and inserted in a cavity at the base of the spire, is sometimes used. The two bed joints C and D are both a little wasteful of material, but for stability and strength these are by far the best form of joints. A word may be said as to the thickness of the work; this will depend chiefly on the height of the spire and the quality of the stone. From ten or twelve inches at « the base, diminishing to six inches or even less at the top, may be generally considered sufficient. The stonework of the spire of Salisbury Cathedral (the spire, reckoning from the tower, being 204 feet in height) is two feet thick at the base, and gradually ARCHES AND JOINTS 253 diminishes in thickness to about twenty feet above the tower, where it is reduced to nine inches, and is con¬ tinued at that thickness to the capstone at the summit. Fig. 91 shows ashlar in courses with joggle joints. This is a very unusual form of joint, and is used, no doubt, more for effect than utility. There is a waste of material and labor, and a better result maybe obtained by the use of slate cramps. However, there are some examples of it in modern buildings. Fig. 92 is a seating to sill, with a slate or copper dowel to prevent lateral motion. Mortises are cut opposite to each other in the two beds, and the dowel made secure by being run in with cement. The dowel is a most useful adjunct in good and secure fixing. Fig. 93, A, is a metal cramp for securing joints together. A chase or groove is cut in the stone of a sufficient width and depth, and at each end a mor¬ tise hole is cut to the exact size of inside of cramp, so that it fits tightly and requires to be tapped into its place; it is then run with melted brimstone or cement. 254 STONEMASONS’ GUIDE The use of iron cramps and dowels in connection with stone is generally attended with some danger, on account of the iron rusting, which causes an increase in size, and subsequent fractures and discoloration of the stone. But if the iron is properly protected by galvanizing or japanning, the risk is reduced to a minimum. The best metals for cramps, dowels, etc., are copper, gun metal, or brass, but these are expensive and are therefore not much used. B is an example of a slate cramp also used for connect¬ ing joints together, and is an excellent and economical substitute for metal. It is made dovetail in shape, let in flush to the bed of the stone, and then run in with cement. Fig. 94 shows a plugged or lead doweled joint. This is chiefly used in copings, curbs, strings, arches, etc., and prevents the joint work¬ ing loose or “drawing.” Two holes, dovetail in shape, are sunk in the joints opposite each other and a small groove is cut from the top to each hole and run in with cement. Slate dowels are sometimes used for this purpose, and run in with cement. Fig. go. ARCHES AND JOINTS 255 Fig. 95 shows a lewis, or holding-down bolt, let in a dovetail hole and run in with lead. The openings in stone of small span arches are generally bridged by stone lintels in one piece, or lintels built on an arched construction if a number of stones are used. If lintels of one piece are employed in walls other than ashlar, a rough arch is generally built above to relieve the lintel of the weight of the superincumbent wall, as shown in Figs.-96 to 98. A second method of relieving the lintel, commonly adopted in sneckea rubble work, is to construct a flat arch of three stones above the lintel, as shown in Figs. 99 to 101; the center stone or key is termed the save. In bedding the save stones no mortar is placed on the 256 STONEMASONS’ GUIDE lintel, but the stones are supported in their position by means of small wood wedges. After a sufficient mass of the wall has been built to tail down the side saves, the wedges are removed. In finishing the wall, the joint between the saves and the lintel is pointed only; thus no weight from the wall above is brought to bear on the lintel. A large number of stone openings are formed with flat heads, and where stones of sufficient dimensions cannot conveniently be obtained in one piece, some form of flat arch is adopted. Fig. 94- Fig. 95. Figs. 102 to 105 show a flat arch, with secret jog¬ gles. These latter are worked out of the solid stone, the key having two joggles; the springer is recessed only, and is made sufficiently long to tail well into the wall, the remaining voussoirs being joggled on one bed-joint and recessed on the other; the cornice over window in this example is supported by a console or bracket. Figs. 106 to 108 show the construction as a flat arch, the bed-joints stepped to prevent any voussoir sliding on its bed-joint. This method is largely used for terra-cotta work. This example illustrates an archi¬ trave about window, supported at sides by a half col¬ umn with cushion frieze and segmental pediment above. The internal jambs are splayed, and illustrate Fig. ioi. Fig. 99. Fig. 97. Fig. 96. ARCHES AND JOINTS 2*7 Fig. 100 Fig. 98. 258 STONEMASONS’ GUIDE ARCHES AND JOINTS 2 59 /-O' /O' I Qc/ar~/e/~ Co/umn. J orfee/^ Fig. 107. S)cj/e kiiFrtntH^ Fig. 106. Fig. 108 i ± 260 STONEMASONS’ GUIDE E/c vat/on Check or RebsiTe /br choof j of feet" Sc*/e%^ Figs. 109 and 110. Fig. 116. Fig 114. Fig. 113. Fig. in. ARCHES AND JOINTS 261 Fie. ik. Fie. 112 262 STONEMASONS’ GUIDE ARCHES AND JOINTS 263 264 STONEMASONS’ GUIDE Fig. 123. Fig. 124. Fig. 125. Fig. 126. the use of sconcheons. A coke breeze lintel case in situ is shown over the internal opening. Figs. 109 and no illustrate a semicircular opening in an ashlar wall, the blocks of which have chamfered joints. In these arches it is necessary to extend the bed joints of the voussoirs till they intersect the courses of the work; this results in the voussoirs gradually getting longer as they approach the key. Another method of arranging voussoirs is shown on right hand of Fig. 109. In this the bed joints of the voussoirs are extended to meet the horizontal courses, and are then returned a con¬ venient distance along the horizontal course; this prevents the vertical joints of the voussoirs coming too close together near the springing. ARCHES AND JOINTS 265 Tigs, hi to 113 show a rectangular opening, spanned by an arch,- the dressings and voussoirs of which project beyond the wall face about 1 inches, have chamfered joints, and are vermiculated on surface to give importance to the opening; this form of opening is commonly adopted in the basement stories of clas¬ sical buildings. Figs. 114 to 116 show a similar opening, the voussoirs projecting as they approach the key and the joints of the masonry being rebated. This is also used for casement stories of classical buildings. Stone being a granular material, anything approach¬ ing an acute angle is liable to weather badly; therefore in any tracery work, having several bars intersecting, a stone must be arranged to contain the intersections and a short length of each bar, as shown in Fig. 117, and the joints should be (a) at right angles to the directions of the abutting bars if straight, or ( b ) in the direction of a normal to any adjacent curved bar. This not only prevents any acute angles occurring, as would be the case if the joints were made along the line of intersection of the moulding, but also ensures a better finish, as the intersection line can be carved more neatly with the chisel, and is more lasting than would be the case if a mortar joint occurred along the above line. In no case, either in tracery, string courses, or other moulding, should a joint occur at any miter line (Fig. 118). Figs. 119 to 122 illustrate the jointing and building up of a pointed arch with plate tracery and a rere-arch. Figs. 123 to 126, illustrate a pointed arch in three orders, with inner opening raised to allow door to open. Tracery.—Wherever the moulded members of the 266 STONEMASONS’ GUIDE tracery admit of it, the practice should be followed of designing the tracery and fitting in rebated stone reveals, similar to the method of fixing wood frames in reveals, as it is found to be easier to fix the tracery after the opening is built. STONE STAIRS AND STEPS These consist of a number of blocks, fixed at regular and convenient heights, to facilitate transit between planes of different levels, and are of three kinds: (i) those stairs supported at both extremities; (2) those fixed at one end, (the other end being left free), and known as hanging steps; (3) steps circular in plan. These latter are divided into two classes: (1) those with a central newel; (2) those with an open well. The steps may be in one of two forms, either rectan¬ gular or spandrel, as shown in Fig. 127. In the com¬ moner stairs the rectangular blocks are used, but where a good appearance is desired or to gain head-room, spandrel steps are employed. The spandrel steps may be finished in one of three ways: (1) with a plain soffit, which consists in finishing the soffit in one plain sur¬ face, as shown in Fig. 127; (2) a broken soffit may be employed, as shown in Fig. 127; this is used for one of three reasons, or for all combined: (a) to gain strength at the back of the tread; (b) to save the expense incurred in working the surface of each step perfectly level; ( c ) to obtain effect; (3) having the soffit moulded. Each step may simply rest upon the one below it, but it is usual for the upper step to be rebated over the back of the one below to prevent sliding. To avoid acute angles at this point, and to form an abut- STONE STAIRS AND STEPS 267 ting surface, particularly in the spandrel steps, a chamfer is taken off the top back edge of the lower step at right angles to the pitch of the stairs, the upper step having a corresponding sinking to fit. This is known as a back joint, and is shown in Fig. 127. Fixing the Steps. —Stone stairs are erected in one of two ways: (1) they may be built in the walls as the latter are built, or (2) spaces may be left in the walls to receive the ends of the steps, which are fitted and fixed when the wall is finished. The wall should be built in cement mortar for at least 12 inches above and below the line of the stairs, the gaps to receive the stairs being temporarily filled up by brickwork bedded in sand. The ends of the steps should be pinned in the walls with tiles or slates set in cement, care being taken that the space left about the end of the step is filled up, as 268 STONEMASONS’ GUIDE far as possible, with solid material, leaving no thick mortar joints to squeeze out. While the steps are set¬ ting, the outer or free end should be supported with wood struts, after being leveled, which should remain until the cement has thoroughly set. The first kind of stair, viz., those supported at both ends, combine convenience with the greatest strength. They are much used in schools, theaters, and other public buildings. They are usually made of rectan¬ gular steps, which rest six inches on the wall at either extremity. STONE STAIRS AND STEPS 269 The second kind, or hanging steps, are much superior in appearance to those last described. They derive their chief support from the walls, but each step receives an additional amount from the one directly beneath it. These are used for all conditions of stairs, from the secondary staircases in dwelling-houses to the grand staircases in public buildings. In the com¬ moner kinds, rectangular steps are used; but in the superior, spandrel steps are always employed. The steps may be plain or have moulded nosings; where the latter are employed, the moulding should be returned about the free end, the moulding on the latter being returned and stopped directly beneath the riser of the steps above, as shown in Fig. 127. When the staircases are very wide, it is advisable to support the steps at their outer ends by steel joists or cantilevers at intervals, the strength of stone under cross stress not being very great. Fig. 127 shows a landing supported by a joist. The first of the third class of stair, the circular newel, is used for turret steps; they are built in a circular chamber. The steps are wedge-shaped, their thin end being worked circular to a radius of about 3 inches, the front edge of each step being tangent to this circle, the back edge of the step being a radial line. The steps are built into the walls of the cham¬ ber, at their wide ends, each of the circular ends being arranged to fall directly over the one beneath it, thus forming a continuous newel up the center. These form a strong stair, but are rather dangerous, as they have to be steeply pitched to gain the necessary head-room. Secondly, those formed with an open well are built in the same manner as the hanging stair, of which they form one variety. Stairs, circular and elliptical in 2J0 STONEMASONS’ GUIDE plan, are often built between two walls, as in the first class of stair. Large stone landings which cannot be obtained out of one piece of stone are joggled at their joints, and where the slabs are thin and are likely to be subjected to heavy traffic, should be supported by steel girders. The balusters in stone staircases are always of iron, which is better for fixing purposes. There are two methods of fixing balusters: (i) fixing them into the top, suitable for standard balusters, as shown in Fig. 127; (2) fixing them into the side, when they are termed bracket balusters, as shown in Fig 127. Holes are bored in the steps at the proper intervals, being slightly undercut. The ends of the balusters are indented before being inserted; they may be fixed in with lead, Portland cement, sulphur, and sand, or asphalt, as previously described. Figs. 127 and 128 show plan, elevation, and details for an open well hanging stair, built of good hard stone. The lower flight shows handrail supported by standard balusters, the upper portion with bracket balusters to obtain the maximum quantity of available stair space. The method of setting out a scroll and curtail step is shown. Stone Roof.—Fig. 129 shows the method of forming a stone-covered roof over a vaulted chamber, such as was frequently used during medieval times in military and monumental buildings. It is formed of stone flags bedded on rubble filling over the vault. In these roofs the flags are laid in two systems, the lower and the upper; in the first the flags are spaced apart, in the second the flags are bedded with a lap of 2 or 3 inches over the top edges of the flags in the first system. The whole upper surface has a slight fall for drainage. Fig. 129. Co/ttng yJo/Vrts. 2J2 STONEMASONS’ GUIDE Mouldings. —Mouldings may be classified under two heads, Classic and Gothic. The Classic are those derived from those employed by the Greeks and the Romans Invariably the Roman mouldings are found to have their prototype in the Grecian examples, the chief difference being that the Greek are either seg¬ ments of some of the conic curves or are struck free¬ hand, while the Roman curves are all segments of circles (Figs. 130 to 138). ' There are nine typical examples, as follows: /. Fillet .—This is a narrow, flat projection, often used to divide individual mouldings or groups of mouldings in any composition; it is similar in both Greek and Roman work, as shown in Fig. 134. 2. Astragali a small semicircular moulding, as shown, often used in combinations of mouldings, but chiefly to mark the division between the shafts and caps of col¬ umns. This member is similar in Greek and Roman. j. Cavetto .—The cavetto is a hollow moulding, con¬ sisting in the Greek of a quarter of an ellipse and in the Roman of a quadrant. 4. Ovolo .—This moulding in the Greek consists of a segment of an inclined ellipse, having a fillet at the top and bottom, and forming at the top a quirk. In Roman work it is a quarter circle, bounded at top and bottom by a fillet. 5. Cyma Recta .—This is a double curve, formed in the Greek of two quarter ellipses whose minor axes are in the same straight line and bounded top and bottom by a fillet. The Roman example is similar, but consist¬ ing of two quarter circles. This moulding has a con¬ cave portion of its surface above the convex, and is generally used as a crowning member. 6 . Cyma Reversa, as its name implies, is the reverse of STONE STAIRS AND STEPS 273 Crowning Moulding's Supporting Moulding's'' Cyma oRecta Cavetto Cyma Re vers a Ovo/o Connect in Moulding* Fillet Band or Listel Astragal Scotia Base Mould mgs Torus Bird's Beak. Figs. 130 to 138. the preceding moulding, slightly modified in the Greek by having a quirk above, between the same and the fillet, and the hol¬ low portion slightly more concave. The Roman is an exact reverse. j. Scotia .—The scotia in the case of the Greek is formed of an inclined ellipse, having a fillet above and below. The Roman is struck from two centers on a common radial line. 8 . Torus .—The torus is a base moulding, the Greek form being Ihe reverse of the scotia. Many Greek examples are, however, similar to the Roman, consisting simply of a large semicircle with a quirk below and fillet above. q. Bird's Beak. — This moulding only occurs in the Greek mouldings; it consists of a quarter ellipse, with the major axis horizontal, in the lower side of which a small hollow has 274 STONEMASONS’ GUIDE 'Rolf and |/ 5 /a/r> L R oll Reel Shallow HoHo>^\ BowfeU ^ Bow fell and Billet Moulding Scroll jm^Ro!/and J \ Moulding r ^ Triple Fillet basement Double Ogee. Filleted * Roll Wave Moulding Sunk I Hollow Chamfer I Chamfer String and 1 Labe/ Mow/c/mgs g ^<5 s Column Bases Wo//wlBases. Capitals Types of Gothic Mouldings. Figs. 139 to 165. STONE STAIRS AND STEPS 275 been worked, and is used as a supporting moulding. In the designing of groups of mouldings for cornices, strings, etc., reference should be made to the suit¬ ability of the forms for their intended position, and for this purpose they may be divided into base mould¬ ings, connecting mouldings, supporting mouldings, and crowning mouldings. The base mouldings would include such mouldings as the torus, the scotia or the inverted cyma recta, and any combination of such mouldings that would tend to broaden the base and distribute the weight of the mass supported. Connecting .—These include the fillet and the astragal. Supporting .—The supporting mouldings include such members as the ovolo, bird’s beak and the cyma reversa, mouldings that do not have their hollow members near their upper edge, and such as have their mass in a posi¬ tion to strengthen them, and are fitted to act as cor¬ bels. These mouldings are used to form the bed mouldings or lower parts of combinations, such as cornices which are divided into two parts, the bed mouldings and the crowning mouldings. Crowning Mouldings are those mouldings which are not expected to carry anything above, such as the cyma recta and the cavetto, the top members of which are small and delicate. The above ideas are not always rigidly adhered to, and successful departure from them is often made with good effect; but it is prudent to bear these principles in mind when designing any groups, for if too widely departed from, confusion ensues. Gothic Mouldings. —Figs. 139 to 165 give a selection of the mouldings commonly used in the Gothic periods, combinations in archivolts, also for strings, wall bases, bases and capitals of columns. SPECIFICATION CLAUSES MATERIALS STONE 1. The whole of the stone to be of the best description of its respective kind, and to be free from sand holes, vents, flaws, and all other defects. Should it be disapproved it shall be removed at once from the site. • 2. Any stone which will not sustain a load under test of 2-in. cubes equal to.lb. per sq. in. may be rejected and the contractor is to furnish to the architect, if demanded, fair cut cubes taken from any stone challenged by the architect, and the test of such cubes shall be considered a test for all the stone of a similar character. 3. The.stone is to be obtained from the quarry of. to be equal in all respects to sample blocks deposited with the architect, and approved by him in writing. Note. —This clause should be repeated for each different stone to be employed in the building, to prevent the substitution of an inferior material. In no case should an architect specify partic¬ ular stone by a general trade name. In the case of sandstone for sills, hearths, etc., the following clause may be used. 4. The stone is to be of an approved quarry, and the contractor is to deposit samples of the stone he proposes using with the architect, and obtain his approval in writing before ordering same. 5. All cut stone work of every description, including window and door sills, caps, corbels, cornices, steps, railings, brackets, balcony floors, chimney caps, copings, fireplace lintels to be cut as per plans, details, etc., for the same, and to be delivered at the building properly fitted and with all necessary lewising and drill¬ ing for anchors by the stonecutter. 6. Any stone found at completion to be broken or defective is to be cut out and replaced by the contractor. 276 SPECIFICATION CLAUSES 277 MATERIALS FOR OTHER TRADES FOR “DRAINLAYER” (HOUSE DRAINAGE) 7. Provide good stone covers for air inlet chambers, 2 ft. 9 in. by 2 ft. 9 in. by 4 in. thick, finely tooled on top and edges, with rebated perforation for cast-iron hinged grating in frame. 8. Provide good stone covers 3 ft. by 3 ft. by 4 in. thick, for partially covering manholes, as shown on drawings, with circular perforation, 1 ft. 9 in. in diameter, for entrance. 9. Provide stone covers, 2 ft. by 2 ft. by 4 in. thick, for tops of lamphole shaft, terminating in roads or carriageways, with per¬ foration the full diameter of the top of the pipe. The covers to be finely tooled on the top and edges, and to have 3 in. block letters “L. H.” cut in on the surface. 10. Provide for inspection junctions stone covers, 18 in. by 18 in. by 3 in. thick, finely tooled on top and four edges to have 3-in. block letters “I. J.” cut in on the surface. 11. Provide for the cleaning eyes stone covers, 18 in. by 18 in. by 3 in. thick, finely tooled on the top and four edges, to have 3-in. block letters “C. E.” cut in on the surface. FOR “MECHANICAL ENGINEER” 12. The cover for engine bed to be of.stone, 16 in. thick, with chamfered edges, holed through in four places for hold¬ ing down bolts, all as shown on drawings. 13. The coping for walls of flywheel race to be 9 in. by 6 in. .stone boasted coping. 14. The flag cover for boiler sides and flues to be 3-in. hard .stone flags with boasted overhanging edge. 15. The coping for blow-off pit to be 9 in. by 6 in. stone boasted coping rebated for iron plates. WORKMANSHIP—GENERAL WORK 16. All stone work to be set in best manner, every stone well bedded with complete full squeezed out joints in cement mortar, and all work in contact with brick to be plastered with similar cement to protect from stains, and all the brick backing of same to be set in similar cement mortar. 17. All stones to be well wetted before setting, and large stones to be set with a derrick Rake out mortar joints when setting. 278 STONEMASONS’ GUIDE 18. The joints between cut stone blocks in all columns or where- ever any weight is brought on any cut stone work to be made with 5-lb. sheet lead worked back from the face 2 in., the center being cut out to allow space for settlement. 19. No angle miters will be allowed in any part of the work. 20. All window sills and all belts forming window sills to be in one stone each if desired by the architect. 21. The lines of all mouldings, curves, angles or miters to be worked to their true and proper forms, and all returns of miters of mouldings, washes or bevels to be worked on and out of the solid. The beds and joints of all stonework to be square with the face. 22. All rebates for frames to be cut in the stone joints accord¬ ing to plans and directions of the architects. All the windows or other finish of stone to be in size and form as shown on detail drawings, moulded, etc., according to the details of each part. 23. All stonework to be jointed as shown or directed. 24. Fix in all joints, where shown on details or as directed, copper dowels (provided by “coppersmith”), tailing equally into each stone, and run with oil cement. No iron dowels, galvanized or otherwise, will be allowed, and if brought on the job shall be returned immediately. 25. Carefully perform all cuttings and dowelings of holes for iron railings, crestings, bars, anchors, etc. Also all cutting for all galvanized iron, tin and lead flashing to the several roofs and wherever else required. 26. Chases to be left in all walls where shown on drawings, or wherever required for the running of steam, gas, and water pipes, or for any other purposes which may be found to be necessary after the work has been built. Cut chases and break out holes for steam, water and gas pipes, or for any other purpose. 27. The front entrance to have ..in. by ..in.stone rubbed top and front, and back-jointed step with sunk and moulded front, and with short returned sunk and moulded ends. The tradesmen’s entrance to have .. in. by . . in. good free stone, tooled top and front, and back-jointed step. All steps to be kept up 2 in. above floor to allow for thickness of mat. The doorways to...to have. .in. sound, free stone, SPECIFICATION CLAUSES 279 rubbed, and back-jointed both edges, thresholds the full widths of the walls. All steps and thresholds to have mortises for dowels of door frames. 28. To be of.stone 14 in. by 6 in., wrought, sunk, weathered, throated, and rubbed on all exposed parts, including the soffit of the projection, grooved for metal tongues, and set in mortar. All to have proper stools for jambs. 29. Finish the parapet next.with 14 in. by 6 in. suitable stone rubbed saddle-backed, double-moulded (to detail), and double-throated coping, with kneelers, springers, bonders, etc., of the sizes shown. Finish the parapet over.with 13 in. by 3 in. suit¬ able stone, tooled and weathered coping throated on both edges. All copings to have lead-plugged joints. Note. —Iron should not in any case be used as cramps. Should cramps be preferred to lead plugs, copper or gun metal should be used. 30. Carefully bed and dowel all cornices in cement mortar. 31. The heads to windows where shown to be stone to be of .stone stop, moulded to detail of the sizes shown, and 6 in. longer each end than the width of the opening. 32. The staircase from ground floor to basement to have. . in. by ..in. tooled all round threads, and ..in. by ..in. tooled all round risers. The staircase from ground floor to.to have . .in. by ..in. rubbed all round.stone spandril steps, splay rebated and splay back jointed with sunk and moulded fronts with solid square wall ends. The other ends to be returned and moulded to match fronts. The bottom step to be solid with curtailed end as of the size shown. The landings to be. .in. thick, sunk and moulded on free edges to match steps with cement-plugged joints. Fill in between landing and steps below same with ..in. by ..in. splay rebate and splay back-jointed filling-in piece with fine rubbed joint. All ends of steps and edges of landings next walls to be built in at least 4£ in. 33. Properly cut and pin, or build in the walls, all ends of steps, edges of landings, etc., requiring it. 280 STONEMASONS’ GUIDE 34. Put 4 in. rough.stone corbels under all over¬ hanging chimney breasts. 35. Turn relieving arches of such span as may be directed in walls over weak spots in the foundations or over openings. 36. Put under ends of rolled joists up to . .in. by . .in., 14 in. by 9 in. by 3 in., under ends of larger rolled joists 14 in. by 14 in. by 4 in., and under ends of riveted girders 18 in. by 14 in. by 6 in. .stone templates, finely tooled for iron, and with tooled edges where exposed. 37. The columns and stanchions to have 21 in. by 21 in. by 6 in. .stone bases finely tooled for iron and mortised for lugs. Note. —The columns and stanchions to be slightly wedged up with steel wedges, and run in with neat cement. 38. Chimney stacks to be worked according to detail drawings and properly cramped as directed. The top stone of chimneys where possible to be in one stone with holes cut through for flues. 39. All rolled joists and girders carrying walls to have 3 in. stone tooled covers with coped edges bedded in cement. All riveted girders to have bed of cement on top of same to cover rivet heads. 40. Put 3 in. rough stone flags bedded and jointed in cement as cover to dry area. 41. The curb to area outside.to be 9 in. by 6 in. .stone tooled all round with cement-plugged joints. The curb to area outside.to be similar, but rebated for pavement lights. 42. The kitchen and scullery fireplaces to' have 2£-in. stone rubbed front and back hearths. The remaining fireplaces where stone hearths are shown to have 2 in.stone rubbed front and back hearths. All to be 12 in. longer than the width of opening and 18 in. projection, except to kitchen, which is to be 24 in. projection. 43. The kitchen chimneypiece to have 7J in by 2 in. stone rubbed jambs, and 9 in. by 2 in.stone mantel and shelf. The shelf to project 6 in.each end beyond mantel, with rounded corners, and to be supported on 12 in. by 6 in. by 2 in. rubbed and moulded stone corbels cut and pinned in wall. 44. Provide and fix.stone rubbed and dished sink in SPECIFICATION CLAUSES 281 scullery 3 ft. by 1 ft. 8 in. by 5 in., all in clear, the bottom to fall and holed for grating. Note. —Glazed stoneware sinks are generally preferable to stone, except in special cases. 45. Provide and fix as shown a 4 in. chamfered and holed top to copper, to be in one slab of rubbed.stone. 46. Cut all grooves and rebates as may be required for glazing, etc., up the jambs and mullions, and in the tracery, and well point upon both sides with coarse putty. 47. Form rebates for iron casement frames, and provide plugs and holes in stone to each. 48. Mortise steps, sills, etc., for tenons of door frame shoes, and run in the tenons with lead. 49. Each bell pull at entrances to be let into a stone 9 in. by 9 in. by 9 in., set in cement and sand, sunk for pull, and mortised for wire. 50. Cut proper mortises in the stone for the ends of all saddle bars, stanchions, etc., and run in with cement; properly let in and run with lead all double fangs o c hinges, staples, catches, sockets, etc., as may be required. 51. All works intended for carving to be prepared by the mason, and all boasting necessary to be done by him, great care being taken to leave sufficient stuff to give the carver plenty of scope. The carving to be done by professional carvers approved of by the architects, and according to detail drawings to be furnished. Carving to be done either on the ground or in position after the building is up, as directed by the architects. 52. Provide and allow for selecting a specially jointed founda¬ tion stone and for cutting inscription on same of about. letters 2 in. high, and cutting a cavity in same, and provide an air-tight solid copper box to hold papers, etc., to be deposited in same, and allow for extra labor and materials in setting stone with usual ceremonies. Also provide and allow for clearing up the parts of the building near the stone on the day appointed by the building owner, and making the premises clear and safe and available for the usual assembly and allow for interruption of such work as necessary. 53. Thoroughly clean down all work at completion and clean out and point all joints in cement, tinted to match stone, well tucked into joints and finish with a neat flat surface. 54. Lime whiten all exterior wall surfaces, mouldings, etc. 282 STONEMASONS’ GUIDE SPECIAL CLAUSES FOR A CHURCH LABORERS 55. The whole of the stone to be of the best description of its respective kind, to the architect’s approval; to be free from sand holes, vents and all other defects; to be worked to lie on its natural bed when set, and to be bedded and jointed, except where otherwise described, in mortar (or putty), with wide (or fine) joints, which are intended to show. All the stone is to be worked on the site, and particular care is to be taken to preserve all the joints of the stonework from the irregular appearance which is caused by the arrises being broken before the stones are set. No work thus injured will be allowed to be used, and no patching will be allowed. The stonework to be so truly worked as not to require any cleaning off beyond washing. 56. All the dressings (unless otherwise described) to be finished off with a fine drag (or a chiselled face or rubbed) in a manner to be approved by the architect, and to be bonded and fixed in the most substantial manner. 57. The vertical joints of sills, parapets, cornices, and all joints in tracery of windows, in vaulting ribs and chimney caps, are to have double cement plugs and mortises for same, or double V- grooved joints run with cement as may be necessary. 58. The mullions, copings, jamb shafts, pinnacles, and such are to have 1 in. or lj; in cube slate dowels (as required) to every stone in the bed, run with cement, with proper mortises for the same DRESSINGS 59. The external dressings of windows and doorways, also the copings, strings, gable crosses, weather courses, weatherings, etc., etc., are to be executed in. All external angles of dressed stonework to be worked in the solid. 60. Provide and fix hinge and lock stones as shown on the drawings and as required. (It is sometimes advisable to make these stones of a harder material than the dressings.) 61. The internal dressings, unless otherwise described, are to be of., finished with finely-rubbed faces. 62. All internal angles of dressed stonework to be worked in the solid. 63. The detached piers and springers over same are to be exe- SPECIFICATION CLAUSES 283 cuted in.stone. Internal detached shafts to be of .stone (or marble, etc., etc.) as required, the whole to have circular, finely-dragged faces, or to be chiseled (or rubbed), the top and bottom beds to have mortises run with cement, and the intermediate joints to have light copper cramps as may be directed. ASHLAR 64. The internal facing throughout to be of.stone ash¬ lar. The external facing is to be of.stone, ashlar. The courses are to be of various heights (averaging 6 in. on the bed) from 4 in. to 10 in., and to line generally with the beds of dressed stonework. They must also be properly bedded and bonded into the body of the walls. Each stone must be set in mortar, cut, and properly fitted up to the dressings, arches, etc., and be fin¬ ished with a finely-dragged or chiseled face. VAULTING 65. The springers of the vaulting must be worked on the solid as shown on detail drawings; they and the wall ribs are to be built into the walls as the work proceeds, but those portions of the groin ribs which are fully developed on the springers, as well as all the filling in, will have to be set after the roof is up and covered in. The contractor is to allow for any extra scaffolding, labor, etc., that may consequently be required. 66. The cells of vaulting are to be filled in with.stone 4 in. thick in narrow courses built in mortar, the soffits to be slightly arched or cambered,- and the surface to be finely dragged or chiseled to match the internal ashlaring, etc.; it is to be cleaned off and the joints struck as the work proceeds, to be pro¬ perly cut up to the stone ribs, and to have all necessary centering or laths that may be required for the support of the cells whilst building. SUNDRIES 67. The gable crosses to be of.stone worked according to the drawings, and fixed with 3 in. by 1 in. by 1 in. slate dowels run with cement. 68. The masonry in all towers to be built with special care with large flat stones, carefully bedded, each stone to break joint over the center of the stone below. Not more than.stones to be placed in the width of the wall set in mortar and grouted as described for the other portions of the work. All joints to be 284 STONEMASONS’ GUIDE true and close, filling in the walls with spalls will not be allowed. 69. The tops of the turret and chimney stack are to be built as shown on the drawings, the top and cap stones of turrets and the top stone of chimney to be solid and perforated for the flues and finial rods as required. 70. A weather course to be fixed round chimney stack, also on ., all with solid springers, apex, and bond stones about 4 ft. apart. (Some prefer to work these entirely on the solid.) 71. The chimney-piece in vestry to be formed in. stone, as shown by the detail drawing, and to be properly dow¬ eled together and tied with copper cramps into the walls. The fender to be of stone, 3J by 3J in., rubbed and moulded, with dowels and cement plugs as required, and to have circular comers as shown by the drawings. 72. The seats in sedilia, the bottom of piscina, etc., to be also of.stone, all of the widths and thicknesses shown, FLOORS AND STEPS 73. The altar stone to be a 6 in. rubbed.slab in one stone, and of the size of the altar as shown. 74. The steps within the chancel and at the entrances thereto are to be of the best selected.stone, rubbed top and front and back-jointed; to be in long lengths with fine joints and double cement plugs in same, and of the sizes shown; all to be bedded hollow on brickwork. Similar steps to be fixed. 75. The heating vault and.to have 2\ in. tooled. paving in mortar. CARVING 76. Provide models to the approbation of the architect, made by an artist, for the whole of the carving; the whole to be made to a scale of 3 in. to 1 ft. 77. Perform in an artistic manner to the satisfaction of the architect, the carving of the pendants, battlements, foliated arches, finials, crests, small domes, and of every other part of the building. Note.— It is more often the custom in the best work to insert a provision for the carving of a building, such sum to include cost of making necessary models. 78. Clean down the masonry work and generally leave the SPECIFICATION CLAUSES .285 Whole perfect and complete, omitting no material or workman¬ ship either described or implied by the drawings and this specifi¬ cation, or that is necessary to render the whole complete in every respect. Note. —Many architects will not allow any cleaning down. There is little doubt but that the custom is injurious to some stones, as it removes the natural case-hardened weather-face. SPECIAL CLAUSES FOR A BUILDING IN A STONE DIS¬ TRICT 79. The stone for wallings, footings, and dressings generally to be obtained from.quarry. (If the quarry belongs to the building owner, insert the following:—No royalty will be charged, but the contractor will have to quarry the stone and convey it to the building. The quarry to be left in good order at completion.) Stone for sills, mullions, transoms, string courses, cornices, copings, weatherings, and other exposed positions to be obtained from the.quarry belonging to Mr. The whole of the stone to be set so as to lie on its natural quarry bed. 80. Build the footings with large flat-bedded rubble walling stones, specially selected for the purpose, in mortar thoroughly bonded, bedded perfectly level, filled in solidly, and flushed up with mortar. Properly lay up the cellar walls with good hard flat build¬ ing stone.in. thick, firm built and well bonded with a' thorough stone at least in every yard super., laid in clean lime and cement mortar in parts of one of cement and two of lime, laid by and full to a line on both faces and flush and point at completion. Lay down in like manner substantial foundations under all chimneys, piers, and exterior steps, and all clear of frost. Leave all openings in walls for drain, gas and water pipes, as directed or as shown on plans. 81. The walls to be carried up in roughly-chiseled ashlar in mortar, to be thoroughly bonded and packed, and well flushed up with mortar and small stones. 82. The inside face to be carried up true and even in brick¬ work to receive plaster (4£ in. lining properly bonded with head¬ ers into wall). 83. The outside surface to be executed in roughly-chiseled 286 STONEMASONS’ GUIDE ashlar (the local rubble stone in horizontal random courses to average 7 in. on bed with one bond stone at least to every yd. super., the beds to be roughly hammer dressed, and the surface to be chopped to remove any great irregularity as shall be directed, the courses to vary from (3 in.) to (7 in.) high, and in stones between (14 in.) and (24 in.) long with occasional large square stone). The pointing to be done as the work is carried up by passing the point of the trowel over the joint, so that the mortar shall in no case project over any portion of the stones, and the joints to be slightly weathered. 84. The quoins to be got out of the best local weather stone, to be long each way on the bed, and well bonded into rubble walling, the angles to be truly formed, and the surface to be axed with irregular upright and diagonal strokes as shall be approved, or, if of rubble, “the quoins to be executed in selected large stones.” 85. Provide for covering the tops of walls with asphalted felt if they should be micovered during frost or very wet weather. APPENDIX In order to make this book as useful as possible I have thought it proper to add this Appendix to it, which, in my opinion, offers the best and most simple solutions to the problems discussed in this department It is taken from the works of Wm. R. Purchase, one of the best known authorities on Cut Stone Ma¬ sonry. The subjects dealt with are of the most difficult kind known to the art of masonry, but here they are reduced to the simplest manner possible, and the rules are made so plain that any ordinary workman should be able to thoroughly under¬ stand them. ARCHES CIRCULAR ON PLAN, OR ARCHES OF DOUBLE CURVATURE To describe the construction of a Semi-circular Arch in a Cylindrical Wall, the development of which on convex or outside face is a semi-circle, and on concave or inside face is a semi-ellipse, the soffit radiating to a center at springing, and the crown of the arch level or at right angles to the vertical face of the wall. Fig. 1.—Shows plan of the arch, BCD being the opening, the arch radiating to O, the center of the cylinder. To set up the Elevation on the Development for the Face Moulds. Fig. 2.—Develop the segment A B C of convex face (Fig. 1), setting out the length on springing line as A B C from C as the center; erect a perpendicular as center line, and describe with C B as radius half of the semi-circle. Set off the joints radiating to the center C corresponding to the number of arch joints re¬ quired, which in this example is seven. The square bonding d a, f b, g c of vertical and horizontal joints may be of varied sizes. The radiating joints (here shown) are made equal in length from the soffit, and for this purpose from the center C describe a quadrant, cutting the joints at ab c. 287 288 APPENDIX To find the Development of Concave Face. Fig. 3.—Divide the quadrant B K (Fig. 2) into any number of equal parts—in this example seven—and draw the ordinates 1, 2, 3, 4, 5, 6, projecting the same on to the springing line, and transfer these to the segment line B C on plan (Fig. 1) as 1, 2, _ DEVELOPMENTS _ the developed length of B' C' on springing line (which is also equal to C' D' and is half of the inside face) from C to D'; transfer AP 1 ENDIX 2 $} 1', 2', 3', 4', 5', 6 ' from Fig. I, and draw the ordinates of equal height to those of Fig. 2, cutting k fg. 3 at l a , 2 a , 3 a , 4 a , etc., through the points 1“, 2 a , 3 a , 4 a , etc.; draw the half of semi-ellipse, which gives the curve of the arris to the soffit. The length of the joints in Fig. 3 is determined in the same manner as in Fig. 2—namely, by means of ordinates. One joint is here given as an example: From A No. 2 A (Fig. 2) drop a perpendicular cutting the springing line at 2 C; and from 2 C to 2 transfer to 2 C and 2 on the segment line of plan (Fig. 1), and draw radiating lines from 2 C to the center 0, cutting the segment A' C' at 2 d; trans¬ fer the distance from 2 d to 2' on to the springing line (Fig. 3). Set up ordinate and make equal in height to a on Fig. 2 , and from 2 A to A' (Fig. 3) draw joint line, which also radiates from the center C. The moulds required for working each arch block are a bed mould and two face moulds (one to the convex and one to the concave face); these are already set out on plan and in developed elevations, but now require separating. As an example, No. 1 A (Fig. 2) is the springer. For the bed mould take A B 2 and A' B' 2' from plan (Fig. 1), and transfer to 1 C (Fig. 4). The dotted line B B' shows the line of the soffit on the bottom bed, the line a a' the line of the arch joint on the top bed, A A' the line of radiat¬ ing vertical joint, and 2 2 ' the line of arris of the arch joint. This gives the plan of a segment of a hollow cylinder to the extreme size of the stone. No. 1 A (Fig. 4) is the face mould for convex face, No. 1 B (Fig. 4) is the face mould for con¬ cave face, and both of these are transferred from 1 A and 1 B (Figs. 2 and 3), with the addition of the square line 2 2 and 2’ 2'. The stone for the arch block should be large enough to work the bed mould square through; if there is a "wanty” corner in the rough block, this may be arranged for in the corner where the stone has to be cut away for the soffit or the top joint. Work the two beds bottom and top parallel to each other and of the height of the face mou’d, scribe in the bed mould No. 1 C on both beds (to be correct this should be boned in). Fig. 4 . 290 APPENDIX the vertical joint A d being at right angles to the bed. Next work the convex and concave faces through, and also the ra¬ diating joint A A', the block at this stage being a portion of a /iollow cylinder similar to sketch (Fig. 7). Now scribe in the face moulds 1 A on the convex and 1 B on the concave faces (Fig. 4); next work the arch joint a e through (this will have a slight twist); and lastly, for the soffit cut in a draft B e on convex and B' e' on concave faces, and work the surface through, thus completing the springer. It may be observed that the soffit is a winding or warped sur¬ face, and it will be worked similar to the soffit of winder step, as previously described. To work the Second Arch Stone, No. 2 A (Fig. 2). For the bed mould 2 C (Fig. 5), project the extreme points a and 4, No. 2 A (Fig. 2) on to springing line; transfer these to the segment line A C on the plan (Fig. 1). This gives from 2 C to 4 and 2 d to 4', which encloses the bed mould; a a ' is the vertical joint and arris of the arch joint a 2, the dotted line 2 a is the horizontal line of the joint on soffit at bottom, and the line b b ' is the arris at the top of arch joint, 4 4 a is the bottom arris of the top joint to soffit. No. 2 A (Fig. 5) is the face mould for the convex face, and No. 2 B (Fig. 5) is the face mould for the concave face; both of these are transferred from 2 A and 2B (Figs. 2 and 3), with the addition of the square line 4 b, 4 C, and 4 1, 4 2. Work the top bed first / b, 4 b, and take the bottom bed a 2, 4 C parallel to the top and of the height of the face mould (this is a surface of operation, all being cut away except arris 2 2 a, which must be kept true across the bed). Scribe the bed mould No. 2 C (Fig. 5) on both beds. Now work the two faces convex and concave through, and the radiating joint a a’ square with n-r / MOUl I L ; 3C 1 APPENDIX 291 the top bed, bringing it again into the shape of a portion of hollow cylinder ; as in sketch (Fig. 7). Scribe the face mould 2 A on the convex and 2 B (Fig. 5) on concave faces. Work the arch joints a 2 and b 4, and for the soffit cut in the draft 2 4 on the convex and 2 a, 4 a on concave faces, and work through as previously described. The other arch stone 3 A and keystone are worked in a similar manner, the general principles of working being the same. Note .—The radiating joint lines on the developments (Figs. 2 and 3), to be geometrically correct, should not be straight, being slightly curved. This is apparent on cutting a cylinder by a right line obliquely, the development of which is a compound curve; but in this case the curve is so slight as to be scarcely perceptible, and need not in the present and the following ex¬ ample be taken notice of. Fig. 7- Fig. 8. To construct a Semi-circular Arch in a Cylindrical Wall, whose line of soffit on the plan is parallel to the axis, the axes of the two cylinders intersecting each other at right angles. Fig. 9.—Shows the plan of the arch, BCD being the opening. Figs. 10 and 11 are the developed elevations. In order to prevent confusion with Figs. 9, 10, and 11, and to make matters easier of explanation, three diagrams are here shown, containing Fig. 15, Figs. 16, 17, and Figs. 18, 19, these being slightly exaggerated to show more clearly the working. Let Fig. 15 be the plan of segment of cylinder, with the semi¬ cylinder penetrating the same at right angles to the axis at a e, b d. Let Fig. 16 be the square section of the quadrant of cylinder, and divide this into any unequal number of equal parts corre¬ sponding to the number of arch stones required in Figs. 10 and 11, which in this example is seven, as 1, 2, 3, 4, 5, 6 , 7, and pro- 292 APPENDIX ARCHES CIRCULAR on PLAN _ DEVELOPMENTS _ _ HA L. r CONVEX. i HA. LF CONCAVE — ( OUTSIDE ) ■ ( / HS/OE ) ject on to the segment line a cb on plan (Fig. 15), as C 6, 5, 4, 3, 2, 1; transfer this to the springing line ab, 1, 2, 3, 4, 5, 6, 7 (Fig. 17), which is now the developed line; erect ordinates, and make them equal in height to the ordinates of the square section, as 1', 2', 3', 4', etc.; draw line through the intersecting points 1', 2', 3', 4', etc., giving the curve required on the development at the point of penetration for the outside or convex face of cylinder. APPENDIX i 293 For the development of the inside or concave face, let Fig. 18 be the square section, divided into seven equal parts, projecting the ordinates as before. Transfer from Fig. 15 l a , 2 a , 3 a , 4 a , 5 a , 6 “, 7 a to the springing line (Fig. 19), erect ordinates and make them equal in height to those of square section at 1, 2, 3, 4, etc., and through the intersecting points l a , 2 a , 3 a , 4 a , etc., draw the line giving curve required at the point of penetration for the inside or concave face of cylinder. For the joints draw radiating lines at 2, 4, 6 (Figs. 16 and 18), and to make them of equal length draw a quadrant line with radius of the square section as f g h, project / g h on to plan (Fig. 15) as j g h, and transfer to the springing line (Figs. 17 and 19); erect ordinates at / g h, making equal in height to those of the square section. Next draw the joint lines h 2 ', g 4', / c' on Fig. 17, and h 2“, g 4 a , and / c' (Fig. 19); the developed length of joint is thus obtained. To set up the Elevation on the Developments for the Face Moulds. Figs 10 and 11 .—Let AE' be the springing line, CK the center line, and L Iv M dotted line the square section of the cylinder whose center is C. For the development B Iv D proceed as previously described, and divide into any number of equal parts for the arch stones required—which in this example is seven—and draw the joints; the square holding a b, b f. fl may 294 APPENDIX be set out at will, but should be set out from the inside or con¬ cave face, so as to obtain a parallel arch joint. The joint c b', No. 2 C (Fig. 13), which is the arch joint cut¬ ting out to the vertical joint b', illustrates this. The moulds for working each arch block are a bed mould and two face moulds. These are already set out on plan (Fig. 9) and elevations (Figs. 10 and 11), except the addition of a square line to the extreme size. To work the springer: For the bed mould take A c, B d from the plan (Fig. 9) and transfer to 1 C (Fig. 12); the dotted line B B' is line of the soffit on the bottom bed, the line c c' is the line of joint on top bed, the line d d' is the line of arris of the arch joint in soffit, and the line A A' is the radiating vertical joint. No. 1 A (Fig. 12) is the face mould for convex face, and No. 1 B, Fig. 12, is the face mould for concave face; both of these are transferred from 1 A and 1 B (Figs. 10 and 11), with the addition of the square line e e'. Work the two beds (bottom and top) par¬ allel to each other, and of the height of the face mould. Scribe the bed mould No. 1 C (Fig. 12), on both beds, and work the two faces convex and concave through, and also the vertical joint A a, which must be at right angles to beds; this will form a portion of a hollow cylinder similar to sketch, Fig. 7. Now scribe in the face moulds 1 A and 1 B (Fig. 12), on the convex and concave faces respectively, and work the arch joint c d through, and for arrises to the lines, and work drafts parallel to the bed B B' until the whole of the soffit is finished. In this arch the soffit is not a winding surface. To work the Second Arch Stone No 2 A (Fig. 10). Let No. 2 C (Fig. 13) be the bed mould, project the extreme points b h, No. 2 A (Fig. 10), on to springing line A C. This being a developed face, it will require folding back on to the segment line A C E of plan (Fig 9), as b d h, and transfer this to No. 2 C, which gives the bed mould. No. 2 A (Fig. 13) is the face mould for convex face, and No. APPENDIX 295 ARCHES circular on plan 1 296 APPENDIX 2 B (Fig. 13) is the face mould for concave face, and both of these are transferred from 2 A and 2 B (Figs. 10 and 11), with the addition of the square line l. Work the two beds (bottom and top) parallel to each other, and to the height of the face mould. The bottom bed is worked as a surface of operation for the application of the bed mould, and it is all cut away except the arris d d'. Scribe the bed mould 2 C (Fig. 13) in on each bed, and work the two faces convex and concave through, and scribe in the face moulds 2 A and 2 B (Fig. 13). Work the vertical joint b b square with either the top or bot¬ tom beds, and work the bed b c and joint c d; then joint g h, and, lastly, soffit d h. Fig. 14.—Nos. 3 A, 3 B, and 3 C are the face moulds and bed mould of the third arch stone, and together with the keystone are projected and worked in precisely the same manner as the foregoing Nos. 1 and 2 stones. It will be advisable for the student to work small models, which should be constructed to scale in plaster, clay, or other soft material. The moulds for these models may be cut out of stout drawing paper, and in their application will be found the best method of obtaining knowledge of these subjects. SKEW ARCH AND NICHES To construct a Semi-circular Arch Rib, the oblique angle of which does not extend more than ten or twelve degrees from a right angle, the joints being parallel to axis, and in the same planes. This is not a difficult problem, as the arch within these limits may be set out and worked as a right arch; but beyond these a different principle of construction is necessary. Fig. 1.—Shows the elevation of the arch, which is a semi¬ circle. Fig. 2.—Shows the plan of the arch, B G and D J being the opening, B D and G J the inclination or angle of skew, E and F the centers, A and H the outer face line of the arch, and C K the inner face line of the arch. There is no difference in the outer and inner faces of the arch, both being alike, but the terms are here used for purpose of explanation. APPENDIX 297 Project AC, BD and G J, HK from the plan to the spring¬ ing line (Fig. 1), as a c, bd and gj, hk, with e as center, and e a and e b as radius, describe the semi-circles a o h and b m g, for the outside face, and with / as center, and the same radius, describe the semi-circles c p k and d n j, for the inside face. For the joints, divide the arch into any convenient number of equal parts—in this example seven—as qr s t u v on line b m g of intrados, and with the same divisions repeat on the line d n j SKEW ARCH ELEVATION F/C.2 PLAN as q' r' s' t' u' v'; from the center e draw radiating lines through these points, and produce to the outside curve or extrados for .the outside, and for the inside of the arch; repeat the same from the center /. It will be observed that the direction of joints is perfectly horizontal, the lines qq', rr', s s', etc., being level; the radiating lines and joints are also parallel to each other, and are therefore in the same place. This is all the setting out required, with the exception of the joint moulds. 2gS APPENDIX To work the Arch Stones. Fig. 3. —Let No. 1 L be the face mould of the springer and A and B the joint moulds. The face mould 1 L is transferred from the elevation Fig. 1, and the bottom bed or joint mould A, from plan (Fig. 2); for the joint mould B, draw a line parallel to joint e' /', and project e' f and g' h' as e / and g h, of an equal and parallel thickness, as X X at A and B. Work a' b' e' /' outside face of springer No. 1 L, to a plane surface, and cdgh inside, face parallel to it; scribe the face mould into extreme size on each face as a'd' e' g' h f ; scribe in the segment line /' b ’, giving arris of soffit on outside face (this may be done by drawing the mould back, as h! d’ is the same segment and also the same length as /' &') Fig. 3. Fig. 4 . Fig. 5. Work the bottom bed A, which is horizontal, and square with the vertical face, and scribe in the bed mould as abed, which will coincide with the lines on the face mould; now work the top joint B; this from the outside face will be full of the square, or, in other words, it makes an obtuse angle with the vertical face. This, however, is given by the face mould, as e' /' is line of joint on the outside, and g' h' on the inside. Scribe in the joint mould B as e f g h, and work the soffit b'd' }' h' through, as in a right arch, and finish with the back joint a' c ' e' g'. Fig. 4.—No. 2 L is worked similar to No. 1 L; the top joint APPENDIX 299 mould B of No. 1 is the bottom joint mould of No. 2, and the top joint mould C of No. 2 is the bottom joint mould of No. 3, and so on—this is self-evident. The bevels of these joints are found by projecting the points of the face mould, as j k l m, etc., as before described. Begin by working the two vertical faces e f j k and g him parallel to each other, scribe in the face mould No. 2 to the extreme size, as efhjlm, and work both joints B and C; the top joint C is full of the square, whilst the bottom joint B is slack of the square from the outside face, the amount of the obtuse and acute angle being given on the face mould. Fig. 5.—No. 3 L and the keystone are worked precisely simi¬ lar to the foregoing. One set of moulds for one-half of the arch only is required, as the four face moulds and the four joint moulds will work the complete arch; being a plain arch without mouldings, the stones are reversible; this is apparent on looking at the elevation, but should there be an architrave moulding on one face, a mould to each stone is then required. To construct a Spherical Niche in a straight wall with hori¬ zontal splay beds, and with vertical joints. Figs. 6 and 7.—Show the elevation and plan of the niche. Let A E be the face line of the niche on plan (Fig. 7), B D the opening and C the center; with C B or C D as radius, and C as center, describe a semi-circle BKD, which is plan of ex¬ treme size of inside of niche; project ABODE to the spring¬ ing line on elevation (Fig. 6), as abode, and at c erect perpen¬ dicular for the center line. With c as center and c b or c d as radius, describe the semi-circle b k d for the outer curve, and divide this into five equal parts as at / g h i; from c draw radiating lines through these points of division, cutting the horizontal bed at Iran o, giving the joints, the bevel of which will be con¬ tinued horizontally round the niche as at fi and g h. For joints to the plan draw ordinates at fghi and l m, etc., and project them on to line A E on plan (Fig. 7), as F G H I and L M, etc.; at L F M G describe the semi-circles, giving the horizontal line of splay joints. For dividing joints on the plan, take the second course first and divide the line of semi-circle F Q I into four equal parts as P Q R, and from C draw radiating lines through these divisions, producing them on to the line L N O, which gives the joints. The springers 1 L and 1 R in the first course 300 APPENDIX will require to be about half the depth of others in the same course, in order to break the bond (as will be seen by reference to the plan); therefore, on the line B K D, set off, say, little more than half for the two springers as B S and D Y, dividing the remainder into three equal parts as at S T U V, and draw the lines through, radiating from the center to the back, giving the joints in the bottom course. The top course No. 3 is in one stone, and to prevent any tend¬ ency to slip out of its place forward, the upper part of bed may be kept square; this would require notching on the inside, as M M 2 and N M 2 on the plan, and m 4 4 and to 5 5 on the ele¬ vation. The vertical joints are shown on the elevation by projecting up from the plan, as shown by the dotted lines w p x q, etc. APPENDIX 301 To work the Springer. Fig. 8. — 1 A is the bed mould transferred from the plan (Fig. 7), the line A F being the vertical face on the front, F W the horizontal line of arris of soffit and splay joint on the top bed, L O the outside line of splay joint on top bed, the dotted line B S the line of soffit on bottom bed, W W' the line of vertical radiating joint, and A A' the line of vertical face joint. 1 L is the face mould transferred from the elevation (Fig. 6), which will also apply as joint mould at W W'. The form of the stone required to work this will be a wedge- shape prism, containing the bed mould to the extreme size on the top bed as A F W W'; the bottom bed is a little smaller, and is contained within the lines A B S W', and of the extreme height of the face mould from a to a'. Fig. 10 . Begin by working the front vertical face ABF, and scribe the face mould 1 L on, as ah } l a'. Work the vertical joint A A' as a a' square with the front face, and bottom and top beds square with the front face, scribing on the bed mould 1 A, and also the inside vertical joint W W', scribing in the face mould as ah f l a'. It is necessary to work the whole of the top bed, although a portion from l to / 1 will be cut away for the splay joint, in order to get horizontal line F W at /; to obtain this arris, square down the concave line from F to W to the depth at /, or a draft from F to W may be worked by the aid of a template. This being done, trammel the line / parallel to / 1, giving the arris line required; the line L 0 is marked on the 302 APPENDIX top bed with the template, and the splay joint from f to l then worked off. The soffit now remains to be worked; cut in the drafts B S on the bottom bed and F W on the top bed, and drafts b f on the face and joint; a convex template is used as at g for the intermediate drafts, which are cut in as close as con¬ venient, until the v« T hole surface is worked. The template g must not be applied parallel to the joints, but to lines radiating from the center. The three No. 4 stones will be worked similarly to the fore¬ going; one vertical joint is worked first as a surface of operation, instead of the front face as in the springer. To work No. 2 L Stone. Fig. 9.—2 B is the bed mould transferred from the plan (Fig. 7), the line B G being the vertical face on the front, and G Y the horizontal line of the arris of soffit and the splay joint on the top bed, M M' the outside line of the splay joint top bed, the dotted line F P the line of soffit on bottom bed, Y Y' the line of vertical radiating joint, and B B' the line of vertical face joint. 2 L is the face mould, transferred from the elevation (Fig. 6), which will also apply as joint mould at Y Y'. The form of stone required to work this will be a wedge-shape prism, containing the bed mould, to the extreme size as B G YY1, and of the extreme height of the face mould, from / 1 to 6 1. Begin by working the front vertical face, and scribe the face mould 2 L on as b 1 b f g m. Work the vertical joint b b' square with the front face, also the top bed, and scribe the bed mould on. Work the bottom bed as a surface of operation; the only part required being the arris of the splay joint, and soffit F P, the rest of the bed being cut away. This is the easiest and most accurate way of working, but the bed need not necessarily be worked as a whole, a portion only being required, sufficient to obtain the arris line F P; in this case the soffit F G should be worked after the arris line is drawn on the bed, by a convex template made from / to g, and the splay joint is worked from a beveled template made from gfb- The remaining portion of the stone is worked as before de¬ scribed to springer. The two No. 5 stones are worked similarly. APPENDIX 303 To work the Keystone No. 3. Fig. 10.—3 C is the bed mould transferred from the plan (Fig. 7), the line MN being the vertical face on the front, M C 2 N the top line of the splay joint, and G C 1 H the line of arris of soffit, and the splay joint on bottom. No. 3 is the face mould transferred from the elevation (Fig. 6), niche - Eke v * V ° N - Begin by working the vertical face M N, scribing in the face mould as g h m n. Work the top bed through square with the face, scribing in the bed mould, also the bottom bed parallel to the top at extreme points g and h, and with a template scribe G C H the arris of the soffit and the splay joint. Work the joint round tc the splay lines, then the soffit by cutting in the draft g c h on the front, and with a convex template made from C to Cl, complete the surface. 304 APPENDIX The niche need not be jointed as here shown, for much de¬ pends on its size, and the size of the stone convenient to use, but the general principle of working will be the same. To construct a Spherical Niche in a straight wall, with joints radiating from the center. Figs. 11 and 12.—Show elevation and plan of the niche. Let A E be the vertical face line of the niche on the plan (Fig. 12), B D the opening, and C the center. With C B or C D as a radius, and C as a center, describe the semi-circle B K D, which is the plan of extreme size of the inside of niche, and project ABODE to the springing line a e on the elevation (Fig. 11), Fig. 14 . Fig. 13 . as ah c de. At c erect a perpendicular for the center line, and, with c as center and c b or c d as radius, describe the semi-circle b k d for the outer curve. With c y as a radius and c as the cen¬ ter, describe a semi-circle for the center stone which may be of any convenient size. Divide the semi-circle b k d into seven equal parts as fghijl, and through these points of division from c draw radiating lines cutting horizontal beds at m n 0 p, etc., and the center stone at s t u v, etc., which gives the joints. Draw ordinates from f g li i, etc. and project on to the line A B as F G H I, etc., and repeat the same at stuv, etc., on the line Y Z, giving joint lines on the plan; to determine points in the curve of the soffit for templates, the dotted lines at the right hand of the niche show how they APPENDIX 305 are obtained. The dotted segment line from 1 to 1, 2 to 2, 3 to 3, etc., on elevation will be the section of curve at corre¬ sponding points on the plan at 1 1, 2 2, 3 3, etc., and also gives the points in the line of curve for the joints on plan, although the last named is not necessary for the setting out or the work¬ ing. To work the Springer 1 L. Fig. 13.—1 A is the bed or joint mould transferred from the olan (Fig. 12), the line A B being the front vertical face, B Y the line of soffit, Y Y 1 the splay joint, and A A 1 the vertical face joint. No. 1 L is the face mould transferred from the elevation (Fig. 11 ). The form of stone required will be that of a wedge-shape prism (as in sketch, Fig. 14), containing the face mould to the extreme size as a' a y s m. Begin by working the bed or joint ah y, keeping the seg¬ mental line B Y fair for arris, and scribe the bed mould 1 A on. Work the vertical face and scribe in the face mould 1 L, and the other bed m / s, scribing in the bed mould 1 A. Work the vertical joint a a', and top bed a'm, and, lastly, the soffit, the working of this being guided by one or two templates made from 11,2 2, etc. The remaining stones are worked similar to the foregoing, keeping in mind the principle that the stone is contained within the wedge-shape prism, thus making it easy of comprehension. INDEX TO PART I BRICKLAYERS’ GUIDE A Atmospheric action, 16 Asphalt damp courses, 43 Acute squints, 81 Angles of walls, 83 Arches and gauged work, 99 Arches generally, 101 Axed arches, 105 Arches with moulded soffit, 112 Arches springing from one pier, 137 About niches, 138 B Bed joints, 12 Bats, 12 Bonding method of leveling, 21 Bonding walls, 51 Bonding for fireplaces, 52 Best double wall construction, 53 Brick cornices, 60 Brick columns, 61 Brick capitals, 61 Base of columns, 62 Bonding generally, 67 Bond, "What is it?” 67 Bond in brickwork, 67 Brick reveals, 79 Bastard tack pointing, 87 Breasts and flues, 88 Bond in chimney stacks, 94 Bull’s-eye arch, 133 Bricklayer’s tools, 158 Brick cutting tools, 160 Bricklayer’s mortar, 161 Building in frosty weather, 161 Brown mortar, 163 Bricks specified, 164 Bricklayer’s specifications, 164 Brickwork during frost, 177 c Course, 12 Cross-joints, 12 Closers, 12 Concentrated lateral pressure, 16 Clay, 36 Circular damp protection, 45 Cavity walls, 54 Copings, 58 Corbels, 59 Cornices, 60 Chimney breasts and flues, 88 Chimneys of various kinds, 90 Chimney bond, 93 Clustered flues, 96 Catting bricks, 100 Construction, 106 Camber arch, 117 Camber on circle, 122 Curyed work, 123 Cubic measurement, 148 Concrete, 152 Cubing, 149 Chimney breasts, 155 Course mortar, 162 Colored mortar, 162 D Damaging forces, 14 Distributed over-turning pressures, 16 Damp courses, 40 Double wall damp courses, 46 Dry areas, 48 Damp walls, 54 Damp outside walls, 56 Dutch bond, 69 Double flemish bond, 70 Diagonal bond, 76 Double flues, 89 Drawing arches, 129 Damp-proof walls, 175 Drainlayer, 178 Drainage, 180 E Excavation, 17 Embanking, 23 English bond, 68 English cross bond, 69 Examples of single Flemish bond 72 Egg-shaped sewer, 104 Equilateral Gothic arch 125 Elliptical arch, 127 Estimating quantities, 150 Enameled bricks, 165 F Foundations, 13 First method, 18 Foundations, 35 Forms of foundation, 39 Flemish bond, 69 Facing bond, 73 Flat or flush joints, 85 Flat jointed joints, 85 Flues, etc., 88 Fireplace jambs, 91 Fixing and setting niche, 14? 307 308 INDEX Foot run, 147 Foot super, or square, 147 Footings and prices, 171 Fireplaces and chimneys, 172 Facings, 173 Factory chimney shaft, 175 For mechanical engineer, 180 G Gravel, 36 Garden wall bond, 74 Gauged work, 99 Gauged arches, 106 Gauging bricks, 124 Gothic arch, 135 General specifications, 164 H Header, 12 Hindrances, 67 Hoop-iron bond, 73 Herring-bone bond, 76 How to cut a semi-arch, 110 Haunches, 138 How to work a niche, 139 Hollow walls, 157, 174 House drainage, 178 I Inequality of settlement, 14 Instruments, 18 Interior stones, 98 Intersection of haunches, 138 J Junctions of cross-walls, 77 Joints generally, 84 Joints on face, 85 Joints, mortar, 85 Joints and pointing, 170 K Keyed joints, 86 L Lap, 12 Lateral escape, 15 Large cuttings, 26 Leveling of brickwork, 82 Labels to arches and niches, 144 Lime mortar, 166 M Moulded bricks, 64 Moulded bases, 64 Moulded capitals, 64 Moulded stretchers and headers, 65 Mortar joints, 85 Method of carrying the hearth, 92 Mantel registers, 98 Moulded segment, 115 Moulded eambpr, 121 Modified Gothic, 126 Moorish arch, 135 Mode of cutting bricks for a niche, 142 Moulded soffit to niches, 144 Moulded labels, 144 Measurement of brickwork, 146 Methods of measurement, 148 Measuring chimney breasts, 155 Measuring arches, 155 Mortar, 161 Materials, 164 Moulded strings, 165 Mechanical engineer, 180 N Niches, 139 O Obtuse squints, 81 Ogee arch, 136 Oriel windows, 145 Obtaining measurements, 150 Old bricks, 152 P Preface, 9 Plan, 11 Plaster cornices on brick or stone, S' Plinth for column, 63 Plans of squint piers, 81 Plans of squint quoins, 81 Plans of splayed reveals, 81 Pointing old work, 86 Pointing, measurement, 153 Partition walls, 157 Pointing tools, 160 Pressed bricks, 164 Preliminary, 169 Pointing and joints, 170 Piers and footings, 171 Q Quoins, 12 Quoins, squint, 78 Quantities, 150 R Remedies for damp walls, 41 Raking bonds, 75 Reveals, 78 Raking back, 82 Recessed joint, 87 Registers, 98 Relieving arches, 101 Radiating box, 142 Rules for measuring, 147 Retaining walls, 175 S Some definitions, 11 Section, 11 Stretcher, 12 Sliding, 15 Second method, 20 Sinking shaft, 31 Sand, 36 Solution for damp walls, 56 • Single Flemish bond, 72 Splayed jambs, 78 Squint quoins, 78 INDEX 309 Struck joints, 86 Stack of chimneys, 94 Setting hanger, 96 Segmental arches, 108 Setting work, 113 Striking curves, 128 Sleeper walls, 157 Specifications, 164 Salt-glazed bricks, 165 Sand, 166 Sundries, 174 T Third method, 20 Trenching, 22 Timbering for excavations, 23 Tunneling, 34 Timber in foundations, 35 Tied walls, 49 Top copings, 58 Toothings, 80 Tuck pointing, 87 The relieving arch, 101 The invert arch, 103 The semi-circular arch, 106 The segment arch, 115 To set out an arch, 119 The modified Gothic, 126 The elliptical arch, 127 Templates, 131 The scheme arch, 133 The bull’s-eye arch, 134 The semi-Gothic arch, 134 The ellipse Gothic arch, 134 The horseshoe arch, 135 The ogee arch, 136 Two arches from one pier, 137 The niche, 138 The semi-circular niche, 139 The oriel window, 145 Template for niches, 145 Timesing, 151 Taking quantities, 151 Tools employed, 158 Tools for cutting bricks, 160 Technical terms, 161 W Withdrawal of water from foundation earth, 15 Wall copings, 58 Work to be measured, 157 Water, 166 Weather joints, 170 Walls generally, 171 INDEX TO PART II STONEMASONS’ GUIDE A A stonemason—What is he? 181 Axed work, 190 Ashlar, 196 Ashlar rubble, 236 Ashlar facings, 235 Arches and joints, 246 Ashlar, 283 Appendix, 287 Arches, circular or plain 288 A stone niche, 300 B Bond, tap, and course, 182 Bonders, 182 Bed surface, 183 Blocking course, 185 Breasted work, 190 Block in course, 195 Bolts, 199 Bond, 238 C Corbel, 184 Cornices, 185 Coping, 185 Corbel step gables. 186 Corbel table, 186 Chisel drafted margin 189 Combed or dragged work, 191 Circular work, 193 Circular sunk work, 193 Circular circular sunk work, 193 Cramps, 198 Cement joggles, 200 Curved beds, 218 Coping stones, 231 Cornice caps, 253 Classic mouldings, 272 Crowning mouldings, 275 Carving, 284 D Diaper work, 187 Dowels, 200 Dry rubble, 233 Doweling, 241 Dovetail bonding, 242 Definitions, 245 Dovetail joints, 252 Dressings, 282 Developments, 288 E External miters, 173 Elevations and sections of stone walls. 257 Elevations, plans, and sections of windows, 258 Elevations of circular window heads, 259 Elevations of sunk work, 260 Elevations of square windows, 261 Elevations and plan of Gothic windows, 262 Elevations and sections of Gothic doorway, 264 Elevation and plan of niche, 300 F Footings, 183 Finial, 187 Furrowed work, 191 Flush joints, 239 Fjat arches, 248 Fixing stone steps, 267 Floors and steps, 284 G Grout, 182 Galleting, 183 Gable details, 186 Gablets, 186 Gargoyle, 187 Gothic window heads, 262 Gothic joints, 263 Grecian mouldings, 272 Gothic mouldings, 273 H Headers, 182 Half-sawing, 188 Hammer dressing, 189 How to work a stone niche, 303 I Introduction, 181 Internal miters, 193 Irregular rubble. 236 J Joints, 196 Joints to resist compression, 198 Joints to resist tension, 198 Joints to resist sliding, 199 Joggles, 199 Joints 238 Joggling 241 Joggle joints, 249 K Kneeler or skewput, 184 Keystones in circular windows, 260 Keystones in square window heads, 261 310 INDEX L Lacing courses, 184 Lintels, 187 Labors, 188 Lead plugs, 199 Lewis bolts, 206 Large face moulds, 218 Large block ashlar, 226 Lead plugs, their use, 242 Lewis bolts, 256 Laying out a stone niche, 303 M Moulded work, 192 Moulded work, circular, 193 Mixed masonry, 223 Masonry generally, 224 Moulded Gothic windows, 262 Mouldings, classic, 272 Materials, 276 Mechanical engineer, 277 0 Open joints, 240 Other special clauses, 285 Other arches, 286 Open arches, 288 P Plinth, 185 Parapet, 187 Plain work, 189 Polishing, 190 Pointed work, 192 Pebbles, 201 Protecting cut-stone work, 243 Quoins, 183 R Rebated joint, 185 Rubbed work, 189 Returned, mitered and stopped, 193 Random rubble, 194 Random rubble set dry, 194 Random rubble in course, 195 Regular coursed rubble, 195 Rag bolts, 199 Rubble masonry, 220 Rebated V-joints, 228 Rough hammered work, 229 Rubbed work, 230 Raking copings, 231 Rubble ashlar, 234 Rusticated joints, 240 Rebating, 240 Radius, 245 Roman mouldings, 272 S Sparks or shivers, 182 Stanchions, 184 Sills, 184 Saddle or apex stone, 184 Skew corbel, 184 String courses, 185 Saddled or water joints, 185 Self-faced, 189 Scabbling or scappling, 189 Sunk work, 193 Stone walling, 194 Snecked rubble, 195 Squared rubble, 195 Stone-cutting saw, 206 Spatting hammer, 210, Snecked rubble, 237 Securing bolts, 243 Springer, 244 Skewbacks, 244 Span, 245 Stone steps and stairs, 266 Spiral stairs, 269 Stone roof, 270 Stone vaulting, 271 Specification clauses, 276 Stone-worker’s specifications, 279 Special clauses for a church, 282 Sundries, 284 Skew arch, 297 T Technical terms, 182 Through stones, 182 Throatings, 186 Templates, 186 Tympanum, 187 Tailing irons, 187 Tooled work, 190 Tabbing joints, 200 Tools and appliances, 201 Tools used in masonry, 202 Traceried Gothic windows, 262 Tracery, 265 To work arch stones, 289 To scribe stones, 290 To set up elevations, 293 U Unwound random rubble, 194 Unwound snecked rubble, 195 Under-surface, 244 V Vermiculated work, 191 Voussoirs, 244 Vaults, 271 Vaulted roofs, 271 Vaulting, 282 Vertical joints, 282 W Weathering, 182 Window and door jambs, 183 Wrought stone names, 212 Window sills, 231 Window heads, 231 Winding stairs, 268 Workmanship, 277 CONCRETES, CEMENTS, MORTARS, PLASTERS AND STUCCOS PREFACE In introducing this book to American Builders and others who are interested in the use of plasters, stuccos, cements and mortar, I feel that I am doing them a service, as there is no such work, so far as I have been able to discover, published in this country that appeals so directly to the practical workman as the present vol¬ ume does; as I have endeavored to put together as much practical stuff as it was possible to wedge in in a vol¬ ume of this size, and in order to do this, I have gleaned the best things I could find in English, American and other books and journals, to which I have added much drawn from my own experience, and from the experi¬ ences of many practical workmen. I have particularly drawn at length from Miller’s exhaustive work on the subject of plastering and stucco work, and am also indebted to the same source for a number of illustra¬ tions used in PART ONE. I have also drawn from Robert Scott Burns to some small extent, and from an earlier work of my own, and from articles I have fur¬ nished to various building journals during the last thirty years. Part Two is made up partly from my own experience, and partly from treatises on cements and concretes, and from Government Bulletins pub¬ lished in Washing-ton, D. C. The paragraphs and illus¬ trations on reinforced concrete are mostly taken from reports of scientific societies, and from papers read before conventions, and from letters and descriptions prepared by manufacturers and users of Portland ce- 5 6 CEMENTS AND CONCRETES ment, furnished me on application, and from materials gathered from many sources, and, while I have added considerable from my own knowledge of the subject, it may be said that the work is almost a compilation taken from the best authorities on the subjects dis¬ cussed. There is enough material on the subject of concrete floating about in the technical press, of the best kind, to build up three or four volumes of the size of this one, but, in analyzing it, I have sifted it down to the limits of this book, preserving that, which in my judg¬ ment, was best for the practical worker, and leaving out the most of that which might be termed theoretical and, therefore, to a large extent unfit for artisans’ purposes. In making the selections in matters of this kind, the personal factor must necessarily be of more or less value, and I flatter myself that, after a successful build¬ ing experience in various forms, covering a period of over fifty years, my knowledge of the value of any problem pertaining to the building trades is deserving of considerable respect. It is this knowledge, along with some knowledge of cause and effect, and my simple and unvarnished methods of placing building matters before the American workmen, that have made my books so popular, and lured the working public into pur¬ chasing, at this writing, nearly two millions of them. And I have reason to hope that this volume will, like all my previous ones, meet with a reasonable amount of appreciation from those who work, or guide the work of others, in cements, plasters, concretes and stuccos. Fred T. Hodgson. Collingwood, Oct. 15th, 1906. PART I CONCRETES, CEMENTS, PLASTERS AND STUC¬ COS—THEIR USES AND METHODS OF WORKING SAME. INTRODUCTORY This book, or rather compilation, is largely made up of the very best material available on the subjects it proposes to discuss. All the latest improvements and methods in the mixing, proportioning and application of plaster, mortar, stucco and cement will be described and laid before the reader in as simple and plain a man¬ ner as possible. The art of using mortars in some shape or other, is as old as civilization, as we find evidences of its use in ruins that date long before historical times, not only in the older countries of Asia and Europe, but also in the ruins of Mexico, Central America and Peru; and the workmen who did their part, or most of this work, were evidently experts at the trade, for some of the remains of their work which have come down to us certainly show that the work was done by men who not only had a knowledge of their trade, but that they also possessed a fair knowledge of the peculiar qualities of the materials they used. “Plastering,” says Miller in his great w r ork on Mortars, “is one of the earliest instances of man’s power of inductive reasoning, for when men built they plastered: at first, like the birds and the beavers, with mud; but they soon found out a more lasting and more comfortable method, and the 7 8 CEMENTS AND CONCRETES earliest efforts of civilization were directed to plaster¬ ing. The inquiry into it takes us back to the dawn of social life until its origin becomes mythic and prehis¬ toric. In that dim, obscure period we cannot pene¬ trate far enough to see clearly, but the most distant glimpses we can obtain into it show us that man had very early attained almost to perfection in compound¬ ing material for plastering. In fact, so far as we yet know, some of the earliest plastering which has re¬ mained to us excels, in its scientific composition, that which we use at the present day, telling of ages of ex¬ perimental attempts. The pyramids of Egypt contain plaster work executed at least four thousand years ago (some antiquaries, indeed, say a much longer period), and this, where wilful violence has not disturbed it, still exists in perfection, outvying in durability the very rock it covers, where this is not protected by its shield of plaster. Dr. Flinders Petrie, in his ‘Pyra¬ mids and Temples of Crizeh,’ shows us how service¬ able and intelligent a co-operator with the painter, the sculptor, and the architect, was the plasterer of those early days, and that to his care and skill we owe almost all we know of the history of these distant times and their art. Indeed the plasterer’s very tools do yet re¬ main to us, showing that the technical processes then were the same we now use, for there are in Dr. Petrie’s collection hand floats which in design, shape and pur¬ pose are precisely those which we use today. Even pur newest invention of canvas plaster was well known then, and by it were made the masks which yet pre¬ serve on the mummy cases the lineaments of their occu¬ pants. ” The plaster used by the Egyptians for their finest work was derived from burnt gypsum, and was there- INTRODUCTORY 9 fore exactly the same as our “plaster of paris.” Its base was of lime stucco, which, when used on partitions, was laid in reeds, laced together with cords, for lath¬ ing, and Mr. Miller, who has examined a fragment in Dr. Petrie’s collection, finds it practically “three coat work,” about % of an inch thick, haired and finished just as we do now. Plaster moulds and cast slabs exist, but there does not appear any evidence of piece moulding, nor does any evidence of the use of modelled work in plaster exist. That some process of indurating plaster was thus early known is evidenced by the plaster pavement at Tel-el Amarna, which is elaborately painted. The floor of this work is laid on brick; the first coat is of rough lime stucco about 1 inch thick, and the finishing coat of well-haired plaster about % inch thick, very smooth and fine, and showing evidence of trowelling, the set¬ ting out lines for the painting being formed by a struck cord before the surface was set, and the painting done on fresco. It is about 60 by 20, and formed the floor of the principal room of the harem of King Amenhotop IV., about fourteen hundred years before Christ, that is, between three thousand and four thousand years ago. Long before this, plastering of fine quality existed in Egypt, and so long as its civilization con¬ tinued it aided the comfort of the dwellings of its people and the beauty of its temples. Nor was it merely for its beauty and comfort that plaster work was used. Even then its sanitary value was recognized, and the directions given in Leviticus xiv, 42-48, which was probably written about one hun¬ dred years before this date, show that the knowledge of its antiseptic qualities was widely spread, and the practice of it regarded as religious duty. 10 CEMENTS AND CONCRETES Unfortunately there is no direct evidence that the adjacent Assyrian powers of Nineveh and Babylon used plaster work. Possibly the tine clay brought down by the rivers of the Euphrates and the Tigris sufficed for all their purposes. Their records are in it: their illustra¬ tions on the sculptured walls of their palaces are in stone, their painting is glazed on their bricks, and for them there seems to have been but little need for plas¬ ter work, nor do we find until the rise of Grecian art anything relating to our subject. Very early in Greek architecture we find the use of plaster, and in this case a true lime stucco of most ex¬ quisite composition, thin, fine and white. Some has been found at Mycenae, a city of Homeric date. We know that it existed in perfection in Greece about five hundred years before the Christian era. With this the temples were covered externally, and internally where they were not built of marble, and in some cases where they were. This fine stucco was often used as a ground on which to paint their decorative ornament, but not infrequently left quite plain in its larger masses, and some of it remains in very fair preservation even to this day. The Temple of Apollo at Bassae, built of yellow sandstone about 470 B. C., has on its columns the remains of a fine white stucco. Pavements of thick, hard plaster, stained, of various colors, were common in the Greek temples. One of these, that of the Temple of Jupiter Panhellenius at iEgina, built about 570 B. C., is described by Cockerell as existing in the early part of the century, in good condition, though the temple itself was destroyed; and I have seen at Agrigentum plaster existing in perfect state, though scarcely thicker than an egg-shell, on the sheltered parts of a temple built at least three hundred INTRODUCTORY 11 years before our era, whilst the unprotected stone was weather worn and decayed. What care the ancient Greeks bestowed on their stucco may be inferred from Pliny’s statement that in the temple at Elis about 450 B. C., Panaenus, the nephew of Phidias, used for the groundwork of his picture “ stucco mixed with milk and saffron, and pol¬ ished with spittle rubbed on by the ball of the thumb, and,” says he : “it still retains the odor of saffron.” Lysippus, the first of the Greek “realists” in sculpture, was the first we hear of who took casts of the faces of living sitters about 300 B. C., so the art of plaster cast¬ ing must have advanced a good deal by that time, as he made presents of copies to his friends. Afterwards we read of many sculptors who sent smaller plaster models of their works to friends. These were, however, prob¬ ably carved in the plaster rather than cast. Whether the Greeks used stucco for modelling is a somewhat doubtful point amongst antiquarians. From certain passages in classic writers I am induced to think they did. Pausanius, who describes the temple at Stym- phalus, an almost deserted and ruined city when he visited it about 130 A. D., describes the ceiling of the Temple of the Stymphalides, built about 400 B. C., as being “either of stucco or carved wood,” he could not decide which, but his very doubt would imply that stucco or wood were equally common. Now, this ceil¬ ing was ornamented with panels and figures of the harpies—omens of evil, half woman and half bird, with outspread wings. He also mentions a statue of Bac¬ chus in “colored stucco.” Of course these are not defi¬ nite proofs of early Greek stucco modelling, but as the city of Stymphalus had decayed and become depopu¬ lated before 200 B. C., there is certainly presumptive 12 CEMENTS AND CONCRETES evidence of the ancient practice of the art. Again, fig¬ ures of unburnt earth are mentioned in contradistinc¬ tion to those of terra cotta, and sundry other allusions to plastic work occur, which lead me to the opinion that quite early in Greek art this mode of using plaster be¬ gan. At any rate, we know that it was early introduced into Grecia Magna—the earliest Southern Italian col¬ ony of the Greeks; and as colonists invariably preserve the customs and traditions of their fatherland even long after they have fallen into disuse in their native home, we can have no reasonable doubt but this art was im¬ ported rather than invented by them. Thence it spread to the Etruscans of Middle Italy, a cognate people to the Southern Greeks, by whom both plain and modelled stucco was largely used. The Etruscans, as we have seen, were more closely allied to the Greek than the Latin race, but in the course of time these two races amalgamated, the former bringing skill in handicraft, the latter lust of power, and patriotic love of country and of glory, whilst the Grecian element, which blended harmoniously with the first of these, added a love of art. This union, however, took long to ripen to artistic fruitfulness. The practical Etruscan element firstly constructed the roads and the sewers, and gave health to Rome. The Latins added to their territory until it em¬ braced half of Europe, giving wealth to Rome, and not till the luxury and comfort thus created did the artis¬ tic element of the Greek come in, giving beauty to Rome, and the day of decorative plaster work ap¬ proached its noontide glory, making Rome the attrac¬ tion of the world. The absorbance of Greece as a Roman province took place B. C. 145, and the loot of it began, giving an enormous impetus to Roman art. Thousands of statues were brought to Rome, and to INTRODUCTORY 13 be deemed a connoisseur in things artistic or a patron of the arts became the fashionable ambition. But it was not until the century just preceding the Christian era that it became especially noteworthy. Of course there is hardly anything left to us of the very early plaster work of Rome. The constant search for some new thing was inimical to the old. Old structures were pulled down to make way for new, which in their turn gave way to newer, and until the age of Augustus we have but little of the early work left. Strabo, who visited Rome about this time, complains of the destruc¬ tion caused by the numerous fires, and continued pull¬ ing down of houses rendered necessary, for even pull¬ ing down and rebuilding in order to gratify the taste is but voluntary ruin; and Augustus, who boasted that “he found Rome of brick and left it of marble,” in replacing the brick with marble destroyed the plaster work. How that plaster work was wrought we shall learn more from Vitruvius, who wrote his book on archi¬ tecture about 16 B. C., and dedicated it to the emperor, “in order to explain the rules and limits of art as a standard by which to test the merits of the buildings he had erected or might erect.” Now, Vitruvius was a man who had travelled and seen much. He was with Julius Caesar as a military engineer in his African campaign in 46 B. C., or ten years after Caesar’s invasion of Britain. Afterwards he became a designer of military engines, what we should call head of the Ordnance Department, and also a civil engineer, persuading himself that he had a pretty taste in architecture, just as though he were an R. E. of today. Thus he had a practical and also an artistic training, and here is what he says on matters connected with plaster work in Book VII, Chapter 11. 14 CEMENTS AND CONCRETES On tempering lime for stucco: “This requires that the lime should be of the best quality, and tempered a long time before it is wanted for use; so that if any of it be not burnt enough, the length of time employed in slak¬ ing it may bring the whole mass to the same consist¬ ency.” He then advises it to be chopped with iron hatchets, adding that “if the iron exhibits a glutinous substance adhering to it, it indicates the richness of the lime, and the thorough slaking of it.” For cradling out, and for ceiling joists, he recommends “the wood to be of cypress, olive, heart of oak, box and juniper,” as neither is liable to “rot or shrink.” For lathing he speci¬ fies ‘ ‘ Greek reeds bruised and tied with cords made from Spanish broom,” or if these are not procurable “marsh reeds tied with cords.” On these a coat of lime and sand is laid, and an additional coat of sand is laid on to it. As it sets it is then polished with chalk or marble. This for ceilings. For plaster on wall he says: “The first coat on the walls is to be laid on as roughly as possible, and while drying, the sand and coat spread thereon. When this work has dried, a second and a third coat is laid on. The sounder the sand and coat is, the more durable the work will be. The coat of marble dust then follows, and this is to be so prepared that when used it does not stick to the trowel. Whilst the stucco is drying, another thin coat is to be laid on: this is to be well worked and rubbed, then still another, finer than the last. Thus with three coats and the same number of marble dust coats the walls will be solid, and not liable to crack. The wall that is well covered with plaster and stucco, when well polished, not only shines, but reflects to the spectators the images falling on it. The plasterers of the Greeks not only make their stucco work hard by adhering to these direc- INTRODUCTORY 15 tions, but when the plaster is mixed, cause it to be beat¬ en with wooden staves by a great number of men, and use it after this preparation. Hence some persons cut¬ ting slabs of plaster from ancient walls use them for tables and mirrors.” (Chapter III.) You will see by these remarks the great care taken through every process, and how guarded the watchful¬ ness over the selection of materials, and you will also note the retrospectiveness of Vitruvius’ observation, how he felt that the work done before the frantic haste of his own time was the better: very much as we find now. Time is an ingredient in all good work, and its substitute difficult to find. There are other “tips” contained in this work which are worth extraction, as, for instance, his instructions as how to plaster damp walls. In such case he prima¬ rily suggests a cavity wall, with ventilation to insure a thorough draught, and then plastering it with “pot¬ sherd mortar,” or carefully covering the rough plaster with pitch, which is then to be “lime whited over,” to insure “the second coat of pounded potsherds adhering to it,” when it may be finished as already described. Further, he refers to modelled plaster work which, he says, “ought to be used with a regard to propriety,” and gives certain hints for its appropriate use. Speak¬ ing of pavements “used in the Grecian winter rooms, which are not only economical but useful/’ he advises “the earth to be excavated about two feet, and a foun¬ dation of potsherd well rammed in,” and then a “com¬ position of pounded coal lime, sand and ashes is mixed up and spread thereover, half foot in thickness, per¬ fectly smooth and level. The surface then being rubbed with stone, it has the appearance of a black surface,” “and the people, though barefoot, do not suffer from 16 CEMENTS AND CONCRETES cold on this sort of pavement.” Now all this bespeaks not only theoretical knowledge, but practical observa¬ tion and experience, and was written nearly two thou¬ sand years ago, from which you can surmise how far advanced practical plastering had then become. This written evidence is almost all we have of the work of Vitruvius’ own time, for even of the time of Augustus hardly anything remains to us, as the great fire of Nero utterly destroyed the greater part of the city in the year A. D. 64, and almost the only authenticated piece of plaster work done before or during his reign is the Tabula Iliaca, a bas-relief of the Siege of Troy, still preserved in the Capitol Museum at Rome. That this was modelled by Greek artists is proved by the fact that its inscriptions are all in the Greek language, and by some it is considered to be of very much greater an¬ tiquity. So much for the ancient history of the art of plastering, and I trust I will be pardoned if I con¬ tinue this sketch, bringing it down to a more recent period and show in what high respect the plasterers ’ art was held in the Sixteenth Century, and later. Quoting from an old work, giving an account of the institution of ‘‘The Worshipful Company of Plaisterers,” and mak¬ ing use of the quaint language then in use we are told that: ‘ ‘ The Plaisterers ’ Company, which ranks as forty-sixth among the eighty-nine companies, was in¬ corporated by King Henry VII., on March 10, 1501, to search, and try, and make, and exercise due search as well in, upon, and of all manner of stuff touching ami concerning the Art and Mystery of Pargettors, com¬ monly called Plaisterers, and upon all work and work¬ men in the said art or mystery, so that the said work might be just, true, and lawful, without any deceit or fraud whatsoever against the City of London or suburbs INTRODUCTORY 17 thereof. The Charter gave power to establish the Com¬ pany as the Guild or Fraternity in honour of the Blessed Virgin Mary, of men of the Mystery or Art of Pargettors in the City of London, commonly called Plaisterers, to be increased and augmented when neces¬ sary, and to be governed by a Master and two War¬ dens, to be elected annually. The Master and Wardens and brotherhood were to be a Body corporate, with per¬ petual succession and a common seal, and they were empowered to purchase and enjoy in fee and perpet¬ uity lands and other possessions in the City, suburbs and elsewhere. And the charter empowered the said Master and Wardens to sue and be sued as “The Mas¬ ter and Wardens of the Guild or Fraternity of the Blessed Mary of Pargettors, commonly called Plaister¬ ers, London.” the old coat of asms* The Company under the powers to make examina¬ tions, appears to have inflicted fines on offending par¬ ties for using bad materials, and for bad workmanship. Search days appear to have been annually appointed up to 1832, but not since, and the Company has not exercised any control over Plaisterers’ work for many years. 18 CEMENTS AND CONCRETES Another charter was granted by Queen Elizabeth in 1559, but it has been lost, and there is no record of the contents. The Queen granted a new charter in 1597, which confirmed the privileges of the Company, and extended the authority of the Master and Wardens to and over all persons exercising the art of plaisterers, as well English as aliens and denizens inhabiting and exercising the said art within the City and suburbs and liberties, or within two miles of the City. THE PRESENT COAT OF ARMS. Charles II., by a charter dated June 19, 1679, con¬ firmed the privileges granted by the previous charters. Having in view the rebuilding of the City, he forbade any person to carry on simultaneously the trades of a mason, bricklayer or plaisterer, or to exercise or carry on the art of a plaisterer without having been appren¬ ticed seven years to the mystery. The jurisdiction of the Company was extended to three miles’ distance from the City. There were two orders made by the Court of Aider- men (exemplified under the mayoralty seal, April li INTRODUCTORY 19 1585) for settling matters in dispute between the tilers and bricklayers and the plaisterers as to interfering in each other’s trades. The observance of these orders Avas enforced by an order of the Privy Council dated June 1, 1613, and a general writ or precept issue to the same effect on August 13, 1613. There was also an order of the Court of Aldermen (29 Elizabeth, February 14, 1586-7) relating to the number of apprentices to be kept by members. An act of Common Council was passed, under date of 18 James I., October 5, 1620. An act of Common Council (6 William and Mary, October 19, 1694) was also passed to compel all persons using the trade of plaisterer in the City of London, or 20 CEMENTS AND CONCRETES the liberties thereof, to become free of the Company under penalty to be recovered as therein mentioned. In the East the Art of ornamental plastering was well known and almost universally practiced before Mahom¬ et established a new order of things, and the enriched plaster work of India, Persia and other Eastern Em¬ pires are evidences of the high character of the work¬ manship of the Oriental workers in plaster. The Arabian and Moor brought back the Art of the Western World in the early part of the thirteenth century, and it is to them we owe the splendid plaster work of the Alhambra and other work still in existence in Spain. In the Mosque at Medina, built in 622, are still to be seen some fine specimens of old plaster work that was wrought on the building at the time of its completion. The Mosque of Ibu-tubun, Cairo, Egypt, which was fin¬ ished in A. D. 878, abounds with beautiful plaster work. It contains a number of arches and arcades, the capi¬ tals of which, like the rest of the building,' are enriched with plaster buds and flowers made in elaborate de¬ signs. Even in Damascus, that old and far-off City indulged in ornamental plaster-work when the people of Western Europe were cutting one another’s throats for political ascendency. We illustrate a few examples of old work taken from existing specimens. These will to some extent, give an idea of what the old plasterers could do. See illustrations attached. During the middle ages in Europe plastering and stucco existed only as a craft, and its highest function was to prepare a surface to be painted on. Sometimes it was used as an external protection from the weather but rarely was it employed for direct ornament. Some¬ times small ornaments were carved in plaster of Paris, but it played no important part in decorative Art, INTRODUCTORY 21 excepting perhaps, as gesso, though this belonged rather to the painter than the plasterer. Nor was it until the commencement of the Renaissance in Italy that it showed any symptoms of revival. ■Arabesque from the Great Mosque, Damascus. With the commencement of the fifteenth century old learning and old arts began to be studied, the discovery of the art of printing and the consequent multiplication of the copies of the lore heretofore looked up in old manuscripts gave invention and progress new life, 22 CEMENTS AND CONCRETES which has lasted until the present day. Italy has al¬ ways been the nursing mother of plasterers, and in Mr. G. T. Robinson’s “Glimpse of the History of the Art and Craft,” he has shown something of her great and glorious past, and how she sent her sons over almost all Europe to raise the art and status of this craft. Persian Centre-Piece. Even during the depressing times of her history she religiously preserved its ancient traditions and pro¬ cesses, and in almost all her towns there was some one or two plasterers to whom was confided the restoration, the repair and the conservation of its frescoes or its stuccos. The art dwindled, but it survived. So late as 1851 an English architect, when sketching in the INTRODUCTORY 23 Campo Santo at Pisa, found a plasterer busy in lov¬ ingly repairing portions of its old plaster work, which time and neglect had treated badly, and to whom he applied himself to learn the nature of the lime he used. So soft and free from caustic qualities was it that the painter could work on it in true fresco painting a few days or hours after it was repaired, and the modeller used it like clay. But until the very day the architect was leaving no definite information could he extract. At last, at a farewell dinner, when a bottle of wine had softened the way to the old man’s heart, the plas¬ terer exclaimed, “And now, signor, I will show you my secret!” And immediately rising from the table, the two went off into the back streets of the town, when, taking a key from his pocket, the old man unlocked a door, and the two descended into a large vaulted base¬ ment, the remnant of an old palace. There amongst the planks and barrows, the architect dimly saw a row of large vats or barrels. Going to one of them, the old man tapped it with his key; it gave a hollow sound until the key nearly reached the bottom. “There, sig¬ nor! there is my grandfather! he is nearly done for.” Proceeding to the next, he repeated the action, saying: ‘ ‘ There, signor! there is my father! there is half of him left. ’ ’ The next barrel was nearly full. ‘ ‘ That’s me! exclaimed he; and at the last barrel he chuckled at finding it more than half full: ‘ ‘ That’s for the little ones, signor! ’ ’ Astonished at this barely understood explanation, the architect learned that it was the cus¬ tom of the old plasterers, whose trade descended from father to son for many successive generations, to care¬ fully preserve any fine white lime produced by burning fragments of pure statuary, and to each fill a barrel for his successors. This they turned over from time to 24 CEMENTS AND CONCRETES time, and let it ain—slake in the moist air of the vault, and so provide pure old lime for the future by which to preserve and repair the old works they venerated. After-inquiries showed that this was a common prac- Portion of a Ceiling from Teheran, Persia. tice in many an old town, and thus the value of old air-slaked lime, such as had been written about eighteen hundred years before, was preserved as a secret of the trade in Italy, whilst the rest of Europe was advocating INTRODUCTORY 25 the exclusive use of newly burnt and hot slaked lime. Was there in the early part, indeed even in the middle Diapered Plaster Panem.ikg in the Aihamhra, Spain. Thirteenth Century. of the present century, any plaster image seller who was not an Italian? Indeed, at this present time, almost 26 CEMENTS AND CONCRETES all the “formatore” or piece moulders for the majority of the sculptors of Europe are of Italian nationality or descent, and chiefly by these has the national craft been maintained. i When after the long European wars of the eighteenth and the commencement of the nineteenth century Italy had rest and power to “make itself” (faro de se), the first revival of its industry was felt by her plasterers, and as there was then, as now, more workmen than Plaster Frieze in Moss, arrises, etc., and make good to all mantelpieces; cut away for and make good after all other trades, and cut out and make SPECIFICATION CLAUSES 45 good all cracks, blisters, and other defects, and leave plaster work perfect at completion. 15. Ding walls where shown on plans with a coat of Portland cement 1 part, sand 2 parts, pea-grit 1 part, and ground chalk 1 part. Finish walls where shown with a rough coat of Portland cement 1 part and sand 3 parts, and rough cast with fine pea-grit. 16. Stop and twice lime white soffits and walls of .. 17. Twice distemper white all ceilings, soffits, and cornices, and twice distemper to approved tints the walls of all rooms. PREPARATION OF BILL OF QUANTITIES. MATERIALS. Materials and Plant, etc. —1 to 7. These items ap¬ pear in the heading under Specification clauses. WORKMANSHIP. Ceilings, Partitions, and Walls. —8 and 10. These are all billed at per yd. super, including lathing where required, also hacking concrete and any dubbing in the latter, stating the thickness. Keep all plaster work less than 12 in. wide separate in “narrow widths.” Wirelathing. —9. These being narrow, it is advisable to measure them at per ft. run, stating the width. Cornices. —11. Cornices and mouldings under 12 in. girt are measured at per ft. run and those over this girt at per ft. super, number all mitres, stoppings, etc.; those to the running items following same, and those to the superficial items averaged for girt. See whether bracketing is required; if so, take the girt required at per ft. super., numbering angle brackets to mitres and returned ends, and averaging the girt. Measure the walls and ceilings less by the height and projection of the cornice, and add to the girt of the cornice 2 in. (i. e., 1 in. for each edge) for the portion ' up to the ceiling and walls. Enrichments are measured at per ft. run, giving the girt and description, and including the modelling. If 46 BILL OF QUANTITIES 47 of exceptional character, a provision for modelling is sometimes inserted. Angles. —12. These appear in bill in feet run with the girt of moulding or bead (if any) and also the widths of returns. Number the stops, mitres, etc., al¬ lowing each to follow the item to which they apply. The finishings to concrete beams, lintels, etc., is kept separate as in “narrow widths to beams, etc.,” and all arrises, etc., being measured at per ft. run. Skirtings or Dadoes. —13. Describe skirtings or dadoes giving height and projection, and also finish at top, and measure at per ft. run, numbering all mitres, ends, etc. Include the dubbing with the item. The general wall plastering is deducted for these. Floating for mosaic and tile pavings appears in the bill in yard super. Quirks. —14. Labor to splays, quirks, arrises, etc., are measured at per ft. run. The attendance on trades is frequently measured in detail, as “making good around mantels” or gratings, etc. The cutting-out and making good appears at the end of the bill in the form here given. Rough Cast. —15. As clauses 8 and 10. Lime Whiting and Distempering.—IS and 17. These appear in the bill in yd. super. In the case of distem¬ pering, if the colors are in any way special mention this, and also if in dadoes and filling, taking the di¬ viding line in feet run. Distempering on cornices is usually measured in ft. super., stating the number of tints, and if lines picked out in ft. run; as is also distempering on enrichments, taking the latter as “extra to,” the distempering to cornices being measured over enrichments. 48 CEMENTS AND CONCRETES LATHS GENERALLY. General opinion is undoubtedly in favor of split laths, and split laths are sometimes specified by archi¬ tects for ceilings and partitions. Sawn laths, unless cut from specially selected straight-grained stuff, would most assuredly have weak places from uneven grain, and in order to avoid this weakness the sawn laths would have to be made thicker than split laths, and only the best quality should be used. Oak laths, for¬ merly used, are very liable to warp. The defects that are to be avoided in laths are sap, knots, crookedness, a,nd undue smoothness. The sap decays; the knots weaken the laths; the crookedness interferes with the even laying on of the stuff, and the undue smoothness does not give sufficient hold for the plaster on the lath. Riven laths, split from the log along its fibres, are stronger than sawn laths, as in the latter process the fibres of the wood are often cut through. Sawn laths are, however, cheaper than riven laths, and have super¬ seded them, which is not desirable in good work. Thick laths, because of the strain upon them, should be used in the ceilings, and the thinner laths should be used in vertical partitions, etc., where the strain is but small. Some walls and partitions have to stand rough usage; in such cases the thicker laths are necessary. Laths are usually spaced with about % in. between them for key. A bunch of laths usually contains 360 lin. ft. and such a bunch nailed with butt joints, covers about 4^2 super, yd., and requires about 400 nails if the laths are nailed to joists 16 in. from center to center. The length of laths varies from 3 ft. to 4 ft. Laths are best nailed so as to break joint entirely, because, for various reasons, there is a tendency to crack along the line of the joints BILL OF QUANTITIES 49 if the laths are nailed with the butt ends in a row. This may be obviated by breaking- joints; ceilings are much stronger if the laths are nailed in this way. Laths, however, are usually nailed in bays, about 4 ft. or 5 ft. deep. Every lath should be nailed at each end, and also at the place where the lath crosses a joist or stud. Lap joints at the end of laths, which are often made in or¬ der to save nails, should not be allowed, as this leaves only 14 in. for the thickness of plaster. Butt joints should always be made. Joists, etc., that are thicker than two in., should have small fillets nailed to the un¬ der side, or be counter lathed, so that the timber surface of attachment may be reduced to a minimum and the key not interfered with. Lathing nails are usually of iron, and are galvanized, cut, wrought, or cast; where oak laths are used, the nails should be oxidized or wrought. Oxidized nails should also be used with white cement work. Zinc nails, which are expensive, are used in very good work, be¬ cause of the possibility of the discoloration of the plas¬ ter by the rusting of iron nails. The length of lathing nails depends on the thickness of the laths, % in. nails being used for single laths, and 114 in. nails for double laths. TOOLS AND APPLIANCES USED BY THE PLASTERER. The illustrations shown at Figs. 1 and 2 show a num¬ ber of tools and appliances made use of by the plas¬ terer, and others—special—will be shown further on, when it is necessary to describe and illustrate some special process or method of working. The tools the plasterer requires are many and varied, and may be enumerated about as follows: They consist of moulds for running cornices, and center moulds, which may never be used only in the one piece of work, as the de¬ signs and styles of cornices and centers are continually changing. As these tools do not cost much, however, the changes do not fall heavily on the workman; but it is as well, whenever it can be done, to charge each mould against its own particular job of work. A good spade and shovel will be absolutely necessary to the plasterer’s outfit, and will be-among the first tools he will require. These should be light and strong, and well handled, or helved; after using they should have all the lime and mortar cleaned off them, and should be placed away where they will not be exposed to the weather. The following list and descriptions of tools will give a new beginner an idea of the kind and character of tools he will be likely to require before he can success¬ fully carry on the plastering business. Most of these tools will be illustrated further on: The Hoes and Drags .—These are tools so well known that they require no description here. They are used 50 TOOLS AND APPLIANCES 51 ON 52 CEMENTS AND CONCRETES chiefly for mixing hair in the mortar, and for loosening mortar when too ‘‘stiff,” or when it has developed a tendency to “set.” They are also used for preparing “putty” and fine “stuff.” (See Fig. 2.) The Haivk, which is a square board about thirteen inches square, with a short handle on the under side. It is used for holding stuff while the operator is at work. It is generally made of pine or some other light wood; it is made thin on the edges, being beveled from the center on the under side to each of the four edges; the handle should be about six inches long, and one and a half inches in diameter. The Mortar-Board is a board similar to a table top, and is about forty inches square; it is made by joint¬ ing two or more boards together, which are secured by two battens, and screws or nails. It is used for holding the mortar delivered from the hod direct by the laborer. Trowels, which are of two kinds: the ordinary trowel, which is formed of light steel four inches wide and about twelve inches long; this is the laying and smooth¬ ing tool, and is the most important in a plasterer’s out¬ fit. The other is termed a gauging trowel, and is used for gauging fine stuff for courses, etc.; it varies in size from three to seven inches in length. Of Floats, which are used for floating, there are three kinds, viz.: the darby, which is not a proper float, is single or double, as may be required; the single being for one man to use, the double for two. The single one should be four feet five inches long, and about four inches wide, with a handle near one end, like a hawk handle, and a cleat near the other end running length¬ wise of the blade; the long darbys have a hawk handle on each end. The hard float, which is used in finishing, and the quick float, which is used m floating angles. TOOLS AND APPLIANCES 53 S-fend floof Al&rg/n 7ro^&/. Modelling Tools NO. 2. 54 CEMENTS AND CONCRETES The hard float is made of good pine, and has a semi¬ circular handle on the back; a strip of hard wood is sometimes dovetailed into the blade, and the handle is screwed fast to the strip previous to the latter being driven in the dovetail; this is a good way, as there are no nails then driven through the blade, which, by the rapid wearing of the latter, would soon project above the blade and scratch the plaster where it was intended to have it smooth. The quick float is seldom used in this country; it is shaped like the angle it is intended to work down, and is a trifle handier for this purpose than the ordinary hard float. Moulds .—These are used for running stucco cornices, and are infinite in shape and variety. The reverse of the contour of the cornice is cut out of sheet copper or iron, and is firmly attached to a piece of wood which is also cut out the reverse shape of the intended mould¬ ing. Their uses will be explained under the head of Operations. Moulds or matrices for leaves, flowers, or other ornaments are made of plaster and glue, or bees¬ wax; these will be discussed hereafter. Center-Moulds are made on the same principle as the reverse moulds for linear cornices, with an arm at¬ tached which is perforated at different radii to suit the diameter of center-piece. Sometimes the moulds for cornicing are so formed, by placing the plates at an an¬ gle of forty-five degrees, that they will finish the cor¬ nice right into the angle and form the mitre; more fre¬ quently, however, the mitres are finished by hand. The Pointer is nearly the same shape as a bricklayer’s trowel, but it is not so large, being only about four inches long. It is chiefly used for small jobbing, or mending broken or defective work. TOOLS AND APPLIANCES 55 The Paddle is simply a piece of pine wood less than three inches wide and six long, by one thick; it is made wedge shaped on one end, the other end being rounded off for a handle. Its use is to carry stuff into angles when finishing. Stopping and Picking-Out Tools, or, as they are fre¬ quently called, Mitering Tools, are made of fine steel plate, seven or eight inches long, and of various widths and shapes. They are used for modeling, and for fin¬ ishing mitres and returns to cornices by hand where the moulds cannot work. Mitering-Rod. —This is a tool one foot or more long, and about one-eighth of an inch thick, and three inches wide; the longest edge is sharp, and one end is bev¬ elled off to about thirty degrees. It is used for clean¬ ing out quirks in mouldings, angles, and cornices. The Operator also requires a good whitewashing brush with a short handle. The best should be ob¬ tained, as it will prove the cheapest in the end. A Scratcher is generally made of short pieces of pine two inches wide and one inch thick; three or four of them are nailed to two cleats, and are placed about an inch apart. The center slat should be about eighteen inches longer than the others, so as to form a handle.' See illustrations. The slats on the opposite end to the handle should be cut off square with one side and point¬ ed. Its use is to make grooves, or bond in what is called the scratch coat. When completed it has somewhat the appearance of a gridiron. Hod. —This is formed by two boards, eleven and twelve inches wide, respectively, and eighteen inches long, the wide board being nailed on the edge of the narrow one, making a right-angled trough; one end is closed, and the end piece is rounded over the top; the 56 CEMENTS AND CONCRETES boards forming the sides are rounded at the opening. A handle about four feet long and two inches in diam¬ eter is then fastened about two inches forward of the middle nearer to the open end, and a piece of wood called a pad is fitted with a groove on the angle just back of the handle. The object of this block is to pre¬ vent the arris of the hod from chafing the shoulder of the laborer. Much controversy has taken place among workmen at various times regarding the exact size of hod, but this, I think, should be governed more by the strength of the person who has to use the particular hod than by any fixed rules. Hods for carrying mortar need not be so large as hods intended for carrying bricks. (See No. 2, Fig. 1.) Sieve .—This is used for straining through putty for finishing; it requires to be very fine for the purpose. Sometimes a hair sieve is used, but they are not last¬ ing, and should never be used when a wire sieve is ob¬ tainable. Sometimes a hair sieve may prove convenient where dry plaster or cements have to be run through a sieve of some kind before it can be used; so, on the whole, the plasterer who desires a full and complete outfit, should provide himself with one good hair sieve, and at least two sieves of wire. (See Fig. 7, No. 1.) Sand Screens are usually twenty-one inches wide in¬ side by about six feet long. On small work they are stood up at an angle of forty-five or more degrees, and the sand is shovelled against them; in some large works the screen is suspended, and one man shovels in the sand and a second one swings or shakes the screen. These screens, to be lasting, should have their sides and ends made of sheet iron, and the bottom should be formed with parallel rods of small round iron having wires running across them at regular intervals. These TOOLS AND APPLIANCES 57 cross wires should be attached to the iron rods so as to hold them in place. The parallel rods may be placed at such distances from each other as will be most con¬ venient for the work in hand. Mortar Beds are made of rough lumber of any kind, and should be built partly in the ground, where cir¬ cumstances will permit. They require to be strongly put together, as they have considerable weight to sus¬ tain. The writer has seen mortar beds built up with bricks and cement where large works have been under construction. Sometimes, master workmen, who do a large business, and who employ a great number of men, keep a large mortar bed or two in the rear yard of their shop and tool house, in which they keep always cn hand a supply of ready-made stuff, which enables them to do small jobs or repairs at a moment’s notice. The Slack Box .—This is generally made of boards, and is eight or nine feet long, and from two to four feet wide, and twelve or sixteen inches in depth. An opening about eight inches square is left in one end, with a slide door attached, so that it can be opened or closed at pleasure. The opening should be covered on the inside with a grating, so that when the lime is run off no lumps or stones will get through. The grating may be made with iron rods, or may be formed with wooden laths or slats. The bottom of the box should be made as close and tight as rough boards will permit. (See No. 1, Fig. 11.) Lathing .\—It frequently happens in towns and coun¬ try places that the plasterer has to do his own lathing, or at least have it done under his own supervision, therefore it will be necessary to have something to say on this subject, and on the tools employed by the work¬ man whose duty it is to prepare the walls for the plas- 58 CEMENTS AND CONCRETES terer. These tools need not be extravagant ones or many in number. They consist of the following: Lather’s Hatchet .—This is a small hatchet with a blade not more than one and a half inches wide, and rather larger in proportion than ordinary hatchets. The opposite end to the cutting edge is a hammer, with which the lather drives the nails. Sometimes the face of the hammer end is grooved, which makes it cling to the nails if the latter are not struck fairly on the head. An expert lather, however, will prefer a flat hammer face for driving lath nails. The cutting edge is used for ‘‘nipping’’ off laths when they are too long, or when short spaces of lathing are required to be made. In cutting lath with the hatchet, the workman gives the wood a short sharp blow with the tool at the point where the severance is required, and the lath is in¬ variably cut at the first blow, if the operator is an ex¬ pert. (See 0, Fig. 2.) Nail Pocket .—Perhaps the best nail pocket a lather can have is made from a portion of an old boot leg cut off to about four inches deep, and having a bottom of semi-circular shape made of wood, and to which the portion of the boot is fastened by means of broad-head¬ ed tacks. The pocket is fastened to the workman’s waist by means of a strap, or other suitable device, and hangs in front of him in a convenient position. Some¬ times nail pockets are made of canvas, but these are not so handy, as the top is apt to close and then nails are difficult to get at. This never occurs with the boot leg pocket. Cut-off Saw .—A cross-cut saw is an indispensable tool to the lather for cutting lath in larger quantities for short spaces, and for rigging up platforms to work on, and for cutting supplementary studding or strips TOOLS AND APPLIANCES 59 where such are necessary. The saw should have rather coarse teeth and have plenty of set. Usually, the lather thinks that almost any old used-up saw is good enough for this purpose, and we find him struggling away with all his strength cutting through a bundle of lath, when, if he had a saw that was worth anything—as a saw— he would perform his labors with about one-half the effort, and one-third of the time. It is all wrong to think of being able to work satisfactorily with inferior or imperfect tools. There is no economy in using tools of this kind, and any lather who fancies he is going to make or save anything by making use of an old buckled, mortar-stained saw, makes a terrible mistake. Get a good saw and keep it in good order, and it will pay you in two weeks. (See X, Fig. 2.) Besides these enumerated, there are many other tools and appliances that the plasterer will require, such as jointing rules, moulding knives, modelling tools, drags, chisels, com¬ passes, plumb rules, etc. PLASTER, LIME, CEMENTS, SAND, ETC. Plaster of Paris. —Gypsum, from which plaster of Paris is made, is a sulphate of lime, and is so named from two Greek words—ge, the earth; and epsun, to concoct, i. e., concocted in the earth. In Italy it is known by the name of gesso; in Scotland it is called stucco; in this country it is known as calcined plaster; and in the English trade as plaster. The term “plas¬ ter” will henceforth be used in this book. The writings of Theophrastus and other Greek authors prove that the use of plaster was known to them. A stone, called by Theophrastus gypsos, chiefly obtained from Syria, was used by the ancients for converting into plaster. Gypsum is mentioned by Pliny as having been used by the ancient artists, and Strabo states that the walls of Tyre were set in gypsum. The Greeks distinguished • two kinds—the pulverulent and the compact. The lat¬ ter was obtained in lumps, which were burnt in the fur¬ naces, and then reduced to plaster, which was used for buildings and making casts. Gypsum is found in most countries—Italy, Switzer¬ land, France, Sicily, The United States, and some of the South American States; also in Newfoundland and Canada. The latter is said to be the finest deposits in the world. It is found in England in many places. The finest gypsum is called “alabaster,” and is soft, pure in color, and fragile. This white translucent ma¬ terial is a compact mass of crystalline grains, and is used for making small statuary, vases, and other ornaments. Gypsum is found in immense quantities in the tertiary 60 PLASTER, LIME, ETC. 61 strata of Montmartre, near Paris. This gypsum usual¬ ly contains 10 per cent, of carbonate of calcium, not al¬ ways in intimate union with the sulphate, but inter¬ spersed in grains. This sulphate gives the Paris plas¬ ter some of its most useful properties. Pantin, near Paris, has large beds of gypsum, one bed being hori¬ zontal and over 37 ft. thick. The term “plaster of Paris” was mainly applied to it because gypsum is found in large quantities in the tertiary deposits of the Paris basin. Another reason is that lime and hair mortar is seldom used in Paris for plaster work, plaster of Paris being used for most kinds of internal and external work. Plaster is known in the color trade as terra alba. Plaster of Paris was known in England by the same name as early as the beginning of the thirteenth century. The gypsum, in blocks, was taken from France, and burnt and ground there. It continued to be burnt and ground by the users until the middle of the nineteenth century. The burning was done in small ovens, and the grinding in a mill, sometimes worked by horse-power, or more often by hand. Plaster is the most vigorous as it is the oldest vehicle for carrying down generation after generation the mas¬ terpieces of art with which the golden age of sculpture enriched the human race. For reproductive uses, plas¬ ter enables youth to contemplate antiquity in its noblest achievements. Today plaster is revolutionizing indus¬ trial art for us, and in all probability for those who are to come after us. Plaster, lowly and cheap, but docile and durable, is the connecting agent with this greatest of men’s endorsement in the past. Plaster thus employed in duplicating works of marble, pottery, and metal work, is today extending the finest indus- 62 CEMENTS AND CONCRETES tries, modern and ancient. Plaster is one of the best known fire-resisting materials for building purposes. After the conflagration at Paris, it was found the beams and columns of wood which had been plastered were entirely protected from fire. In cases where limestone walls had been ruined on the outside by the flames pass¬ ing through the window openings, the same walls in¬ ternally escaped almost unscathed owing to their being protected with plaster. Plaster in some climates has great lasting properties. The Egyptians covered their granite sometimes, and sand stone always, with a thin coating of stucco. The Greeks coated even their mar¬ ble temples with plaster, and the plaster portions are now in better preservation than unprotected masonry, particularly at Agrigentum in Sicily. Quick and Slow Setting Plaster. —M. Landrin, in giv¬ ing the results of his long continued studies relative to the different qualities of gypsum, states that the more or less rapid setting of plaster is due to the mode in which it is burned. Its properties are very different • when prepared in lumps or in powder. The former when mixed in its own weight of water sets in five min¬ utes, while the latter under similar conditions takes fif¬ teen minutes. The reason probably is that plaster in powder is more uniformly burned than when it is in lumps, which tends to prove this fact, that when the latter is exposed longer than usual to the action of heat it sets more slowly. Gypsum prepared at a high tem¬ perature loses more and more of its affinity for water, retaining, hovrever, its property of absorbing its water of crystallization. Plaster heated to redness and mixed in the ordinary manner will no longer set; but if, in¬ stead of applying a large quantity of water, the small¬ est possible portion is used (say one-third of its PLASTER, LIME, ETC. 63 weight), it will set in ten or twelve hours, and becomes extremely hard. To prepare good plaster / it should not be burned too quick to drive off all its moisture, and for its molecules to lose a part of their affinity for the water. If the plaster is exposed to heat until it has only lost 7 or 8 per cent, of its moisture it is useless, as it sets almost immediately. If, however, the burning is again resumed, the substance soon loses its moisture, and if then exposed to the air it very rapidly retakes its water of crystallization, and absorption continues more slowly. It then sets slowly, but attains great hardness. Testing .—The quality of plaster may be tested by simply squeezing it with the hand. If it cohere slight¬ ly, and keeps in position after the hand has been gently opened, it is good; but if it falls to pieces immediately it has been injured by damp. Although plaster does not chemically combine with more than one-fourth of its weight of water, yet it is capable of forming a much larger quantity into a solid mass, the particles of plas¬ ter being converted into a network of crystals, mechan¬ ically enclosing the remainder of the water. Sulphate of lime (plaster) is soluble in water to the extent of 1 part in about 450, the solubility being but little influ¬ enced by temperature. It is on account of this solu¬ bility in water that cements which have to a large ex¬ tent plaster for their bases are incapable in this raw state of bearing exposure to the weather. The setting of plaster is due to hydration, or its having but little water to take up to resume a state of consolidation. Plaster is used with hydraulic limes to stop the slaking, and convert the lime into cement. These are then called “selenitic.” In 100 parts of gypsum there are 46 acid, lime 32, 64 CEMENTS AND CONCRETES and water 22 parts. Good plaster should not begin to set too soon, and it should remain for a considerable time in a creamy state. When once set it should be very hard. Plaster should set slowly, as it gives more time for manipulation, but principally because one which sets quickly and swells never becomes, so hard as slow-setting material. The quality of plaster can¬ not be determined by its color, the color being regu¬ lated by that of the gypsum • but all things being equal, the whitest and hardest generally yields the best plas¬ ter. But as the exception proves the rule, it may be mentioned that some plasters (such as Howe’s) are of a delicate pink tint, and of a very fine grain, and ex¬ ceedingly strong when gauged. This pink plaster is much appreciated by many plasterers for making origi¬ nals, as owing to its fineness and density it is very suit¬ able for cleaning or chasing up models taken from the clay, and also for durable moulding pieces. One of the whitest plasters known, which is also very close in tex¬ ture, is that manufactured by Cafferata. For cast work the color of plaster is of small moment, because the cast work is sooner or later colored with paint, and more¬ over, unfortunately daubed over with distemper, or worse still, with whitewash. Coarse plasters are darker in color than fine. Coarse plasters of a sandy nature, and which rapidly sink to the bottom when put in water, contain too much silica, or improperly burnt gypsum, or are derived from a bastard gypsum, and are generally of a weak nature. Compressive and Adhesive Strength .—The compres¬ sive resistance of properly baked plaster is about 120 lbs. to the square inch when gauged with neat water and 160 lbs. when gauged with lime water; thus show¬ ing that lime water hardens and improves the affinity PLASTER, LIME, ETC. 65 of plaster. The adherence of plaster to itself is greater than to stone or brick. The adhesion to iron is from 24 to 37 lbs. the square inch. French Plaster .—A considerable quantity of French plaster was formerly used in this country but our own is more uniform in quality and cheaper in price, so the use of the French material is somewhat limited. In Paris various kinds of gypsum mortars are in general use, raw gypsum and other materials being often inter¬ mixed. They also contain free carbonate of lime, ac¬ cording to the degree of heat to which the raw stone has been subjected. The Hotel de Platres, in Paris, affords a good illustration of the constructive uses to which plaster can be put, some of the blocks being about a hundred years old. Limes .—Lime is one of the most important materials in the building trades. Limestone is the general term by which all rocks are roughly classified which have carbonate of lime for their basis. They are obtained from many geological formations, varying in quality and chemical properties. The carboniferous consists of nearly pure carbonate of lime. In the limestone of the lias carbonate of lime is associated with silica and alumina (common clay), in proportions varying from 10 to 20 per cent. Carbonate of lime is found in a state of chemical purity in rhombohedral crystals as Iceland spar. It is also found in six-sided prisms, known to mineralogists as arragonite. Its purest form as a rock is that of white marble. Colored marbles contain iron, manganese, etc. The lias strata consists of a thin layer of hard lime¬ stone separated by another of a more argillaceous char¬ acter, or shale, containing various proportions of car¬ bonate of lime. 66 CEMENTS AND CONCRETES Hydraulic Limes .—Hydraulic limes are those which have the property of setting under water or in damp places, where they increase in hardness and insolubil¬ ity. The blue lias lime formation is that from which hydraulic lime is principally made. This lime, while it has excellent hydraulic properties, can hardly be classed as a cement. The stones which produce these limes con¬ tain carbonate of lime, clay, and carbonate of mag¬ nesia. The clay plays an important part in giving hy- draulicity to the lime, consequently this power is great¬ er in proportion to the amount of clay contained in the lime. The proportion of clay varies from 10 to 30 per cent. When lime contains clay it is not so easily slaked as pure lime, and does not expand so much in doing so, and therefore does not shrink so much in setting. Lias lime (called blue lias from the color of the stone from which it is produced) is very variable in quality and is generally of a feeble nature, but is sometimes of an hydraulic nature. M. Yicat divides them into three classes: feebly hydraulic, ordinary hydraulic, and emi¬ nently hydraulic. ‘‘Those belonging to the first class contain from 5 to 12 per cent, of clay. The slaking action is accompanied by cracking and heat. They also expand considerably, and greatly resemble the fat limes during this process. They are generally of a buff color. Those of the second class contain from 15 to 20 per cent, of clay. They slake very sluggishly in an hour or so without much cracking or heat, and expand very little. They set firmly in a week. The eminently hy¬ draulic limes contain from 20 to 30 per cent, of clay, are very difficult to slake, and only do so after a long time. Very frequently they do not slake at all, being reduced to a powder by grinding. They set firmly in a few hours, and are very hard in a month.” PLASTER, LIME, ETC. 67 A natural hydraulic lime is obtained from what ap¬ pears to be a sedimentary limestone that has been formed by being deposited from water which held it in solution. It is very fine-grained, and contains almost no fossils, and scarcely the trace of a shell is to be seen, except at the top and bottoms of the divisions, which are four in number, and in all from 9 to 12 ft. thick. When first worked, the stone was slaked in hot kilns, but now this is effected by grinding. According to the “M’Ara” process, the “lime shells” from the kiln are ground in the same way as the clinker of Portland ce¬ ment. Beginning with a stone-breaker, the lime passes from this to a pair of chilled crushing rollers, and final¬ ly to the millstones, after which the powder is carried by sere v-conveyor and elevator to a rotary screen, 12 ft. by 4 feet, covered with wire cloth, which retains and returns to the millstones any residue in excess of the required fineness. Sifting is a very important factor in the process, as it is scarcely possible to have the mill¬ stones so perfect that they will not pass a few large particles. The residue of imperfectly ground lime will doubt¬ less slake when mixed with water, but at long or un¬ certain periods, so that it is obvious that fine grinding is a necessity, and the setting properties are not fully and safely developed unless the whole is finely pulver¬ ized. With regard to “Fat lime”: the general prac¬ tice is for lime producers to show their lime as rich as possible by analysis, and for users to prefer a rich lime, for the reason that it makes a more plastic and better working mortar with the usual quantity of sand. Now, it has been proved by experiments, many and varied, and extending over a long period, by the most eminent authorities, French, German, English and American, 68 CEMENTS AND CONCRETES that this preference should exactly be reversed, and that the poorer common limes will make the best mor¬ tar, and will, in a comparatively short time, show some light setting power, whereas the very rich limes never take band, except in so far as they return to their orig¬ inal condition of carbonate by the reabsorption of car¬ bonic acid from the atmosphere, and by the slow evap¬ oration of the water of mixture. If it does not evapo¬ rate, the mortar remains always soft. If it evaporates too quickly, the mortar falls to powder, a result which must be in every one’s experience who has witnessed the taking down of old buildings, and the clouds of dust created by the removal of every stone. Some of the stones from which fat lime is produced contain a portion of sand as an impurity. They there¬ fore yield an inferior substance. This, though cheaper, is not so economical as pure lime, as it does not increase its volume so much when slaked. The pure or fat lime should only be used for plastering, as it is easily slaked, and therefore not so liable to blister as most hydraulic limes. It expands to double its bulk when slaked, and can be left and reworked again and again without in¬ juring it. The Romans are said to have prepared their limes. This “lime putty,” prepared by immersion for a longer or shorter period—seldom less than three weeks—before being used, is laid on in a very thin coat, and gives a hard skin to the surface. This hardness is largely, if not wholly, due to the fact that the lime is laid on in a thin layer on the floating coat that has already ab¬ sorbed carbonic acid from the air. This thin layer be¬ comes harder than the main body of the plaster. The whole process of preparing lime and laying J on the walls in thin coats, with a considerable space 01 PLASTER, LIME, ETC. 69 time between the coating, is conducive to the ultimate hardness of the whole. The lime is first slaked, and then made into coarse stuff, and setting stuff, all this t ; me being exposed to the carbonic acid of the atmos¬ phere. Again, each coat is long exposed to the same influence before being covered with the next, although in marked contrast to the system of using the mortar in building. Calcination .—The process of “lime burning” is car¬ ried out in several different ways. But whether the operation be carried out in the simplest manner, or in kilns constructed on the most scientific principles, it will still depend (both as regards the quality and quan¬ tity of lime produced) upon the kilnsman, as it is only by constant observation from day to day that the man becomes capable of judging whether the proper tem¬ perature has been reached or that a correct opinion can be formed as to the effects produced by the various disturbing causes which exert an important influence upon the working of a kiln, such as its size, shape, the quality of the fuel, and the state of the atmosphere. The kilns vary in size and shape in different districts, though they are generally inverted cones or ellipsoids, into which layers of limestone and fuel are alternately thrown. When worked continuously as running kilns, the lime is periodically .withdrawn from below, fresh quantities of fuel and stone being filled in at the top. When lime has not been properly calcined, or “dead burnt,” it will not slake with water. This may arise from two causes—from insufficient burning, when the limestone, instead of being entirely caustified, has only been changed into a basic carbonate, consisting of two equivalents of lime and one of carbonic acid, one-half only of its carbonic acid having been expelled. This CEMENTS AND CONCRETES 70 basic carbonate, on the addition of water, instead of forming a hydrate of lime, and being converted into a fine and impalpable powder, attended with the pro¬ duction of a large amount of heat, is changed, with little elevation of temperature, into a mixture of hy¬ drate and carbonate. In the case of hydraulic limes which contain a considerable amount of silica, this “dead burning” may arise from the limestone having been subjected to a too high temperature, whereby a partial fusion of the silicate of lime formed has been produced, giving an impervious coating to the inner portions of the stone, retarding the further evolution of the carbonic acid. On this account the eminently hydraulic limes require to be carefully calcined at as low a temperature as practicable; and hence it is not infrequently found that lias lime has been imperfectly calcined. Pure limes, if subjected to an excessive temperature, exhibit somewhat less tendency to com¬ bine with water than is the case with lime properly calcined. Caustic limes unite with water with great energy, so much so as to evolve a very considerable amount of heat. When water is poured upon a piece of well-burnt lime heat is rapidly generated, and the lime breaks up with a hissing, crackling noise, the whole mass being converted in a short time into a soft, impalpable powder, known as “slaked lime.” Slaking .—Chemically speaking slaked lime is hydrate of lime—that is, lime chemically combined with a definite amount of water. In the process termed “slak¬ ing” one equivalent or combining proportion of lime unites with one equivalent of water, or in actual weight 28 lbs. of lime combines with 91 lbs. of water (being nearly in the proportion of three to one) to form 37 lbs. of solid hydrate of lime. The water loses its liquid PLASTER, LIME, ETC. 71 condition, and it is to this solidification of water that the heat developed during the process of slaking is partly due. Slaking is a most important part in the process of making coarse stuff and putty lime. Unless the slak¬ ing is carefully and thoroughly done, the resultant ma¬ terials are liable to “blister’' or “blow,” owing to small particles still remaining in a caustic state. Blis¬ ters may not show until a considerable time has elapsed. There are three methods of slaking “lump- lime”—the first by immersion; the second by sprink¬ ling with water; and the third by allowing the lime to slake by absorbing the moisture of the atmosphere. Rich limes are capable of being slaked by immersion, and kept in a plastic state. They gain in strength by being kept under cover or water. Pliny states that the Romans had such great faith in this method that the ancient laws forbade the use of lime unless it had been kept for three years. All rich limes may be slaked by mixing with a sufficient quantity of water, so as to reduce the whole to a thick paste. Lump lime should first be broken into small pieces, placed in layers of about six inches thick, and uniformly sprinkled with water through a pipe having a rose on one end, or by means of a large watering-can having also a rose, and covered quickly with sand. It should be left in this state for at least twenty-four hours before being turned over and passed through a riddle. The layer of sand retains the heat developed, and enables the process of slaking to be carried out slowly throughout the mass. Any unslaked lumps may be put into the middle of the next heap to be slaked. The quantity of water should be perfectly regulated, as if over-watered a useless paste is formed. If a sufficient quantity is not supplied, a 72 cements and concretes dangerous powdering lime is produced. Slaking by sprinkling and covering the lime lumps is frequently done in a very imperfect and partial manner, and por¬ tions of the lime continue to slake long after the mortar has been used. Special care must be exercised, and sufficient time must be allowed for the lime to slake when this method is employed. Different qualities of lime require variable amounts of water; but the medium quantity is about a gallon and a half to every bushel of lime. No water should be added or the mass disturbed after slaking has be¬ gun. In most places the lime for making coarse stuff is generally slaked by immersion, and is run into a pit, the sides of which are usually made up with boards, brick work, or sand, the lime being put into a large tub containing water. When the lime is slaked, it is lifted out by means of a pail, and poured through a coarse sieve. It is sometimes made in a large oblong box, having a movable or sliding grating at one end to allow the lime to run out and also to prevent the sedi¬ ment from passing through. In preparing lime for plaster work, the general prac¬ tice is to slake it for three weeks before using. Not only so, but a particular cool lime is selected, for the reason that it is not liable to blister and deface the internal walls when finished. Now, while all this pre¬ caution is taken in regard to plastering, in making mor¬ tar for building the lime is slaked and made up at once, and it is frequently used within a day or two. But this is not all. Limes which are unsuitable for plaster work, known as hot limes, and which, when plasterers are obliged to usei must be slaked for a period of—not three weeks, but more—nearly three months before using, and are then not quite safe from PLASTER, LIME, ETC. 73 blistering, are the limes mostly used for building pur¬ poses. It will at once be seen that when mortars of these limes are used immediately, the unslaked par¬ ticles go on slaking for a long time, drying up the moisture, and leaving only a friable dust in the joints. This should help in understanding the old Roman law which enacted that lime should be slaked for three years before using. If three years should seem to us an absurd time, yet it may be justly said that at least three months are required to slake completely, and to develop fully the qualities of many of the common limes in everyday use. Major-General Gillmore, the eminent American specialist on the subject of Limes and Cement, mentions that in the south of Europe it is the custom to slake the lime the season before it is to be used. Mortar .—This is a term used for various admixtures of lime or cement, with or without sand. For plaster work it is usually composed of slaked lime, fnixed with sand and hair, and is termed “coarse stuff,” and some¬ times “lime and hair,” also “lime.” In Scotland the coarse stuff is generally obtained by slaking the lump lime (locally termed shells) with a combination of water sprinkling and absorption. The lime is placed in a ring of sand, in the proportion of one of lime to three of sand, and water is then thrown on in suffi¬ cient quantities to slake the greater portion. The whole is then covered up with the sand, and allowed to stand for a day; then turned over, and allowed to stand for another day; afterwards it is put through a riddle to free it from lumps, and allowed to stand for six weeks (sometimes more) to further slake by absorption. It is next “soured”—that is, mixed with hair ready for use. Sometimes when soured the stuff is made up in 74 CEMENTS AND CONCRETES a large heap, and worked up again as required for use. This method makes a sound, reliable mortar. In some parts lime slaked as above is mixed with an equal part of run lime. This latter method makes the coarse stuff “fatter” and works freer. All slaked limes have a greater affinity for water than the mechanically ground limes. Grinding is another process for making mortar or “lime,” and if made with any kind of limestone is beneficial. It thoroughly mixes the material, increases the adhesion, adds to the density, and prevents blister¬ ing. When there is a mortar-mill, either ground or lump lime can be used, and the coarse stuff may be made in the proportion of 1 part lime and 3 parts sand. The lime should be left in the mill until thor¬ oughly reduced and incorporated, but excessive grind¬ ing is detrimental. The process should not be con¬ tinued more than thirty minutes. Both material and strength is economized if lump lime is slaked before being put in the mill. When a mortar-mill is used for grinding the lime, the sand may be partly or wholly dispensed with, and excellent results are obtained by using old broken bricks (clean and well burnt), stone chippings, furnace cin¬ ders (free from coal), or slag. It is most essential in all cases that the materials used should be perfectly clean. It should be Rome in mind that a complete in¬ corporation of the ingredients is essential in the slak¬ ing and mixing for coarse stuff, whether done by hand or machine. The sand or other material used can be tested by washing a portion in a basin of clean water, then sifting through a fine sieve. If there is an undue residue of clay, fine dust or mud in the water or sieve, the whole of the aggregate should be washed or re- PLASTER, LIME, ETC. 75 jected. Lias lime should be mixed dry with sand and damped down for seven or ten days to ensure slaking. It should not be used fresh for floating or rendering. Pure or rich limes are not so well adapted for outside work, or places exposed to the action of damp, as hy¬ draulic limes. Mortar should be well tempered before using. Pliny states that it was an ancient practice to beat the mortar for a long time wfith a heavy pestle just before being used, the effect of which wmuld be not only more thoroughly to mix the materials, but to take from the outside of the sand the compound of lime and silica (if such had been formed during the period of seasoning) and by incorporating it with the mass, dispose it more rapidly to consolidate. Smeaton found that well-beaten mortar set sooner and became harder than mortar made in the usual way. Mortar made from hydraulic limes should be mixed as rapidly as is compatible with the thorough incorporation of the materials, and used as soon as practicable after mixing, because if put aside for any length of time its setting properties will deteriorate. Pure limes may be rendered hydraulic by mixing them with calcareous clays or shales, which have been so altered by the agency of heat that the silica they con¬ tain has to some extent assumed the nature of soluble silica. In good coarse stuff each granule of sand is coated over with the lime-paste so as to fill the inter¬ stices; the lime-paster is to hold the granular sub¬ stances in a concrete form. If too much lime-plaster is present, it is called “too fat”; if the lime-paster is deficient it is “too lean” or “poor.” This can be tested by taking up a portion on a trowel; the “fat” will cling to the trow r el while the “lean” will run off like wet sand. The coarse stuff can be tested by mak- 76 CEMENTS AND CONCRETES ing briquettes and slowly drying; the good will stand a great pressure, whereas the bad will not—in some cases falling to pieces. Some coarse stuff will appear “fat” on the trowel, but it may be the fatness of mud, not the fatness of lime, because sometimes sand is adulterated with fine-screened earth. When this stuff is made in the form of briquettes and dried, it will be extremely friable and easy to crush; or if put into water until soft, the earthy matter can be seen. Fine- screened earth, when dry and in bulk, does not seem an objectionable material; but in a wet state it is dirt or mud, and should at once be sent off to the works. All limes increase in strength by the addition of sand, being the reverse of Portland cement, which is weak¬ ened by this addition. Mr. Read made four samples of mortar with the proportions of ground lime and sand as follows: ‘ ‘ Ground lime mixed with 4, 6, 8 and 10 parts of clean washed sand to 1 part of ground lime respectively. All set and went hard. One of each was placed in water; that made with 4 parts of sand expanded and went to pieces; those with 6, 8 and 10 parts of sand remained whole, and continued to get harder.” The addition of a small proportion of brick dust to mortar will harden and prevent the disinte¬ gration of mortar. The proportions are 1 part of hrick dust, 2 parts of sand and 1 part of lime, mixed dry and tempered in the usual way. Adhesive Strength .—'The adhesive strength of mortar varies according to the amount of sand used. The more sand used in the mortar, the less its adhesion. The following table shows the force required to tear apart bricks bedded in mortar made with the usual proportions of sand at the end of twenty-eight days: PLASTER, LIME, ETC. 77 Adhesive Strengths of Limes and Cements. Fat lime and sand (1 to 3) 4% lbs. per Sq. In. Common lias lime and sand < < q a tt a a it a tt a a (1 to 4) 6% “ “ “ “ Portland cement (1 to 4) Og << << << << a a a a (1 to 6) 15% “ “ “ “ The old mortar which was held in such high esteem- by the Romans is said to have consisted of lime mixed with puzzolana or trass. Trass is a material similar in its nature to puzzolana, obtained from extinct vol¬ canoes in the valley of the Rhine, also in Holland, and is largely employed in engineering works. The name trass is derived from a Dutch word meaning a binding substance. Much lias been wwitten and said about the ancient and the old Roman mortars, but it may be safely said that, from the year one up to the present time, no cement or mortar has the strength, or could excel, or stand our variable climate as well as Portland cement. The primary cause of the premature decay which takes place in stuccos and cements, when used externally as a coating to walls, is the presence of muddy earth and decayed animal and vegetable matter in the sand used in the lime and cement. To this may be added the frequent impurities in the limes and ce¬ ment themselves. The impurities in the sand may be eradicated by a thorough washing, and the lime should be carefully selected, prepared and manipulated. Hav¬ ing now briefly reviewed the principal parts and process of mortar, the practical conclusions to be drawn are, that the quality of the lime is of as great importance as the quantity, and thorough slaking is imperative; that the proportions of sand may vary con- 78 CEMENTS AND CONCRETES siderably, and that it should be coarse and irregular in size, and of a clean and hard nature. The Hardening of Mortar .—According to the results obtained from tests and experience, the hardening of mortar is due to several causes acting collectively. These causes appear to be absorption of carbonic acid from the atmosphere, and the combination of part of the water with the lime which act upon the sand, dis¬ solve and unite with some of the silica of the sand is composed, thus forming a calcium silicate (silicate of lime). Some authorities state that the silicate of lime is formed by the reaction of lime and silicate of mor¬ tar, and to this is due the hardness of old mortar. In mortar from the pure lime, the initial setting is due to the evaporation of water, and to the production of minute crystals of hydrate of lime, which slowly ab¬ sorbs carbonic gas from the air, the rapidity of this absorption necessarily decreasing in proportion to the difficulties presented to the free access of air. The setting and hardening of hydraulic limes are due mainly to crystallization brought by the action of water on the silicate of lime and not mere absorption of carbonic gas from the atmosphere, as is the case of fat limes. The Romans were convinced that it was owing to prolonged and thorough slaking that their works be¬ came so hard, and were not defaced by cracks. Al¬ berti mentions that he once discovered in an old trough some lime which had been left there five hundred years, as he was led to believe by many indications around it, and that the lime was as soft and as fit to be used as if it had been recently made. Common mor¬ tar made of rich lime hardens very slowly, and only by the evaporation of the water of the mixture, and by the absorption of carbonic acid from the atmosphere, PLASTER, LIME, ETC. 79 with which it forms a crystalline carbonate of lime. This process, however, is so slow, that it gave rise to the French proverb that “Lime at a hundred years old is still a baby”; and there is a similar proverb among Scotch masons, “When a hundred years are past and gane, then gude mortar turns into stane. ” Mortar from the interior of the pyramids, where it has been ex¬ posed to the action of the air, still contains free lime, although it is five thousand years old. It has been ascertained that in rich lime mortars the carbonic acid penetrates about one-tenth of an inch into the joint in the first year, forming a skin or film which opposes the further absorption of carbonic acid, except at a decreas¬ ing ratio, so that the lime remains soft for an indefi¬ nite period. In illustration of this several cases have been cited, amongst others one by General Treussart, who, in the year 1822, had occasion to remove one of the bastions erected by Vauban in 1666. After these 156 years the lime in the interior was found to be quite soft. Dr. John, of Berlin, mentions that in removing a pillar of 9 ft. diameter in the Church of Saint Peter, Berlin, eighty years after erection, the mortar was found to be quite soft in the interior. General Pasley mentions several instances at Dover Harbor, and at Chatham dock yard, the latter in par¬ ticular, when part of the old wall was pulled down in the winter of 1834. The workmen were obliged to blast the brickwork fronting the river, which had been built with Roman cement, but the backing, done with common lime mortar, was in a state of pulp; the lime used had been prepared from pure limestone or chalk. But it is unnecessary to go back so far for knowledge of the absence of the setting quality in the rich limes, as there have been frequent experiences of it in the pres- 80 CEMENTS AND CONCRETES ent age. While these remarks are true of the richer limes, many of our limes are comparatively poor in carbonate, and associated with silica, alumina, mag¬ nesia and oxide of iron, which may either be partially combined in the natural state, or enter into combina¬ tion with the lime during the process of calcination, and these limes might be termed slightly hydraulic. M. Landrin, who submitted to the French Academy the results of some experiments on the liydraulicity and hardening of cements and lime, came to the conclusion that (1) silicates of lime raised to high temperature set with difficulty, and in any case, do not harden in water; (2) for the recalcination of cements to exert a maximum influence on the setting, in connection with water of the compound obtained, the process must be carried sufficiently far for the limes to act on the silica so as to transform it into hydraulic, and not fused silica; and (3) carbonic acid is an indispensable factor in the setting of siliceous cements, in as much as it is this substance which ultimately brings about their hard¬ ening. The comparative strengths of various mortars are shown in the following table: Comparative Strength of Grey Lime and Portland Cement Mortar, also Portland Cement Mortar with the addition of Lime and Mortar. —Redgrave. PLASTER, LIME, ETC. 81 X W t - D UVo a G .s » aj.y o3 a £ 4> =>•* w £- tj X MH 2” n o 3b o\2 S S3 “ O », r* «®8g O^ifl 'z, © a) * H o £ (U 4) * a cd •3 a cd c n to 0 ^ a a •d •M ' a o £ *> .a 0) • m &. U c/i 3 n S Vh o ° a ca 4> cd +-» 0) o x\ -M U O h-» •rH o o o • +J +J *J 'OIOtJI ' t- oo qo o' o © o o o o o o +J 4J +J -4-> *J +J H o o o o ®00 030®H d ■ i d ■ CO 05 H O t-' £-’ Cl cd CO OOtOi"jli( t* 00 T-H Tfl O CO co' oo’ o’ co' oo’ Cl OOOMO^ CD t- o o H CD CD O eoooOiHffit' M5 00 XI CO CD d co -h* ei id ci id CO ID T-H CO CO OS d r-l t-H t—( i—( o o o H-> H-> H-> OOION ID IC5 lO o’ o’ o’ o o o H-J *J *J H# Ttf £- CD O C- tH t-h O O CO CD 00 T* CO o’ 00 00 * CD CO Cl O 00 o I ‘ oo ■ I lO CD CD ^ CO 00 CD Water. 1.38 1.33 1.33 OCDOOOO dceoiooo 7—1 7—1 d 7—1 d d O CO o O CO o H H Cl a3 o o O • • • O CO CO 0 o CD CO a o o o . . . io co oo ca io co oo o B 3 t-H tH t-H • • • o o’ o’ 3 o‘c5© o cu a o o o o o o o o o o a , . o o o o o o o o o £ 0) O • • • HrHHHH t-H rH i-H rH o o o o o o o o o o o o c o o o o o o o o o o o o cd CQ d d’ d CO 00 O CO 00 o H rH CD 00 O rH f- fc- t-h d lOQlOO^O t-h d CO £- t- 00 t-H IO 05 d d 1-1 7-i d co i-i d co n d co l d CO 82- CEMENTS AND CONCRETES Magnesia in Mortars .—Magnesia plays an important part in the “setting” of hydraulic limes as well as in Portland cement. Vicat, after many experiments, was led to recommend magnesia as a suitable ingredient of mortars to be immersed in the sea, stating that if it could be obtained at a cost that would admit its appli¬ cation to such purposes, the problem of making con¬ crete unalterable by sea water would be solved. Gen¬ eral Gillmore, speaking of the American lime and ce¬ ment deposits, says: “Magnesia plays an important part in the ‘setting’ of mortars, derived from the ar- gillo-magnesian limestone such as those which furnish the Rosendale cements. The magnesia, like the lime, appears in the form of a carbonate. During calcination the carbonic acid is driven off, leaving protoxide of magnesia which comports itself like lime in the pres¬ ence of silica and alumina, by forming silicate of mag¬ nesia and aluminate of magnesia. These compounds become hydrated in the presence of water, and are pronounced by Vicat and Chatoney to furnish gangues, which resist the dissolving action of sea water better than the silicate and aluminate of lime. This statement is doubtless correct, for we know that all of these com¬ pounds, whether in air or water, absorb carbonic acid, and pass to the condition of subcarbonates, and that the carbonate of lime is more soluble in water holding carbonic acid and certain organic acids of the soil in solution than the carbonate of magnesia. At all events, whatever may be the cause of the superiority, it is pretty well established by experience that the cements derived from argillo-magnesian limestones furnish a durable cement for construction in the sea.” In Marshal Vaillant’s report to the French Academy of Sciences, from the Commission to which Chatoney PLASTER, LIME, ETC. 83 and Rivot’s paper was referred in 1856, this superiority of the magnesian hydrates is distinctly asserted. A few years ago the French Government Office of Civil En¬ gineers made a series of comparative tests on three sam¬ ples each of French, English and German cement, in which the results are given in favor of the German cement, which contains magnesia to the extent of 2.4 per cent, against 0.26 in the English and 0.32 in the French, and summed up thus: “A great value partly due to the higher percentage of magnesia contained in it.” Gillmore further says that magnesian limestone furnishes nearly all the hydraulic cement manufactured in the western part of the State of New York. At East Vienna it has been used for cement, and at Akron, Erie County, N. Y., a manufactory of some extent is in operation. Vicat says: “Having analyzed several old mortars, with the view of discovering, if possible, to what their superior durability might be attributed, I found, in some excellent specimens of very old mortar, magnesia to exist in considerable proportions.” The limestones, therefore, from which these mortars were prepared must have contained the silica and magnesia as constituent ingredients; and it is to be remembered that it is the presence of these substances which com¬ municates the property of hardening under water. Pro¬ fessor Scorgie says of carbonate of magnesia: ‘ ‘ Mag¬ nesium carbonate is a substance very similar to carbon¬ ate of lime; it loses its carbonic acid in burning, com¬ bines with silica, etc., and behaves generally in the same way; it does not slake, however, on being wetted, but combines with the water gradually and quietly sets to some extent in doing so. Magnesium carbonate com¬ bined with lime, reduces the energy of slaking, and in¬ creases that of the ‘setting’ process; when other sub- 84 CEMENTS AND CONCRETES stances are present, its behavior and combination with them are similar to those of lime. When carbonate of magnesia is present in sufficient quantity, say about 30 per cent., it renders lime hydraulic independently of and in the absence of clay.” Colonel Pasley also, by experiments, demonstrated that magnesium limestones are suitable for hydraulic mortars. The foregoing assertions that magnesium carbonate,, combined with lime, reduces the energy of slaking and increases that of the “setting” processes are satisfac¬ tory and conclusive. Many such evidences showing the value of magnesia in hydraulic mortars might be quoted, but perhaps these are sufficient. Effects of Salt and Frost in Mortar .—Few experi¬ ments have as yet been made to test the general effects of salt in mortars, though as a preventive of the effects of frost it has been tried with varying results. In some experiments, designed to ascertain the effect of frost upon hydraulic limes and cement gauged with and without addition of salt to the water, cubes of stone were joined together with cement mixed with water ranging from pure rainwater to water containing from 2 to 8 per cent, of salt. Before the cement was set the blocks were exposed in air at a temperature varying from 20 to 32 degrees Fahr., after which they were kept for seven days in a warm room. At the end of this time the samples were examined. The cement made with water was quite crumbled, and had lost all its tenacity. The cement made with water containing 2 per cent, was in better condition, but could not be described as good; while that containing 8 per cent, of salt had not suffered from its exposure to the lowest temperature available for the purpose of experiment. It is suggested as possible that the effect of the salt was merely to pre- PLASTER, LIME, ETC. 85 vent the water in which it was dissolved from freezing at the temperature named, and so permitted the cement to set in the ordinary way. But it must be allowed that in practice, salt dissolved in the water for mixing mortar has been successfully used to resist the effect of frost. A solution of salt applied to new plastered walls in the event of a sudden frost will protect the work from injury. The addition of a small portion of sugar will improve its adhesion, and increase the frost-resisting powers. Salt takes up the vapors from the atmosphere, caus¬ ing the work to show efflorescence, and in some instances to flake, especially in external work. That some en¬ gineers believe there is virtue in salt water is beyond doubt, because salt water has been named in their speci¬ fications for the gauging of concrete. Salt in Portland cement seems to act somewhat differently; as regards efflorescence it shows more in this material than in lime mortar. Salt should not be used in Portland cement work that has to be subsequently painted. According to the results of tests of mortar used for the exterior brick facing of the Forth Bridge piers below water they show a good average tensile strength. One part of Portland cement and one part of sand were slightly ground together in a mill with salt water, and briquettes made from this gauge gave an average of 365 lbs. per square inch at one week, and 510 lbs. at five weeks after gauging. It would be interesting to note the condition of this mortar a century hence, time being the trying test for all mortars. A solution of commercial glycerine mixed with the setting stuff, or used as a wash on newly finished lime plaster work, is a good preventive of the evil effects of frost. Glycerine solution may also be used for the same 86 CEMENTS AND CONCRETES purpose on new concrete paving. Strong sugar water mixed with coarse stuff has some power in resisting frost. The quantity depends upon the class of lime, but the average is about 8 lbs. of sugar to 1 cubic yard of coarse stuff or setting stuff. The sugar must be dis¬ solved in hot water and the stuff used as stiff as pos¬ sible. Sugar With Cement .—Sugar or other saccharine mat¬ ter mixed with cement has been tried with varying success. It is well known that saccharine is used with mortars in India. According to some experiments made in this country, the results obtained were that the addi¬ tion of sugar or molasses delayed the setting of the mortar, the retardation being greater when molasses was used. When certain proportions were not exceeded, the strength of the mixture was that of the pure cement. Less than 2 per cent, of sugar must be added to Port¬ land cement, and less than 1 per cent, to Roman, other¬ wise the mortar will not hold together. The sugar ap¬ pears to have no chemical action on the other materials, crystals of it being easily detected on the broken sur¬ faces, the increased binding power of the cement brought about by the addition of sugar being due more to mechanical than chemical causes. In my own experi¬ ments with sugar added to Portland cement for cast¬ ing deep undercut ornament figures and animals out of gelatine moulds, the results at first were very irregu¬ lar, some casts attaining great hardness, while others crumbled to pieces. The time of setting also varied considerably. Three different brands of cement were used, and it was found that the cement containing the most lime required more sugar than the lowest limed cement, but the average is about 1^2 P er cent, of added sugar. The sugar must be dissolved in the water used PLASTER, LIME, ETC. 87 for gauging. The setting and ultimate hardness is also influenced by the atmosphere. The casts should be kept in a dry place until set and dry, before exposing them to damp or wet. Portland cement has a tendency (es¬ pecially if over limed) to “fur” gelatine moulds, but the sugared cement leaves the moulds quite clean. In experiments by Austrian plasterers, mixtures of 1 part of cement and 3 parts sand, and 10 per cent, of water, and of pure cement with as much water as was necessary to give the mass plasticity, were prepared. From 1 to 5 per cent, of powdered sugar was well mixed with the dry cement. The cement used was of inferior quality, the sand being ordinary building sand, and not the so-called “normal” sand, which is of a superior quality. They were left to harden in a dry place, and not under water. For each series of samples made with sugar a comparative series without sugar was prepared, all the samples being made by the same man, under the same conditions and with the same care. The tenacity was ascertained by Kraft’s cement-testing machine. The strength was far below that prescribed and generally obtained. It should be mentioned that the samples with sugar (especially those of pure cement) showed a strong tendency during the first twenty-four hours to combine intimately with the smooth china plate on which they were placed to swell, and the results of the trial showed that with mixtures of cement and sand, and by harden¬ ing in a dry place, the binding effect may be increased by the addition of sugar, which reached its maximum with from 3 to 4 per cent, of sugar added. With pure cement the binding effect was not much increased. If the sugar used for gauging had been dissolved, and not mixed dry, the results would have proved better. 88 CEMENTS AND CONCRETES Sugar in Mortar .—Most writers have supposed that the “Old Roman Mortars” contained strong ale, wort, or other saccharine matter, and it is probable that the use of sugar with lime passed from India to Egypt and Rome, and that malt or other saccharine matter was used in their mortars. The addition of sugar to water enables it to take up about 14 times more lime than water by itself. The following is an extract from 'the Roorkee : “It is common in this country to mix a small quantity of the coarsest sugar, ‘goor,’ or ‘Jaghery,’ as it is termed in India, with the water used for mixing up mortar. Where fat limes alone can be produced their bad quali¬ ties may in some degree be corrected by it, as its influence is very great in the first solidification of mortar. This is attributed to the fact that mortars made of shell lime have stood the action of the weather for centuries owing to this mixture of Jaghery in their composition. Experi¬ ments were made on bricks joined together by mortar consisting of 1 part of common shell lime to 1 y 2 of sand, 1 lb. of Jaghery being mixed with each gallon of water. The bricks were left for 13 hours, and after that time the average breaking weight of the joints in 20 trails was 6i/ 2 lbs. per square inch. In twenty-one specimens joined with the same mortar, but without the Jaghery, the breaking weight was 4y 2 lbs. per square inch.” The Madras plasterers make most beautiful plaster work, almost like enamelled tiles, the shell lime being mixed with Jaghery. The surface takes a fine polish and is as hard as marble, but it requires a good deal of patient manipulation. Dr. Compton has made some ex¬ periments with sugar gauged with cements and mortars, and says, ‘ ‘ That in medicine there are two kinds of lime- water, one the common lime-water, that can be got by mixing lime and water, and it is particularly noted PLASTER, LIME, ETC. 89 that, add as much lime as you like, it is impossible to get water to dissolve more than half a grain of lime in one ounce, or about two teaspoonfuls of water. But by add¬ ing 2 parts of white sugar to 1 part of lime, there is a solution obtained which contains about times more lime in the same quantity of water. Here it is to be ob¬ served—and it is a most important point—that there are hot limes, such as Buxton, which if they be incautiously mixed with them, will burn the sugar, make it a deep brown color, and convert it into other chemical forms, and possibly destroy its value in mortar.” The Jaghery sugar used in India is sold in the London market at about a penny a pound. Treacle seems to be the most promising form of saccharine matter; beetroot sugar is not good for limes or cements. There is a rough unrefined treacle which is very cheap, and it is supposed would have an excellent effect. Herzfeld states that he used coarse stuff, consisting of 1 part of lime to 3 of sand, to which about 2 per cent, of sugar had been added, to plaster some walls in the new building of the Berlin Natural History Museum, and on the day following he found the lime plaster had hardened as if gauged with plaster. He also found it useful in joining .bricks, and recommends the coarse stuff to be fresh made, and not with a great proportion of water; and states that good molasses will yield as good results as sugar. . Lime Putty .—This material is prepared in a similar way to run lime intended for coarse stuff. It is run through a finer sieve into a box or pit. If the latter is used the interior should be plastered with coarse stuff to prevent leakage and keep the putty clean. For good work the best class of lump lime should be used. The putty should be allowed to stand for at least three 90 CEMENTS AND CONCRETES months before it is used. For common work the lump lime for making coarse stuff, putty and setting stuff is often run into one pit. The putty at the end farthest from the sieve, being the finest, is retained for putty and for making setting stuff, and the remainder, or coarser portion, being used for coarse stuff. In many instances the putty is left for months in an unprotected state dur¬ ing the progress of the building, which is wrong. It may be kept for an indefinite time without injury if protected from the atmosphere, and therefore it should be covered up to resist the action of the air, as it absorbs the car¬ bonic acid gas and thus becomes slightly carbonated and loses to a certain extent its causticity, and consequently its binding and hardening properties. Pliny states that the old Roman limes were kept in cov¬ ered pits. If a small portion is taken off the top of the putty it will be found not only dry, but scaly, short and inert; whereas a portion taken from the middle, or up to the part carbonated, will be found to be of an oily and tenacious nature. A cute plasterer always selects the putty furthest from the sieve for mitring purposes, as it is the finest. Setting Stuff .—This material is composed of lime putty and washed fine sharp sand. The proportion of sand varies according to the class of lime and kind of work, but the average is 3 parts of sand to 1 of putty. The various proportions are given where required for the different works. Setting stuff is used for finishing coat of lime plastering. It is generally made on a platform of scaffold boards, and sometimes in a bin. The putty and sand are thoroughly mixed together by aid of a larry. The sand should be sized by washing it through a sieve having a mesh of the desired size. In some districts it is made by pressing or beating the putty and sand PLASTER, LIME, ETC. 91 through a ‘ ‘ punching sieve ’ ’ into a tub. Setting stuff is less liable to shrink and crack, and is improved generally if it is allowed to stand after being made until nearly hard, but not dry, and then “knocked up” to the re¬ quired consistency with water (preferably lime-water) and the aid of a shovel and larry. While the stuff is firming by evaporation it should be covered up to protect it from dust and atmospheric influences. It should be used as soon as “knocked up.” Setting stuff may be colored to any desired tint, and also mixed with various ingredients to obtain a brilliant and marble-like surface. Haired Putty Setting .—Haired putty was formerly used to a very considerable extent as a setting coat in districts where the local lime was of a strong or hydraulic nature, not very readily manipulated when mixed with sand, as used for setting stuff. This material is com¬ posed of fine lime putty and well-beaten white hair. The hair was thoroughly mixed with the putty to toughen and prevent it from cracking. To such an extent was hair added that in some instances the setting coat when broken had the appearance of white felt. This class of setting stuff is now seldom used. Lime Water .—This water has many medicinal virtues, and is a simple and inexpensive remedy for cuts and bruises. Plasterers are generally healthy and free from any infectious diseases. This may be partly owing to their almost constant contact with lime. Lime water, used as a wash, will harden plaster casts. It is also used when scouring and trowelling setting stuff to harden the surface. Hair .—Hair is used in coarse stuff as a binding me¬ dium, and gives more cohesion and tenacity. It is usu¬ ally ox-hair (sometimes adulterated with the short hair of horses). Good hair should be long, strong and free CEMENTS AND CONCRETES it’om grease or other impurities. It is generally obtained in a dry state in bags or bundles. This dry hair should be well beaten with two laths to break up the lumps, as, unless the lumps are thoroughly broken so as to sepa¬ rate the hair they are only a waste, and worse than no hair at all 2 since the lumps have no binding power and will cause a soft weak spot in the plaster when laid. Many failures of ceilings have been caused by the hair not being properly beaten and mixed. Human hair is sometimes used for jerry work. Goats’ hair is often used here. Hair is usually obtained direct from the tanners’ yard, fresh and in a wet state. This makes the best work, as it is much stronger and mixes freely. Hair should never be mixed with hot lime, and with no mor¬ tal’s until nearly ready for using, because wet or hot lime weakens the hair, more especially if dry. Coarse stuff for first coating on lath work requires more hair than for brick or stone work. When coarse stuff is made in a mill the hair should not be added until the stuff is ground, as excessive grinding injures it. Fibrous Substitutes for Hair .—Manila fiber as a sub¬ stitute for hair in plaster work has been the subject of experiments in this country. One of the most conclu¬ sive of these tests was made by four briquettes or plates of equal size, one containing manila hemp, a second sisal hemp, a third jute and a fourth goats’ hair of the best quality. The ends of the plates were supported and weights suspended from the middle. The result showed that plaster mixed with goats’ hair broke at 144% lbs. weight, the jute at 145 lbs., the sisal at 150, and the manila at 195, in the latter case the hemp not breaking, but cracking, and though cracked in the center, the lower half of this plate, when it was suspended, held onto the upper half, the manila securing it fast. The three other PLASTER, LIME, ETC. 93 plates were broken—that is, the two parts of each plate had severed entirely. Another experiment consisted in mixing two barrelfuls of mortar, each containing equal portions by measure of sharp sand and lime, one of the barrels, however, being mixed with a proper quantity by measure of manila hemp, cut in lengths of iy 2 to 2 inches, and the other of best goats ’ hair. On being thor¬ oughly mixed with the usual quantity of water, the re¬ spective compounds were put in the barrels and stored away in a dry cellar, remaining unopened for nine months. On examination the hair mortar crumbled and broke apart, very little of the hair being visible, showing that the hair had been consumed by the action of the lime; but the other, containing the hemp, showed great cohesion. It required quite an effort to pull it apart, the hemp fiber permeating the mass and showing little or no evidence of any injury done to it by the lime. Sawdust as a Substitute for Hair .—Sawdust has been used as a substitute for hair, also for sand in mortar for wall plastering. It makes a cheap additional ^aggregate for coarse stuff. Sawdust mortar stands the effects of rough weather and frost when used for external plaster¬ ing. The sawdust should be used dry and put through a coarse sieve to exclude large particles. I have used it with plaster for both run and cast work. It proved use¬ ful for breaks of heavy cornices by rendering the work strong and light for handling. Some kinds require soak¬ ing or washing, otherwise they are liable to stain the plaster. Several patents have been issued in America for the use of sawdust in place of hair and of sand. One of these is for the use of equal parts of plaster, or lime and sawdust; another is for the use of 4y 2 parts each slaked lime and sawdust to 1 part of plaster, part of glue and 1-16 part of glycerine, with a small part of hair. 94 CEMENTS AND CONCRETES Kahl’s patent plaster consists of 35 per cent, of saw¬ dust, 35 per cent, of sand, 10 per cent, of plaster, 10 per cent, of glue, and 10 per cent, of whiting. Sand .—Sand is the most widely distributed substance in nature, not only in the mineral but also in the animal and vegetable kingdoms. Clay contains no silica (the chemical name for sand). Sand is the siliceous particles of rocks containing quartz, production by the action of rain, wind, wave and frost. Some kinds of sand are also found inland; the deposits mark the sites of ancient beaches or river beds. Sand is classed under various heads, viz., calcareous, argillaceous and metallic. Sand varies in color according to the metallic oxides contained in them. Few substances are of more importance than sand for plastic purposes. Its quality is of primary im¬ portance for the production of good coarse stuff, set¬ ting stuff, and for gauging with Portland or other cements used for plaster work. Its function is to induce the mortar o»r cement to shrink uniformly during the process of setting, hardening or drying, irregular shrink¬ age being the general cause of cracking. Sand is also a factor in solidity and hardness; while being of itself cheaper and used in a larger proportion than lime or cement, it decreases the general cost of materials. There are three kinds—pit, river and sea sands. They gen¬ erally contain more or less impurities, such as loam, clay, earth and salts, necessitating their being well washed in water, more especially for the finishing coats of plaster or cement work. Pit sand is sometimes found quite clean; it is generally sharp and angular. River sand is fine grained, not so sharp as pit sand, but makes good setting stuff. Sea sand varies in sharpness and size, and for plastering it should be washed to free it from saline particles which cause efflorescence. PLASTER, LIME, ETC. 95 Regarding the use of sand in mortars, it may almost be spoken of as a necessary evil. Sand is necessary to give body and hardness to an otherwise too soft and plastic material, and the coarser and cleaner the better, as the coarse particles allow the carbonic acid to pene¬ trate further into the body of the mortar, and assist in the hardening process for this reason. In the case of cements of all kinds sand is only good for lessening the cost of the aggregate, and in the case of the majority of sands in daily use in most places the strength is reduced out of all proportion to the saving effected. Brunei, in the Thames Tunnel, was so convinced of this that he used pure Portland cement in the arches; and General Pas- ley, treating of this, recommends that only pure cement should be used on all arduous works. As to the quality of sands, they are of very wide variety—so much so, that 1 part of an inferior or soft clayey sand will reduce the strength of mortar as much as 3 or 4 parts of clean sharp granitic sand. This is well exemplified in the sand test, which is made with what is called standard sand, being a pure silecious sand sifted through a sieve of 400 holes to the square inch and re¬ tained on one of 900. Good sand for lime plaster should be hard, sharp, gritty and free from all organic matter. For coarse stuff and cement for floating coats it should not be too fine. Good sand for plaster work may be rubbed between the hands without soiling them. The presence of salt in sand and water is found not to impair the ultimate strength of most mortars; nevertheless it causes an efflorescence of white frothy blotches on plaster surfaces. It also ren¬ ders the mortar liable to retain moisture. Fine-grained sand is best for hydraulic lime; the coarse-grained is best for fat limes, and coarse stuffs and 96 CEMENTS AND CONCRETES Portland cements for floating. Sand should not be uni¬ form in size, but, like the aggregate for concrete, should vary in size and form. A composition of fine and coarse sand for coarse stuff, unless the sand is naturally so mixed, gives the best results, for as the lime will receive more sand in that way without losing its plasticity it will make a harder and stronger material, whether coarse stuff, setting stuff or for Portland cement work. If there is plenty of fine sand and a scarcity of coarse sand, they should be mixed in the proportion of 2 of coarse to 1 of fine. If on the other hand, there is plenty of coarse sand and a scarcity of fine, they should be mixed in the proportions of 2 of fine to 1 of coarse. The proportion of sand varies according to the different kinds and qualities of limes and cements, also purposes. Baryte is some¬ times used as a substitute for sand. Silver sand is used for Portland cement work when a light color and a fine texture is required. Mastic .—Mastic was formerly extensively used for various purposes in which now Portland cement is chiefly employed. It is still used sometimes for pointing the joint between the wood frames of windows and the stone work. Mastic is waterproof, heat-resisting and adheres to stone, brick, metal and glass with great tenacity. Mas¬ tic is made in various ways. Some plasterers make their own. Scotch Mastic is composed of 14 parts of white or yellow sandstone, 3 parts of whiting and 1 part of lith¬ arge. These are mixed on a hot plate to expel any mois¬ ture and then sifted to exclude any coarse particles. It is then gauged with raw and boiled linseed oil in the proportion of 2 of raw to 1 of boiled oil. The sandstone is pounded or ground to a fine powdered state before PLASTER, LIME, ETC. 97 being mixed. The surface to be covered is first brushed with ]inseed oil. Common Mastic is prepared as follows: 100 parts of ground stone, 50 parts silver sand or of fine river sand, and 15 parts of litharge. These are all dried and mixed and passed through a fine sieve; it then resembles fine sand. This mastic may be kept for any length of time in a dry place. When required for use it is gauged with raw and boiled linseed oil (in equal proportions) until of the consistency of fine stuff. It requires long and fre¬ quent beating and kneading—in fact, the more it is knocked up the better it works. Its fitness for use can be ascertained by smoothing a portion of the gauge'with a trowel. If there are any separate parts of the differ¬ ent materials or bright spots seen the knocking-up must be renewed until it is of even texture. The addition of 15 parts of red lead is sometimes used to increase the tenac¬ ity of the mastic. Mastic Manipulation .—The walls are prepared for mastic by raking out the joints and sweeping wfith a coarse broom, and the brick work well saturated with lin¬ seed oil. Narrow screeds about 1 inch wide are formed in plaster to act as guides for floating the work plumb and level. When laying the mastic it must be firmly pressed on and the floating rule carefully passed over the sur¬ face until it is straight and flush. The screeds are next cut out and the spaces filled in with extra stiff mastic. The whole surface is then finished with a beech or syca¬ more hand float, leaving a close and uniform texture. Mastic moldings are first roughed out with Medina or other quick-setting cement. The running mold is muffled so as to allow *4 inch for the mastic coat. Hamelein’s Mastic .—This mastic consists of sand and pulverized stone, china, pottery, shard, to which are 98 CEMENTS AND CONCRETES added different oxides of lead, as litharge, gray oxide and minium, all reduced to powder, to which again is added pulverized glass or flint stone, the whole being intimately incorporated with linseed oil. The propor¬ tions of the ingredients are as follows: To any given weight of sand or pulverized pottery ware add two-thirds of the weight of pulverized Portland, Bath or any other stone of the same nature. Then to every 550 lbs. of this mixture add 40 lbs. of litharge, 2 lbs. of pulverized glass or flint stones, 1 lb. of minium and 2 lbs. of gray oxide of lead. The whole must be thoroughly mixed together and sifted through a sieve, the fineness of which will de¬ pend on the different purposes for which the mastic is intended. The method of using is as follows: To every 30 lbs. of the mastic add 1 quart of linseed oil and well mix together either by treading or with a trowel. As it soon begins to set, no more should be mixed at a time than is requisite for present use. Walls or other sur¬ faces to be plastered with this material must first be brushed with linseed oil. Mastic Cement .—Mix 60 parts of slaked lime, 35 parts of fine sand and 3 parts of litharge, and knead them to a stiff mass with 7 to 10 parts of old linseed oil. The whole mass must be well beaten and incorporated until thoroughly plastic. This mastic cement assumes a fine smooth surface by troweling. It is impervious to damp and is not affected by atmospheric changes. TERMS AND PROCESSES. The following descriptions are suited to most locali¬ ties, though there are districts in the East and South that vary somewhat from the processes as described; the difference, however, is so trifling that the regular plasterer will have no trouble in reconciling such differ¬ ences. Tliree-Coat Work. i—Three-coat work is usually speci¬ fied by architects for all good buildings, but sometimes two-coat work is specified for inferior rooms, closets, at¬ tics or cellars in the same building. Three-coat work makes a straight, smooth, strong and sanitary surface for walls and ceilings when properly executed. The follow¬ ing is the process for three-coat work, which consists of first-coating, floating and setting. First-Coating. —“First-coating” is termed in the United States “scratch-coating.” It is executed by lay¬ ing and spreading a single coat of coarse stuff upon the walls and ceilings to form a foundation for the subse¬ quent floating and setting coats. Coarse stuff for first- coating should be uniformly mixed or “knocked up,” as commonly called. It should contain more hair than that used for floating, so as to obtain a strong binding key on the lath-work and form a firm foundation for the float¬ ing coat. Coarse stuff may be tested by lifting some from the heap on the point of a trowel. If it is suffi¬ ciently haired and properly mixed the stuff should cling to the trowel when held up and the hairs should not be more than 1-16 inch apart. It should be stiff enough to cling and hold up when laid, yet sufficiently soft and 99 100 CEMENTS AND CONCRETES plastic to go* through the interstices between the laths. Unless the stuff is made to the proper consistency it will “drop”—that is, small patches where the excess water accumulates or at weak or too wide spaced laths will fall soon after being laid. When first-coating ceilings, the coarse stuff should be laid diagonally across the laths, a trowelful partly over¬ lapping the previous one, the one binding the other. By laying the stuff diagonally the laths yield less, present a firmer surface and are not so springy as when laid across or at right angles to them. Laying the stuff diagonally and overlapping each trowelful helps to retain the stuff in its place, which otherwise is apt to “drop.” The stulf should be laid on with a full-sized laying trowel, using sufficient pressure to force it between the laths and to go sufficiently through to form a rivet and lap or clinch on the upper sides of the lathing. The stuff should be laid fair and as uniform in thickness as possible. The thickness should not exceed % inch or be less than % inch. If too thick it tends to weigh down the lath work and is apt to crack; if too thin the subsequent scratching is liable to cut the coat down or nearly to the laths, thus leaving a series of small detached pats which are un¬ stable and form a weak foundation for the floating coat and are a source of cracks and often the cause of the work falling when subjected to vibration. A thickness of y■*».. V : s \ - • * ’• -.-I- i-' ; — ? —-v* .- . ; 1 f lv.;/^Vt .... i. . : i.. * * t T .j tT"t' . « , ;m< vui5* t- t'.w'JU.viii'ti: .v.,»'I pint; IV 2 oz. black to 1 gill; y 2 gill black to 1 gill grey shade. Dark Verd Antique. —Green spots cut; grey spots cut; black spots with green and grey. Yeining 2y 2 oz. green to y 2 pint (rich mixing); 2y 2 oz. dark green to y 2 pint (rich mixing) ; 14 oz. black to y 2 pint (rich mixing). Plain mixing, same as above, with small alabaster spots, and small black spots. Black and Gold.— 5 oz. of black to 1 pint. Veining, 2 shades dark sienna to y 2 pint (rich mixing) ; 2 shades light to y 2 pint (rich mixing) ; 2 parts light and grey, with alabaster spots, and crumbs. Veining must be stiff; 3 oz. of black to 1 gill. Walnut. —2 parts burnt umber; 1 part rose pink. Verta Alps Marble. —5 oz. black to 1 pint. Veining, 1 y± oz. of green to 1 y> gills; I /4 oz. green to y 2 gill, with black crumbs chopped three times for the ground. Basse De La Vantz Marble. —Rich mixing with indi¬ go blue —1 shade light purple brown; 1 shade dark pur¬ ple brown; 1 shade Venetian red. Yeining, black for the ground, and white and green veining for the mixing, with alabaster spots and crumbs. MISCELLANEOUS MATTERS 275 Polishing White Scagliola .—White scagliola is often made with superfine Keen’s cement. A small portion of mineral green or ultramarine blue is added to improve and indurate the white color. White work requires spe¬ cial care to prevent discoloration or specks. When the work is left for drying purposes, or at the end of the day, it should be covered up with clean cotton cloths to pre¬ vent the ingress of dust, smoke or being touched with dirty hands. The tools should be bright and clean. Steel tools should be as sparingly used as possible. When the cement has thoroughly set and the work is hard, it is rubbed down with pumice-stone, or finely grained grit¬ stone, by the aid of a sponge and clean water, rubbing lightly and evenly until the surface is perfectly true. It is then stoned with snake-water (Water of Ayr), using the sponge freely and the water sparingly until all the scratches disappear. Afterwards well sponge the sur¬ face until free from glue and moisture. It is now ready for the first stopping. Stopping is an important part of the polishing process, and should be carefully and well done, to ensure a good, sound, and durable polish. First gauge a sufficient quantity of cement and clean water in a clean earthenware gauge-pot. The gauged stuff should be about the consistency of thick cream. It is well dubbed in, and brushed into and over the surface, taking care that no holes or blubs are left. When the stuff on the face gets a little stiff, scrape off the super¬ fluous stopping with a hard-wood scraper having a sharp edge. Then repeat the brushing (but not the dubbing) with the soft gauged stuff, and scraping two or three times, or until the surface is solid and sound. The work is now left until the cement is perfectly set. It is then stoned again for the third time with a piece of fine snake- stone, and stopped as before, with the exception that the 276 CEMENTS AND CONCRETES superfine stopping is not scraped off, but wiped off with soft clean rags. The work is left until the cement is set and the surface dry. It is then polished with putty powder (oxide of tin), which is rubbed over the surface with soft clean white rags, damped with clean water. In polishing mouldings, the stone must be cut or filed to fit each separate member of the moulding. Polishing Scagliola .—The polishing of scagliola is slightly different. It is rubbed down with a soft seconds (marble grit) or gritty stone, using the sponge and water freely until the surface is true. The glut and glue are cleaned off with a brush and sponge, using plenty of water, until the pores are free from grit. The moisture is sponged off, and the work left until sufficiently dry. It is then stopped in the same manner as white work, but using stiff stopping for large holes and steel scrapers in¬ stead of wood. The stopping is made with the same kind of plaster, size water, and color as was used for the ground color of the marble that is being imitated. The stopping and stoning is repeated as before, and it is finally polished with putty powder, using pure linseed oil instead of water. The repeated operations of stopping and stoning must not be proceeded with until the previous stopping is perfectly set, and the work dry. A small portion of spirits of turpentine is sometimes added to the gauged colored stuff to facilitate the drying. The work between each combined stopping and stoning will take from one to five days to dry, according to the size and thickness of the work and the state of the atmos¬ phere. Never dry the work by heat. The thorough dry¬ ness and hardness of the work are most essential be¬ fore proceeding to polish with the putty powder and lin¬ seed oil, because any contained damp will work out and spoil the polish. Work not perfectly dry may take a MISCELLANEOUS MATTERS 277 high polish, but it will soon go off when the damp comes through. Columns or large hollow work are not so liable to be affected by the damp, as it may escape through the back; but there must be some opening or ventilation to allow it to finally escape. If the polishing is well and carefully done, the polish produced on scagliola will equal, if not surpass, that on real marble. Tripoli polishing stone, sometimes called alana, is a kind of chalk of a yellowish-grey color. Water of Ayr stone is also used for polishing. In large work a rubber of felt dipped in putty powder may be used. Salad oil is sometimes used for finishing. Linseed oil makes the hardest finish, and dries quicker. Marezzo .—Marezzo artificial marble manufactured from plaster or Keen’s cement and mineral coloring mat¬ ter is made in wood or plaster moulds for moulded work, and on slate or glass benches if in slabs. If thick plate glass is used, the worker has the advantage of being able to look through it to see if the figure of the work re¬ quires altering. Glass also has the advantage of leaving a smoother and more polished face. All wood and plaster moulds should be got up with a good face, and properly seasoned, to save stoning and polishing the face of the work. Keen’s cement may be used advantageous¬ ly in making Marezzo, especially for chimney pieces, or other works required for exposed positions. Keen’s cement for Marezzo should be of the highest class. If the cement is not of the best, it will effloresce, rendering the work of polishing difficult, if not spoiling it alto¬ gether. Keen’s cement requires no size water, but in gauging either Keen’s or plaster, no more should be gauged than can be conveniently used. The quantities of colors, Keen’s cement, plaster, and size water should be measured and gauged pats kept for future reference. 278 CEMENTS AND CONCRETES All gauge-pots snould be of earthenware, as they are more easily cleaned out, and do not rust, as is the case with metal pots. All the tools should be kept bright and clean, as when working scagliola. Marezzo is made in the reverse way to scagliola, as the face or marble is put in the mould first, and the core or backing put on afterwards. All the mineral colors should be of good quality, in fine powder, and ground in water, known as “pulp.” A number of basins should be handy, and there should be a supply of twist silk in skeins varying in diameter from Va to X A of an inch, and cut into lengths of 14 to 18 inches. For common work, good long flax fibre may be used. Canvas is also required. One end of the silk or fibre skein must be knotted. These are known as ‘ ‘ drop threads. ’ ’ After the moulds are made, seasoned, and oiled, the young hand may begin by trying to make some easy marble, for a slab or chimney-piece. Gauge Keen’s extra superfine cement or superfine plaster, in a. large basin labelled No. 1, well mixing it until about the consistency of cream. This is pure white. Now pour a small quan¬ tity of this white plup into two small gauge-pots, Nos. 3 and 4. Pour a. third of what remains in the No. 1 pot into another gauge pot, No. 2. Take some black- colored pulp, and make No. 1 a blackish-grey. Color in the same way No 2. only very much blacker than No. 1. No. 3 is now slightly tinted with pulp from No. 1. This leaves No. 4 pure white. Then take a skein of twist (or threads), dip into No. 4, the pure white, and well charge it by stirring it about with the fingers; take out the threads, taking each end between the thumb and forefinger of each hand, and with the remaining fingers of each hand separate the threads, allowing plenty of MISCELLANEOUS MATTERS 279 ‘‘swag,” and strike this into the face of the mould, mak¬ ing each stroke at different angles, recharging the threads when necessary. Repeat this process with pulp from No. 3, but in a lesser quantity; then dip your finger ends into No. 2, and fling drops about the size of large peas all over the veining. These drops must be thrown on with considerable force, so as to cut into the veins as much as possible. Dip the fingers into No. 1, and throw on No. 2, using alternately from each gauge- pot until you get a uniform thickness of surface (scag), about y 8 inch in thickness. Now run a trowel over this to lay down any ridges. Cover the work with a piece of canvas, laying it evenly, smoothly, and without wrinkles. Be careful to put the canvas in the proper place, as moving it would spoil the lines of the veining; then spread a quantity of dry coarse Keen’s lightly over the entire surface. This will absorb any superfluous moisture through the canvas. After the canvas and coarse Keen’s have lain from ten to twenty minutes, or according to the stiffness of the gauge of the marble, the canvas and coarse cement are easily lifted off. Should any portion of the face of the scag leave the mould, and adhere to the canvas, it is taken off and put back in its place in the mould. The whole surface is now trowelled to render it dense and hard. The moisture should be sufficiently absorbed, or the trowelling may spoil the figure. The proper absorption of the moisture by the dry cement through the canvas, and well trowel¬ ling, are most essential to good work, ensuring hardness and density. The core or backing is now made by using the coarse Keen’s previously used for absorbing the moisture from the face, gauging it with some fresh coarse Keen’s as stiff as possible. This is laid on as thick as required. If 280 CEMENTS AND CONCRETES the face of the scag be veiy dry, spread a thin coarse gauged Keen’s, so as to give a perfect cohesion between the marble and the backing. The flat surface of the backing should always be ruled or floated straight with a uniform thickness, so as to give a true bed for the cast when it is taken out of the mould, and laid on a bench ready for stoning, stopping, and polishing. This can be done as soon as it is thoroughly set and hard, and in the same manner as scagliola. Marbles having long stringy veins require a different method of putting in the veins. Take the skeins, or “threads,” by the knot with one hand, and thoroughly saturate them with the veining mixture, and run the finger and thumb of the other hand down the threads to clear them of any excess of veining color with which they may be charged. Then give the end not knotted to your partner, holding the knot in your left hand. Pull the threads asunder, so as to take the form of the veins of the marble you are copying, then lay them in the mould, leaviqg the knots hanging over the edge of the mould, or at least visible, to facilitate their removal when required. The threads should be arranged on the mould so as to take the form of the veining. The other colored materials are then thrown upon the thread veins, which quickly absorb the coloring matter from them; care being taken that the various colors are thrown or dropped from the finger tips, to form the figure of the body of the marble that is being copied. When the mould is sufficiently and properly covered with the marbling, take hold of the knots and withdraw the threads. These should be cleaned by passing down the finger and thumb for future use, saving the superfluous stuff for filling up any holes in the marbling. The absorption of the use of canvas and dry coarse Keen’s, MISCELLANEOUS MATTERS 281 and the filling in of the backing or core, is then proceeded with as before described. Granites, porphyries, etc., are made in a different manner. For porphyries with white and black specks, make a slab of white Keen’s about % inch thick, and another in black, the same thickness. When they are set and hard, chop them into small pieces, then run them through a sieve, having a mesh to let through the pieces of the required size only. The pieces retained in the sieve can be broken and sieved again. The whole is now sieved again through a smaller mesh, which re¬ tains only the size wanted. The refuse can be used for small work or backing up. When the gauged stuff for the facing is mixed of the required tint (a reddish- brown), damp the black and white specks with the gauged color by means of a trowel and rolling, care being taken not to break the edges and faces of the black and white specks. When it is well mixed, lay it onto the face of the mould about 3-16 inch thick, press¬ ing it as firmly and evenly as possible. Then absorb the moisture by means of canvas and dry coarse Keen’s, trowel it well to give density, and fill in the backing or core as before. For “Rouge Royale,” “Verd Antique,” &c, requiring large white patches of irregular size, the sieving can. be dispensed with. The white pieces are broken haphazard, and pieces of alabaster can also be inserted in these, and many other marbles, due regard being given to the size and quantity, so as not to produce an unnatural effect. The remainder of the figure is formed with the “drop threads,” and the other colors being thrown cn. From this description of Marezzo, the workman will understand that in the case of marbles classed as “Brec¬ cias,” such as “Rouge Royale,” “Black and Gold,” &c., 282 CEMENTS AND CONCRETES having patches and rough jagged veins in them, he must have flat pieces of the required color previously made and broken up, or alabaster, as the case may be inserted into them, and the veining done with the £ ‘ drop threads ’ 7 and that fine or long veining threads are not required; that unicolored marbles require no veining threads; that the long veined marbles require the long threads, and in some cases the “drop threads” as well, and that granites, porphyries, &c., require no threads; that black is diffi¬ cult to make owing to the pure white cement requiring so much color; and finally, that in all cases, whether Ma- rezzo or scagliola, the polishing is done in a similar man¬ ner, whether using plaster or Keen’s cement. The details given must be carefully followed to pro¬ duce work artistic in figure and appearance. The direc¬ tions for making “St. Ann’s” so far as manipulation is concerned, apply to all others. A little patience, prac¬ tice, and perseverance will soon give confidence and ex¬ pertness in producing sound scagliola and Marezzo. Granite Finish .—Granite is a peculiar finishing coat of plaster which is sometimes used in this country to imi¬ tate granite. For granite finish, first render the walls with hydraulic lime, and when nearly dry lay with a thin coat of the same material but colored light brown. Then while this coat is still moist, splash the surface lightly with white stuff, then with black stuff, using only half as much as used for the white stuff. The red stuff is best applied by dotting the surface with a small brush charged with the colored stuff. After these colored lime stuffs are firm, but not set, the surface is carefully trow¬ elled, using the minimum of water so as not to mix the various colored stuffs. The surface is sometimes left in a rough state, or as left when splashed. After the surface MISCELLANEOUS MATTERS 283 is firm, it is- set out and jointed to represent blocks of graite. Granite Plastering .—Granite plastering is a method, introduced by the author, to imitate granite. This mode of imitating granite is based on the scagliola process. It is also somewhat similar to the granite finish, and gives better and more reliable results. The method of executing granite plaster work is as follows: First select the most suitable lime or cement for the situation, such as Portland cement or hydraulic lime for exterior work, and Parian or other white cement for interior work. Having decided on the material, gauge three different colored batches, one white, one red, and one black, taking care that the stuff is gauged stiff and expeditiously so as to obtain a hard substance. The material is colored to the desired shades, as described for scagliola or colored stuccos. When gauged the stuffs are laid separately on a bench and rolled until about 3-16 inch thick, and when nearly set they are cut into small irregular cubes and allowed to set and harden. The wall is then floated, ruled fair, and the surface keyed, and when set it is laid with a thin bedding coat of simi¬ lar stuff used for the floating, but colored light brown. The colored cubes are then mixed together in due propor¬ tions, and gauged with a portion of the light brown col¬ ored stuff and laid on the thin coat while it is soft. The whole is then firmly pressed with a hand-float until a close, compact, and straight surface is obtained, taking- care when pressing the stuff not to break the cubes. After the stuff is set and perfectly dry and hard, the surface is rubbed down and polished, as described for scagliola or for marble plaster. The bedding coat should be sufficiently thick to receive the colored cubes, other¬ wise the larger cubes will project at parts, and cause 284 CEMENTS AND CONCRETES extra labor in making a uniform and straight surface. Unless the cubes are fairly level when pressed, the sur¬ face will have a spotty appearance, besides being more difficult to polish. Where expense or time is a consid¬ eration, a striking appearance is obtained at less cost than polished work, by simply finishing the surface with a cross-grained hand-float, and a semi-polished surface is obtained by trowelling, or by scraping the surface with a joint-rule. Grey or light-colored granites are imitated by altering the colors of the cubes and the bedding coat as desired. Bold and striking effects on wall surfaces can be obtained by a combination of different colored granites, laid out in bands and borders. The effect can be increased by the introduction of borders in sgraffito, with the bands in granite plaster. / PART II CEMENTS AND CONCRETES, AND HOW TO USE THEM. It is not necessary to the workman that he should ex¬ pend a long period of his valuable time in reading up the history of cements and concretes, nevertheless it is proper he should be acquainted with the outlines of the origin, growth, and development of cements, concretes and their uses, and to this end the following brief his¬ torical summary is presented, sufficient to give the work¬ man a fair idea of the beginning and growth of the use of cements and concretes: The word concrete is of Latin origin, and signifies a mass of materials bound or held together by a cementing matrix. The Romans used concrete B. C. 500. They made good use of lime concrete both in the construction of buildings and roadways. “Roads,” says Gibbon, “were the most important element in the civilization of ancient Rome; and the cost of the Appian Way was such as to entitle it to the proud designation of ‘Re¬ gina Viarum’ (the Queen of Roads).” The Appian (the oldest of the Roman highways) was commenced by Appius Claudius Caius, when he was censor, about three centuries before the birth of Christ. It extended from Rome to Capua, whence it was consequently carried on to Tarentum and Brundusium. Antonio Nibby, an archaeologist of the highest authority, states that the Appian Way had an admirable substructure, with lime concrete materials superimposed, and large hexagonal 285 286 CEMENTS AND CONCRETES blocks of stone laid on the top of all. The Romans built concrete aqueducts, often several miles long, to convey water to the cities. The palace of Sallust, the historian, was built about B. C. 50, and was frequently used as a residence by most of the emperors until as late as the fourth century. It was partly burnt by Alaric in the year 410. This once magnificent edifice was erected on a strange site, partly in the valley at the foot of the Quirinal Hill, and partly on the top of the hill. The latter portion of the palace, which was of great extent, has been almost wholly destroyed by the builders of the modern boulevard. The walls, which were thick and high, Avere most valuable examples of the Roman use of concrete, unfaced by brick or stone. There is still visi¬ ble evidence, in the form of impressions left on those walls, which clearly demonstrates their method of cast¬ ing walls in situ by means of wood framing. Roavs of timber uprights, about 10 feet high, 6 inches Avide, and 3 inches thick, Avere fixed along both faces of the in¬ tended wall. Boards about 10 inches wide and iy 2 inches thick, in suitable lengths, were then nailed hori¬ zontally along the uprights, thus forming tAvo parallel wooden walls, into which the concrete was laid and rammed until the space between the boards was filled to the top. When the concrete had set, the Avood fram¬ ing was removed, and refixed at the top of the concrete, the whole process being repeated until the wall was raised to the required height. This concrete was far more durable than brick or stone. The jerry-builders of the modern Rome had no difficulty in pulling down the stone wall of Servius, but the concrete walls required the use of dynamite to complete their destruction. After Avithstanding the wear and tear of many centuries, and the repeated onslaughts of the Goths and Vandals, it Avas HOW TO USE THEM 287 left to the nineteenth-century speculative builder to de¬ stroy those interesting remains. The use of concrete for floors and roofs is of great an¬ tiquity. It was employed for this purpose by the Ro¬ mans in the time of Julius Caesar. Professor Middleton, in his first book, “Ancient Rome,” states that the whole of the upper floor of the Antrium Vesta is formed of a great slab of concrete, 14 inches thick, and about 20 feet in span, merely supported by its edges on travertine cor¬ bels, and having no intermediate supports. In his sec¬ ond book, “The Remains of Ancient Rome,” Professor Middleton mentions that the Romans used concrete for the construction of the Pantheon, which was erected about the time of Christ. A curious and apparently un¬ accountable feature as regards practical purposes is that the concrete is faced with bricks, which were faced again either with stucco or (in special cases) with marble veneer. The Professor gives a sketch showing the ex¬ terior facing and the section of a wall of this kind, the entire mass being composed of concrete, except a facing of thin bricks, triangular in plan, with the points in¬ wards. As the author observes, these bricks could not possibly be intended as a matrix for concrete, as it would not have withstood the pressure of the latter while in a wet state. It must therefore have been necessary to re¬ tain the brick and the concrete with an external tim¬ ber framing, as in the case of unfaced concrete. There could be no gain of strength or other benefit to compen¬ sate for the time expended setting the brick skin. The dome of the Pantheon is 142 feet in diameter and 143 feet high. This is also formed with brick-faced concrete. It has often been described and even drawn by various authors as essentially a brick dome. Professor Middle- ton remarks there must have been very elaborate con- 288 CEMENTS AND CONCRETES struction of centring for this and other massive concrete vaults. He states they employed a method, which has become common of late, to avoid the necessity of build¬ ing up the centring from the ground. They set back the springing of the arch from the face of the pier, so as to leave a ledge from which the centring was built, the line of the pier being afterwards carried up until it met the intrados of the arch, leaving it a segmental one. The Professor also found signs of timber framing for walls in the remains of the Golden House of Nero, un¬ der the Thermae of Titus, where, he says, “the chan¬ nels formed by the upright posts are clearly visible. These upright grooves on the face of the wall are about 6 inches wide by 4 inches deep, and they are afterwards tilled up by the insertion of little rectangular bricks, so as to make a smooth unbroken surface for the plaster¬ ing. ” This method is difficult to understand. Accord¬ ing to the present practice, the supports should be fixed outside the line of wall surface and leave no space to fill in afterwards. He also mentions a striking example of the tenacity of good concrete in the Thermae of Cara- calla, at a part where a brick-faced concrete wall origin¬ ally rested on a marble entablature supported by two granite columns. “In the sixteenth century,” he says, ‘ 4 the columns and the marble architrave above them were removed for use in other buildings, and yet the wall above remains, hanging like a curtain from the concrete wall overhead. ’ ’ This proves that the Romans bestowed as much thought and care on the materials and their composition as they did on their construction. Profes¬ sor Middleton notes that the larger pieces of aggregate in the concrete, which are not close together, are so evenly spaced apart as to lead to the conclusion that they must have been put in by hand, piece by piece. HOW TO USE THEM 289 Dr. Le Plongeon, during liis explorations in Peru, found many remains of mud concrete walls. Although, they were built many centuries ago, they have proved sufficiently durable to exist until to-day. The materials were placed between two rows of boards, and well beat¬ en, and the exteriors were sometimes decorated with plas¬ ter work. Thus it appears that the Peruvian builders of the period of the Incas anticipated by centuries the method (but not the material) of our modern concrete buildings. Le Plongeon’s researches conclusively estab¬ lish the fact that these Indians were masters of concrete building and plastering. The walls of the fortress of Ciudad Rodrigo in Spain are built of concrete. There are over twelve miles of arches and tunnels constructed with concrete in the Varone Aqueduct, which supplies Paris with water. One of the arches over the Orleans Road, in the Forest of Fontainebleau, has a span of 125 feet without a joint, the arches and the water-pipe or tunnel being entirely composed of beton, made with Portland cement, hydraulic lime, and the sand found on the spot. Concrete blocks weighing over 20 tons were used in the construction of the Suez Canal, 3,000,000 tons of these blocks being required at Port Said alone. Besides the unquestionable durability of concrete, it also possesses fire-resisting and waterproof powers of the highest degree. Constructional works formed with con¬ crete carefully made and applied may be considered ab¬ solutely fire-resisting and damp proof; in fact, in these respects concrete has long since passed the experimental period, inasmuch as numerous tests, under the most try¬ ing and adverse circumstances, attest the superiority of this material for sanitary and durable work. The best concrete in France is that made under Coign- et’s system of “beton agglomere,” and has been used 290 CEMENTS AND CONCRETES with great success in the construction of various large and important works. In Paris many miles of the sew¬ ers have been formed of this material, and a church in the Gothic style, from the foundations to the top of the steeple (which is 136 feet high) is entirely formed of beton. The work was prosecuted without cessation for two years, and was exposed to rain and frost, but has not suffered in the slightest way from the extremes of tem¬ perature. The strength of this material for constructive work may be judged by the thickness, or rather want of thickness, in the construction of a house, six stories high, having a Mansard roof—cellar, 19 inches, first story, 15 inches; second story, 13 inches, and diminishing 1 inch every successive story, so that the sixth story was 9 inches. The cellars have a middle wall from back to front, from which spring flat arches having a rise of one- tenth of the span, the crown being 5 inches thick, and at the springing 9 inches, which formed strong damp- proof and fireproof cellars. There are many houses in Paris, and this country, constructed of this material. It has been used in London in the construction of sewers, &c. This concrete is composed of Portland cement, sand, and lime. Hydraulic lime is used for sewers and waterworks, and common lime for ordinary work. The lime is used in a powdered state. The whole of the ma¬ terials are mixed in a dry state by hand, and afterwards gauged in a specially made pug-mill. The least possible amount of water is added by means of a fine jet while the pug-mill is in motion. The mixture is then spread in thin layers, and beaten by rammers formed of hardwood. The quantities for coarse work, where a fine face is not required, are: Portland cement, 1 part; common lime, y 2 part; gravel, 13 parts; coarse and fine sand, 6 parts. And for sewers: Portland cement, 1-5 part; hydraulic IIOW TO USE THEM 291 lime, 1 part; sand, 6 parts. And for external work of good quality: Portland cement, 1 part; lime, i /2 part; sand, 7 parts. The above proportions are all by meas¬ ure. Specimens of Coignet beton at two years old have attained a crushing strength of 7,400 lbs. to the square inch. Fine Concrete .—“No book on plastering, ” says Miller, “would be complete without a description of the meth¬ ods for working ‘fine concrete’ (here termed ‘fine con¬ crete’ to distinguish it from rough concrete as used for foundations, &c.), which is now coming into general use for paving purposes, staircases, and constructive and decorative works for buildings. Floors, roofs and simi¬ lar works which are finished with fine concrete, being within the plasterer’s province, also demand description. The proper manipulation of the plastic materials, which is imperative for sound concrete, is undoubtedly plaster¬ er’s work. The higher branches of concrete work, for architectural construction and decoration, embrace model-making, modelling, piece-molding and casting. Concrete construction is therefore essentially a part and parcel of the plasterer’s art and craft. The construc¬ tion of concrete staircases in situ affords a striking ex¬ ample of the necessity of employing plasterers. Only a plasterer can manipulate the materials correctly, make the nosing mitres sharp and true, and set the soffits of the stairs and landings, and form a true arris at the stringing, whereas the non-plasterer leaves the work un¬ even, rough and unsound. The non-plasterer can just manage to spread the stuff laid on the ground for him when laying paving, but he is entirely lost when the stuff has to be taken up on a hawk and laid with a trowel on an upright or overhead surface. He then gets upset, or rather he upsets the stuff. The non-plasterer 292 CEMENTS AND CONCRETES possibly may have been an unfinished apprentice, or a dunce at his former trade, hence his trying another. These remarks are not caused by any hostility to other trades, but are inspired by the fact that many failures in the better class of concrete are due to the non-plaster¬ er’s incapacity in working, and his lack of knowledge of the materials. Portland cement concrete pavements were first used about sixty years ago. Its introduction, im¬ provements, and subsequent rapid strides for paving, and in the construction of staircases, cast and made in situ, are due to the plasterers. Concrete is one of the best materials for paving the sidewalks of streets, abat¬ toirs, stables, breweries, &c. It is j.intless, impervious, non-slippery, and can be laid with a plain surface or grooved to any desired form. The only objection to paving laid in situ for streets is that when it is cut to repair or alter gas or water pipes it is difficult to make it good without the patches showing. This slight defect can easily be overcome by cutting out the whole bay where the patches are, or by forming a movable slab over the pipes. There has been in recent years some controversy as to the department of the building trades to which lay¬ ing concrete paving properly belongs. The claim is un¬ doubtedly upheld in the strongest way for the plaster¬ ers. A further argument, if one is needed, to identify the operation as a plasterer’s job, is that the tools, skill in which is necessary, are exclusively those of plaster¬ ers. The laying trowel and the hand-float are prin¬ cipally used, and none but plasterers exclusively employ them, no other workman in any branch of the building trades being habituated to their use. In every part of the world where concrete paving has been used it has HOW TO USE THEM 293 been laid down by plasterers, so that it may be looked upon as their legitimate sphere of work. Concrete is now extensively used in preference to earthenware for making sewer tubes. Experience has proved that the acids present in liquid sewage and the gases generated by the action of a faecal decomposition do not injure the concrete tubes, but on the contrary tend to harden them. Among the many unlikely purposes for which concrete has come into use may be mentioned stat¬ uary, vases, fountains, sinks, tanks, cisterns, cattle- troughs, silos, railway sleepers, platform copings, man¬ telpieces, chimney pots, tall chimneys, tombs, tombstones, and coffins. Concrete is slowly but surely coming to the front as one of the most useful, economical, constructive, and decorative materials for works requiring strength and endurance. It may now be said to be indispensable to the architect, engineer and builder. Concrete, when properly made with a Portland cement matrix, and slag or a similar aggregate, is undoubtedly the best fire-proof material used in any building construction. It can be made thoroughly waterproof and acid proof, and may be moulded or carved to any design and colored to any shade. After this brief historical review of concrete, the practical considerations of the modern working by plas¬ terers claim attention. Before describing the methods of working the concrete, a description of the materials, with their characteristics and application, is given as a preliminary guide and reference. Matrix .—Matrix is a word used to designate any ma¬ terial having a setting, binding, or cementing power, such as limes, plaster or cements. For concrete paving, stairs, floors, or cast work for external purposes, it may be truly said that there is only one matrix, namely, Port¬ land cement. 294 CEMENTS AND CONCRETES Aggregate .—This is a term applied to those materials held or bound together by the matrix. Aggregates may be fibrous or non-fibrous, natural or artificial. The nat¬ ural aggregates comprise granite, stone, shells, marble, slate, gravel, sand, metal filings, &c.; the artificial slag, brick, pottery, scharff, clinkers, coke-breeze, ashes, glass, &c.; and the fibrous slag, wool, coir, fibre, reeds, hair, cork, tow, chopped hay, straw, shavings, &c. The fibrous aggregates while being principally of a natural kind, are generally of a vegetable nature. They are commonly used with a plaster matrix for the interior works. The best aggregates for the upper coat of concrete paving are granite, slag, and some of the hard limestones. The best and cheapest for the first layer or rough coat are broken bricks, old gas retorts, clinkers, whin and other stones. Stone chippings from masons’ yards and quar¬ ries are cheap and good. Shingles and gravel are also used, but owing to their round and smooth surfaces they afford little or no key for the matrix. When found in large quantities and at a cheap rate, they should be broken to render them more angular, so as to give a bet¬ ter key. Aggregates are broken by a crushing or stamp¬ ing machine. In Paris, the stone aggregates used for casting figures, vases and similar ornamental works is generally broken by hand. Aggregates should be clean, and their surfaces free from mud and dust. Coarse aggregates are easily cleaned by turning on a strong stream of water from the hose. The aggregates should be laid on an inclined plane to allow the water and dirt to run off. The importance of a clean aggregate is seen from the fact that briquettes made from washed particles resist a tensile strain from 15 to 20 per cent, higher than those made from unwashed particles, when tested under similar conditions. HOW TO USE THEM 295 Porous Aggregates .—All aggregates of a porous na¬ ture or having a great suction should be well wetted before being gauged, to prevent absorption of the water used for gauging the matrix. A porous aggregate re¬ quires more cement than one of closer texture, and is not as strong. Water has no power to harden or set an aggregate. It is used to render the mass plastic, and to set the cement. No more than is necessary for this pur¬ pose should be used. Sloppy cement will not attain the same degree of hardness as a firm or stiff gauged cement, consequently it stands’to reason that if the water or a part of it be absorbed by a porous aggregate, it will ren¬ der the matrix, or that part next to the aggregate, friable and worthless. This may be proved by gauging a part of neat cement and spreading it on a brick and another part on a slate. It will be found that the latter will set and become hard, whilst the former will either crumble before setting, or partly set, without getting hard. All aggregates are more or less absorbent, but while the por¬ ous kinds will absorb the water from the matrix, not only leaving the portions in immediate contact with the aggregate inert, but also weakening the whole body of the concrete, the non-porous have little or no absorption, water being retained in the matrix, or a portion may lie on the surface of each particle of aggregate, thus tend¬ ing to harden the matrix and increase the general strength of the concrete. It may be thought that these defects are trivial, and can be overcome by thoroughly saturating the porous aggregate to prevent suction, but the fact still remains that after this or other excess water has dried out, the body of the concrete must still be por¬ ous, and this is one, if not the principal reason, why some concretes are not damp-proof. The quantity of matrix used for ordinary concrete being very much less 296 CEMENTS AND CONCRETES than the quantity of aggregate, and the matrix not being of sufficient thickness to resist the force of atmospheric moisture, the damp finds a ready passage through the porous portions. A mass of porous aggregate will ab¬ sorb external moisture, and this will gradually work through the body to the weakest or driest surface, or be retained for a time, according to the state of the atmos¬ phere. The extra keying power claimed for a porous aggregate is infinitesimal. It may be said not only to be of no value, but unnecessary, bearing in mind that in well-made concrete every particle of aggregate is envel¬ oped with matrix. Another point to be considered is the great tenacity of Portland cement to most clean surfaces, however smooth. Many men will have noticed how it clings and adheres when set to iron, even to the smooth blades of trowels and shovels. The ultimate tenacity of neat Portland cement after being gauged twelve months is about 500 lbs. per square inch. Compound Aggregates .—The proper selection and use of aggregates for a true concrete is not secondary, but of equal importance to the matrix. As inferior aggre¬ gates are in the majority, it is advisable to take their de¬ fects into consideration. For concrete floors, roofs, and stairs, where strength, durability, and fire resisting prop- erites are imperative, gravel and coke-breeze as aggre¬ gates stand lowest in the scale. Owing to their abun¬ dance and cheapness, however, or for want of better ma¬ terials, their use is often unavoidable. Their individual defects may be partly if not wholly corrected by a com¬ bination of two or more aggregates so as to balance their respective good and bad qualities. It is self-evident that the hard, non-porous, and incombustible nature of gravel will correct the soft, porous, and combustible nature of HOW TO USE THEM 297 coke-breeze, and that the light, rough, angular, and elas¬ tic nature and variety of size of coke-breeze will counter¬ balance the disadvantages of the heavy, smooth, round, and rigid nature and uniformity of size of gravel. The strength, irregularity of size, and form of broken bricks and its incombustible nature, causes it to be a direct gain to either of the above. The mixing of various aggre¬ gates may seem of small importance, but if by their judi¬ cious amalgamation the strength is enhanced, or the weight or cost of the material decreased, or gained, if the practice enables any waste or by-product to be utilized, then the advantage becomes obvious. To argue by analogy, it is well known that it is by the judicious com¬ bination and manipulation of various materials that mortars and cements attain their strength and hardness, therefore the same course will give equally good results with concretes, while rendering economy with safety pos¬ sible. The compressive and tensile strength of concrete is influenced both by the matrix and the aggregate. Aggre¬ gates which are uniform in size (or if of various sizes which are not graduated in proportion to each other), or having their surfaces spherical, soft or dirty, will not bind with the matrix, or key or bend with each other, so well as those which are of various graduating propor¬ tional sizes, and have their surfaces hard, angular and clean. Sand and Cement .—Sand is extensively used as an aggregate in Portland cement for cast work, mouldings, and wall plastering. Fine sand does not give so good results for strength as coarse sand, and a hard-grained sand is more durable than a soft one. Ground brick¬ bats or pottery, sandstone and flints, fine gravel, smithy 298 CEMENTS AND CONCRETES ashes, and coke-breeze are often used as substitutes for sand. It lias generally been assumed that sharp coarse sand is one of the best and strongest for gauging with cement, but, according to experiments made by Mr. Grant, clean sharp pit sand gives better results, as he found that whereas test briquettes having a sectional area of 2 14 superficial inches, composed of equal proportions of coarse sand, broke at the end of twelve months with a tensile strain of 724 lbs., it required 815 lbs. to break briquettes composed of equal parts of cement and pit sand. With reference to various sands suitable for mak¬ ing mortar with cement, Mr. Grant’s experiment is of a most surprising nature, as it indicates that sand made from ground clay ballast, or ground brick—which are identical—and Portland stone dust, were superior to pit or sea sand, or smiths’ ashes. The following shows the results of tests of various aggregates made by Lieutenant Innes. The briquettes are composed of Portland cement, sand, or other aggre¬ gates, in the proportions of 1 to 2, and were kept in water for seven days. It will be seen that Portland stone dust gave the best results, and the others follow in this order—coarse sea sand, rough pit sand, smooth pit sand, drifted sea sand, and lastly smithy ashes. If the dust had been elimi¬ nated, the tests would be more valuable. The degree of coarseness has a considerable influence on the strength of the concrete and mortar. Fire sand makes weaker mortar than coarse. The following table gives the re¬ sults of two series of tests carried out by Mr. Grant. The cement was sifted through a sieve with 2,580 meshes to the square inch, and was made into briquettes with 2 Tests of Various Sands, &c., and Cement. HOW TO USE THEM 299 J3 O a 83 3 O' o> a c a £ a .a be a o CO tO 00 os CO 00 05 to r—( CO 1C Three Months 529 249 193 248 175 254 91 Propor¬ tional Value of Sands. 52.4 22.3 40.1 34.9 61.3 14.1 rti w o o o 00 tT to oo XJ 0) to nr CO o 05 CO CO nfi rH rH rH BD 1) a > g ‘SO® go ■” C5 53 ■£ 05 00 1C CO CO tO co tO i 5fa 85 4) a « ■S ». A a> (B a co co oo tO 0) a -J ,§§ S « o k a> £ CO CO CO 05 •tfl CO nr CO 00 CO eo nr © a 3 T3 3 03 § a> •S’S • i - ^ jo ® 00 3 3 O o © 2 « ” • rH ^■H _r"£ T3 . 13 ^ oS T3 co © • rH ^ © © m a oj © CO 3 O © © • pH • rH GO T3 a> «H-H *c T* <3 CO GO a • i—H C3 *H W) •8 a) °° ® 3 32 O o3 © a 32 CO .i-l . - CD 00 3 gj* ’3 .2 ‘3 ® 3 ^ ° 3. -3 2 §§ s u o «*-H • pH 3 3 TJ 3 .3 • 4*1 o o a CD CD •2 3 2 § oo-s T3 3 03 A 00 3 o Sh GO 3 • pH o3 Jh b£ GO 3 ^ a © g o V no 3 o3 CD PM CD "3 3 »““H ■e o Ah 5* 3 00 © tH a *51 3 © 3 X> 3 3 3 *3 © © 3.2 8 n3 3 00 oj .2 rC a M o Sh GO fl • rH « cC cd K © 00 .3 - ID *5» C« 2 3 t^n3 .12 o a ° co <3 4A fl o o 300 CEMENTS AND CONCRETES parts of sand by weight. All the briquettes are kept in water. Tensile Tests of Portland Cement and Sand (Coarse and Fine). No. Sand tested by Sieves. At 28 days. 60 days. 91 days. 182 days. 273 days. 364 days. t First Series— Nos. lbs. lbs. lbs. lbs. lbs. lbs. 1 1 cement to 3 sand. 20-30 78.5 113.9 116.9 142.3 178. 205.5 2 ditto. 10-20 137.1 239.5 223. 231.5 254.5 251.5 Second Scries— 3 1 cement to 3 sand. 20-30 117.2 134.5 145. 156. 157.8 21§. 4 ditto. 10-20 212. 236.5 206. 253. 267.5 273.5 In the above each figure is the average of ten tests, the result being given in pounds per square inch. The sand used in tests 1 and 3 passed a sieve with 400 meshes to the square inch, and the sand used in the tests 2 and 4, through a sieve with 100 meshes to the square inch. Fireproof Aggregates .—The selection of the best known fire-resisting aggregate for fire-proof concrete construction is of vital importance. Granite, stone, and flints splinter and crack when subjected to great heat, or to the sudden reaction caused by cold water used for extinguishing fires. Coke-breeze concrete, when under the influence of intense heat, as for example in the midst of a building on fire (stated by Captain Shaw to be from 2000 degrees to 3000 degrees Fahr.), will gradually calcine and crack, and finally fall to dust. Slag is one of the best fire-proof aggregates. It is a well-worn axiom that “what has passed through the fire HOW TO USE THEM 301 will stand the tire.” There is no other material that has passed the ordeal of fire like slag. Its great hardness, density, and angularity (when crushed) all tend to make it one of the best substances for fire-proof construction. Slag is cheap and abundant, but requires great care in selection, as some kinds contain a large amount of sul¬ phur, which is very detrimental to Portland cement, causing the concrete to blow and expand. The presence of sulphur can often be detected by the smell alone. When sulphur is present in a heap that has lain for some time, or sufficiently long to allow the atmosphere to cleanse the outer surface, it is more difficult to detect. A hole should then be dug in the heap, and the presence of sulphur can be ascertained by smell, heat, and color. It will smell strong, and if new will be warm, and show •yellow patches. The power of the sulphur is so great that washing the slag once will not entirely cleanse it. In some cases frequent washings and long exposures to the air are necessary. There are some slags that are free or nearly so from sulphur, and which can be had direct from the iron furnaces. The slag from coal and iron furnaces is largely employed for concrete paving. It is hard and practically free from sulphur. The best size is % inch screenings. This when sifted yields a fine kind for topping, and the residue is useful for the rough coat. The next best fire-resisting aggregates are fine-bricks, pottery, scharff, hard clinkers, and pumice-stone. The last has the advantage of being extremely light, but it is too soft for the frictional wear. Coke-breeze may to a certain extent be deprived of its combustible nature and rendered more fire-resisting by washing and passing it through a ^ inch sieve, then adding 1 part flowers of sulphur and 10 parts fine broken bricks to 20 parts of coke-breeze. The larger breeze rejected by the sieve can 302 CEMENTS AND CONCRETES be broken small, or used for internal layers of concrete. The bricks should also be passed through a % inch sieve. The finer the breeze and brick, the better for receiving and retaining nails. Voids in Aggregates .—The quantity of voids or in¬ terstices depends on the shape and size of the aggregates. The least quantity of voids will be found in those aggre¬ gates which are broken small, and contain pieces of va¬ rious sizes. Gravel free from sand contains about 30 per cent, of voids, and broken stone of uniform size about 50 per cent. Sand is often mixed with gravel, stones, &c., to lessen the quantity, or fill the voids, so as to en¬ sure the full strength of the concrete, without adding more cement than the proper ratio. The following method is used to ascertain the voids in aggregates:— Fill a box of known capacity with damp, broken aggre¬ gate ; start shaking it during the operation; then fill the box to the brim with water; the quantity of water is the measure of the voids in the aggregate. Having now briefly reviewed the characteristics of the aggregates most used, the practical conclusions to be drawn are that they should be angular in form, hard in nature, grad¬ uated in size, and clean. Crushing Strength of Concrete .—The crushing strength of concrete depends upon the ratio of cement, and the nature of the aggregate. Another important factor is compression, done by heating and ramming. Compression increases the weight of concrete about 4 per cent., and the strength about 25 per cent. The follow¬ ing table shows the crushing strength of concrete made with Portland cement and various kinds of aggregates as given by Mr. Grant. The tests were made with 6-inch cubes. One-half were compressed by heating the con¬ crete into the mould with a mallet; the other half were HOW TO USE THEM 303 not compressed. The whole were kept in the air for a year before being crushed. The granite and slag might have been expected to have given the better results. It is probable that they were unwashed, and contained a considerable amount of dust. If the compression was done by hydraulic power, so as to obtain a uniform compression in all the cubes, the results would be more reliable. Crushing Strength (in Tons per Square Foot) of Portland Cement Concretes Having Various Aggregates. Nature of Ag¬ gregate. Six to One. Eight to One. Ten to One. Com¬ pressed. Not Com¬ pressed. Com¬ pressed. Not Com¬ pressed. Com¬ pressed. Not Com¬ pressed. Ballast. 81.6 72.8 54. 50. 42. 32. Portland stone 162.4 120. 132. 98. 88. 76. Granite. 122. 98. 78.4 58. 62. 46. Pottery. 115.2 98.4 88. 72. 74. 56. Slag. 92. 80. 78. 56. 42. 34. Flints. 82. 62. 70. 56. 60. 51.2 Water for Concrete .—Water for concrete should be perfectly clean, and free from organic and inorganic impurities. As regards the quantity, it can only be said that for such purposes as the foundations for pav¬ ing, casting blocks, &c., or where the material can be well rammed, so as to insure perfect consolidation, less is required than where the concrete can only be poured or laid in position. When mixed with sufficient water, the concrete occupies about one-eighth more space than when 304 CEMENTS AND CONCRETES mixed with the full quantity, and percolation through the former gauge would be greater than through the lat¬ ter. Yet by thorough ramming the former would oc¬ cupy less space and offer greater resistance to moisture. An over-watered gauge is slow to set, difficult to work, liable to surface cracks, and often there is a loss of strength, caused by escape of a portion of liquid cement. The work will also be unequal in strength, owing to the liquid cement flowing to various or lower parts, leaving parts of the aggregate bare and weak. It must not be inferred from the foregoing remarks that water is entirely unnecessary or of little value for concrete. On the contrary, it is of the utmost value. The evil is in the abuse, not in the use. Portland ce¬ ment has a great affinity for moisture. For instance, if a sack of cement is left on or in a damp place, a part of the contents soon becomes set and extremely hard, which is a proof of its affinity, and that moisture alone will set cement without water, far less excess of water. Fresh cement requires more water than stale cement. Cement gauged with sea water sets more slowly than with fresh water. Sea water should not be used in concrete in¬ tended for paving stables, chemical tanks, or similar places where it will come in contact with ammonia. Sea water having a lower freezing-point than fresh water, is sometimes used in frosty weather to allow the work to be carried on. It ought not, however, to be used for ex¬ ternal work, especially for plastering facade as it has the property of attracting moisture and causing an ef¬ florescence on the surface. Sometimes in frosty weather hot water, also hot lime, is used for concrete; but al¬ though these hasten the setting and hardening of con¬ crete, they also wash away some of the finest and best particles of the cement during the gauging. A part of HOW TO USE THEM 305 the water also forms in little globules throughout the mass, ancl when the water-drops evaporate a series of small holes or bulbs are left, which deteriorate the strength of the concrete. Finally, it may be stated that the quantity of water required for gauging concrete is regulated by the class and condition of the aggregate, by the state of the atmosphere, and by the purpose for which the concrete is required. Another important point is the careful and thorough incorporation of all the ma¬ terials when gauging. A mass of raw materials, if gauged carelessly, will require more water to attain the same plasticity than that which is carefully gauged. Ap¬ proximate quantities of water are given for Portland cement plastering. For concrete the quantity is about 21 gallons of water to 1 cubic yard of dry materials, or about 1 part by volume to 8 parts. It is a good maxim to bear in mind when mixing water for concrete, that other things being equal, the minimum is better than the maximum. Water may be said to give birth to the strength of cement; to carry the simile further, the ag-C gregate may be termed the bone, the matrix the skin and sinew, and the water the blood of concrete. Gauging Concrete .—It is a common idea that concrete can be gauged and used anyhow, with any aggregate, or with any amount of water; and in consequence of a lax¬ ity in supervision in the selection of the materials, and their correct gauging and manipulation, unsatisfactory results are sometimes arrived at, the blame being at¬ tributed to the wrong cause. Gauging concrete re¬ quires considerable care to avoid waste of the materials and obtain the best possible work. Concrete can be gauged either by hand or by machinery. For small quantities, such as for stairs and similar work, the former is almost invariably used; and for large quan- 306 CEMENTS AND CONCRETES tities, such as for foundations or buildings, &c., the lat¬ ter, being more economical, is preferable. A careful and uniform method should be employed for hard gauging; nothing should be left to chance or rule of thumb. The gauge-board should be sufficiently large to allow the materials to be turned over without spilling, it should be placed as near the work as possible, and it should be cleaned after eacli gauge. For fine concrete, no more than 1 cubic yard should be gauged at a time. This is as much as three men can properly gauge at once and in the proper time—that is, before the “initial set” begins. Portland cement con¬ crete, unlike some mortars, does not improve by pro¬ longed working. If larger quantities are desirable, then more men must be employed in the gauging. All ma¬ terials should be measured for each gauge, to ensure uni¬ form setting and strength, and also the best work. This, combined with the saving of time and materials, will re- pay a hundredfold the cost of the measures. It is a common yet a wrong way, when gauging for paving pur¬ poses, to measure the aggregate by so many barrowfuls to a sack of cement. Neither the aggregate nor the ce¬ ment can be accurately measured in this haphazard way. No man fills a barrow twice alike, and the cement being turned out of the sacks direct onto the aggregate is apt to vary, as it may contain lumps caused by damp, and very often some of the finest cement is retained in the sack, as more often than not it is simply drawn up and then thrown on one side without shaking it, as would be, cr at least should be done if the cement was emptied for air-shaking. The aggregate should be measured in a bottomless box or frame with handles at the ends, the cement in a box (with a bottom), and the water in a gallon metal measure or a pail made to contain 4 gal- HOW TO USE THEM 307 Ions. Five pailfuls of this size are about sufficient to gauge 1 cubic yard where the concrete can be well rammed or punned. For work that is simply laid, 1 gal¬ lon extra is required. The box frame is laid on the gauge-board and filled with aggregate (in a damp state). The frame is lifted off, and the aggregate spread over the board until about 6 or 7 inches thick. The cement is then distributed over the aggregate. The materials are then gauged by three men, two with shovels, and one with a rake or larry, the former facing the latter. The dry materials should be carefully but energetically turned over twice or even thrice, and then when being turned over the third time water must be gradually ad¬ ded by means of a rose fixed on a water-can. Water poured from a pail is apt to wash parts of the cement away; the water also cannot be regularly and gradually distributed over the dry materials as when a rose is used. The mass is again turned over twice or even thrice, until thoroughly incorporated. This turning over does not consist of merely turning the mass over in the centre or on one place of the board, but to be effectively done a shoveller should stand at each side of the board, and the raker at the end to which the mass is to be first turned; the shovellers lift the stuff and spread or rather scatter it on one end of the board with a jerking mo¬ tion, and the raker further mixes the stuff by working each shovelful backwards and forwards. This is repeat¬ ed, the stuff being turned to the other end of the board, after which it is turned to the center, the water being added as already described. The wet mass is then turned over twice in a similar manner, and finally finished in the centre of the board. The shovellers in the final mix¬ ing turn the stuff from the outside of the heap to the centre, while the raker gives the final touches. After 308 CEMENTS AND CONCRETES being gauged, it should not be disturbed, but immediate¬ ly shovelled into pails, and conveyed to the place of its use. The “initial set” begins nearly or as soon as gauged, and any after or unnecessary disturbance tends to de¬ stroy the setting properties of the cement. The practice of gauging, and afterwards regauging or knocking it up, is most objectionable, as it destroys its setting properties. No more should be gauged at one time than can be con¬ veniently laid in one operation. The gauging of this valuable material should not be left entirely to unskilled labor, but ought to be carried out under careful super¬ vision. Ramming Concrete .—The ramming, beating, or pun¬ ning of concrete is of great importance. It compresses the concrete, rendering it more dense and free from voids, and forces out all superfluous water. The re¬ sultant gain in strength, durability, and imperviousness is by no means to be despised. Without compression it is impossible to obtain impervious concrete. Prolonged ramming, however, is dangerous, as it may be contin¬ ued until the cement is set, which would be a direct loss of strength. For this reason, the ramming of concrete made with quick-setting cement should immediately fol¬ low the deposition of the material, and be expeditiously done. The concrete should always be gauged rather stiff than soft. If in the latter form, the ramming will separate the more fluid portions, and produce strata of different densities. When the concrete is deposited in layers, the joints of each layer, if dry or exposed, should be well swept and watered before the next layer is de¬ posited. It is often advisable, especially in very dry work, to brush the joints with liquid cement after they have been swept and wetted. For larger constructional work, the joints should also be keyed by aid of a pick, or HOW TO USE THEM 309 by inserting stones at intervals into the concrete before it is set ? leaving them projecting 3 or 4 inches above the level of the joint. Another method of forming a key is effected by forcing a batten on edge about 2 or 3 inches deep into the concrete, at the middle of the joint, and when the concrete is firm or nearly set the batten is ex¬ tracted, thus leaving a groove which forms a key for the succeeding layer. No layer that has to be left for some time, or until dry, should be less than 4 inches deep. Thin layers are always a source of weakness. If the successive layers can be laid before the previous one is firm or set, the thickness is not of so much consequence. For large work, when each layer has to stand until set, the thick¬ ness may vary from 9 to 12 or even 18 inches. Ham¬ ming may be done by using an iron punner, or one made of hardw’ocd and bound with iron. Wooden mallets and punchers or iron hand-floats are most suitable for ramming stairs and cast work. The gain in strength is shown in the table of the crushing strength of Port¬ land cement concrete. Thickness of Concrete Paving .—The thickness of con¬ crete paving laid in situ is regulated according to the purpose and the position of the work. The thickness al¬ so depends upon the nature and solidity of the founda¬ tions. It is obvious that a thicker paving is required for a foundation that is weak or soft than for one that is strong and hard. The best foundations are those com¬ posed of strong and well-laid rough concrete. Founda¬ tions composed of broken bricks or stone thoroughly con¬ solidated by ramming are the next best. The thickness of foundations is also regulated by the nature of the soil and the subsequent traffic. Paving for the sidewalks of mam streets, or where the traffic is heavy and con- 310 CEMENTS AND CONCRETES tinuous, should not be less than 2 inches. For a medium traffic, and on a strong foundation, a thickness of iy 2 inches will be sufficient. For side streets, garden paths, passages in houses, or similar places where the traffic is light and limited, a thickness from 1 to iy 2 inches will be ample if on a rough concrete foundation; but if on a dry “dry,” that is, broken brick or stone one 2 the thick¬ ness should not be less than 1 y 2 inches. The thickness for stable floors may vary from 3 to 4 inches, according to the class of horses. For instance, a thickness of 3 inches would be ample for race or carriage horses, but 4 inches is necessary for heavy cart horses. The same rule applies to yards, a thickness of 3 or 3 y 2 inches being sufficient for carriages, while 4 inches is required for carts, wagons, &c. Factory floors are generally made 2 inches thick, but where there is machinery or wheel traffic a thickness from 2 y 2 to 3 inches is employed. By computing the volume and nature of the traffic, and comparing the tests of concrete paving given herein, the requisite thickness will be readily obtained. It must of necessity greatly depend on the class of the materials and manipulation used for the paving. Like most other articles, a good material will go further and last longer than a bad one. Concrete Paving .—Good pavements proclaim a city’s progress. Isodorus states that the Carthaginians were the first people to pave streets. The subject of paving and floors will be best understood by dividing it into two parts—namely, paving, which is a floor surface laid and resting on solid ground; and floors, by which are meant floors over voids. The following items briefly embody the processes used for most concrete pavings now in use. Paving in situ is either laid in “one coat” or “two coats,” the latter being in more general use than HOW TO USE THEM 311 the former, yet each method has its individual merits. One-coat work is not so liable to rise or laminate as two- coat work. It takes slightly less labor, the whole thick¬ ness being laid in one operation. The aggregate is either granite or slag, or both in equal proportions, gauged with Portland cement in the proportion of 2 of the latter to 5 of the former. Two-coat is laid with two different aggregates and gauges. The first coat has a cheap aggregate, such as ballast, clinkers, bricks, or whinstone, broken so that they will pass through a 1 inch mesh riddle, and gauged in the ratio of 1 of Port¬ land cement to 5 of the aggregate. It is laid till within 1 inch of the finished surface. The second coat is laid as soon as the first is set, and is composed of 1 part of Portland to 2 of the aggregate, the latter being either crushed granite, slag, limestone, or whinstone that will pass through a 3-16 sieve. In some districts fine shingle is used for the topping aggregate. Quick-setting solutions are used to reduce the time re¬ quired to allow the paving to harden before it is avail¬ able for traffic. Many pavements are ruined by being used before having become sufficiently hard and set. Many of the so-called quick-setting materials have the desired effect of setting the concrete quickly, but the work in many cases is none the better for these solutions. On no account should these quick-setting materials be used, unless thorougliy tested and the concrete proved durable by use and time. In order to protect the sur¬ face and allow the paving to be used immediately, P. M. Bruner, an American engineer and concrete specialist, covers the surface of the pavement directly it is finished with a thin coat of plaster or Parian cement, which ad¬ mits of walking upon in a few hours, and resists pedes- 312 CEMENTS AND CONCRETES trian traffic until the surface proper is sufficiently hard, after which it is shelled off with a trowel. Eureka Paving .—This is the name for an improved concrete, which has been extensively used with good re¬ sults for many jmrposes, such as pavements, floors and stairs. Eureka, if not exactly one-coat work, is nearer that than two-coat work, and may be said to be the happy medium, or a combination of both. Eureka is laid in two layers. The first is termed the “rough coat,” and the second the “fine coat” or “topping.” The topping is laid nearly as soon as the rough coat is laid, just as in rendering or dubbing-out plaster work. The materials and gauges are nearly alike for both layers. The gauged rough stuff is laid on the founda¬ tion, previously wetted to prevent suction, and spread and beaten with an iron hand-float. The laying, spread¬ ing and beating is continued until the rough surface is within y 2 inch of the finished line. The surface of the rough coat is made fair, and a uniform thickness for the topping is obtained by passing a “gauge-rule” across the surface. A uniform thickness of topping. gives an equal expansion, therefore the surface is not liable to crack. The suction is also more regular, which permits of the trowelling to be done with greater free¬ dom, and without causing hard and soft places on the surface. As many alternate bays are laid as will allow of all being topped and finished the same day. When the number of bays to be laid in on one day has been de¬ cided, and the last one roughened in, the first bay will be firm to receive the topping. The topping is laid and spread with a wooden hand-float, ruled and trowelled and brushed as afterwards described in the general pro - cess. This method of laying a part of the thickness of HOW TO USE THEM 313 the paving, gauging stiff and beating the mass, forces it into the interstices of the broken dry foundation, and not only consolidates the foundation and the rough coat, but also forms a solid bed to receive the topping. The topping goes in sooner and more regularly on a stiff- gauged and well-beaten coat than on a soft-gauged one, or than if the whole thickness of the paving were laid in one coat. Eureka Aggregate .—The method of preparing the ag¬ gregate for Eureka is of the utmost importance. The labor expended on its preparation is more than repaid, not only in the ease and rapidity when finishing, but also in the satisfaction of doing a strong and workmanlike job. Slag and granite is far more preferable to gravel or stone as an aggregate. Slag and granite in equal proportions have been used with good results. The size ordered from the furnace or quarry should be % inch screenings. It must be washed through a y 8 inch sieve in a tub or iron tank. The coarse part rejected by the sieve to be laid aside for the rough coat. The fine ag¬ gregate is then washed again through a fine sieve to ex¬ tract any mud or impalpable powder, as the presence of such impurities weakens the consolidating power of the cement, and decreases the ultimate strength of the con¬ crete. This fine aggregate for the topping should be angular and of various graduating sizes, from that of fine sharp sand to the largest size that has passed through the y 8 inch sieve. It has been proved by experience and the test of time that an artificial stone made with a fine aggregate has not only more resemblance to the grain or texture of natural stone, but is also denser, and wears better and with more uniformity, than one made with a large, round, or equal-sized aggregate. The use of small and angular aggregate of the graduating sizes ensures 314 CEMENTS AND CONCRETES their fitting closer and interlocking together, thus form¬ ing a stronger bond, giving a regular key and freedom for each separate piece to be coated with cement, the whole forming a solid and homogeneous body with a hard surface. Concrete with large or round aggregate, and the various pieces disproportionate in size to each other, will fit loosely and unevenly, and only touch at their most prominent points, thus leaving voids, and con¬ sequently unsound work. The voids may perchance be wholly or partly filled with matrix, still this is an un¬ necessary waste of cement. Consequently, concrete pav¬ ing having large or round aggregate weal’s unevenly, and leaves the large or round pieces uncoated and loose, or so exposed above the surface that they soon get dis¬ lodged, leaving a series of small holes, which sooner or later wear larger and larger. Another point of import¬ ance is that concrete with a fine hard aggregate is more plastic, works freer, and has a greater compressive strength than concrete with a large or soft aggregate. Eureka concrete, having a fine, clean, and regulated ag¬ gregate, should be used for the topping of paving, steps, landings, or for any class of work exposed to friction or wear. It is well to remember that a good matrix will not make a bad aggregate strong, although a bad ag¬ gregate will make a good matrix weak, or rather the re¬ sultant concrete weak. Eureka Quayitities .—The quantities for the rough coat are 1 part of Portland cement and 4 parts of the coarse portion of Eureka aggregate. These materials must be gauged stiff, only as much water being used as will allow the mass to be thoroughly mixed and plastic. The quantities for the topping are 2 parts of Portland cement to 5 of the fine aggregate, and gauged about the consistency of well-tempered “coarse stuff,” as used for HOW TO USE THEM 315 floating. Experiments prove that neat cement is infe¬ rior in wear-resisting qualities (such as frictional wear and pedestrian traffic) to mixture of cement with sand or other aggregate, being in fact equal to a mixture of about 1 part of cement to 3 parts of aggregate. The best wearing qualities are obtained by a mixture of 2 parts of cement to 3 of aggregate. Levels and Falls .—Accurate levelling and adjustment of the requisite falls are important features for pave¬ ments and flooring. Levelling is the art by which the rel¬ ative heights of any number of points are determined. Falls are used to allow rain and water used for cleansing purposes to run off into channels and drains. The levels and falls in good buildings are generally marked, on the drawings, but it is imperative that the worker should be conversant with the necessary amount of falls for paving purposes, as many unforeseen difficulties often arise in this class of work, especially in large surfaces. The most accurate and speedy way of setting out levels and falls is of special service to concrete paviors. The importance of these features will be readily appreciated, especially where these paving preliminaries are left to the care of the concrete layers. The amount of cross fall for street pavements varies according to the class and position of the work. The fall is also regulated by the gradient. For a level stretch of paving it is generally 1 to 60, therefore * for a pavement 6 feet wide it would be 1 inch. The fall for rising ground is usually % inch for every 2 feet in the width of the pavement. The falls for stables and yards are given under their respective headings. The points for levelling—also for falls—are formed by driv¬ ing wooden pegs into the ground at the most suitable points. The heads of the pegs represent the finished face of the pavement. They are made level with each other 316 CEMENTS AND CONCRETES by the aid of a parallel rule and a spirit-level. Inter¬ mediate pegs may also be levelled by means of boning rods. Pavement Foundations —Good foundations for con¬ crete paving are of primary importance, and unless the bottom is firm, and the foundation is sound, the best made and laid concrete will subside, crack, and be per¬ manently spoilt. Pavements generally cover a large area, and the superstructure, however strong, must have a firm foundation. Foundations consist of two parts— the first is the bottom ground or natural foundation; the second is the made-up or artificial foundation; but for simplicity the first is termed the “bottom,” and the lat¬ ter the “foundation.” The latter may be “dry” or “gauged.” If the bottom is soft, it must be well ram¬ med before laying the dry materials for the foundation, or a layer of common coarse concrete for gauged work. When excavating the ground to receive the foundation, the depth from the intended finished surface of the pavement should be about 5 inches for paving 2 inches thick, 6 inches deep for paving 2 y 2 inches thick, and 7 inches deep for paving 3 inches thick. The above depths are for dry foundations, and where the traffic is light, such as side-walks, playgrounds, and passages. If the bottom is soft, or the paving intended for heavy traffic, the depths may be increased, and the bottom well ram¬ med before the materials are laid. The materials for the dry foundations are broken bricks, stone rubble, or other hard core. They should be spread on the bottom, and broken in situ. The breaking in situ tends to consoli¬ date the bottom and the foundation. When broken, no piece should be left that will not pass through a 2^2 inch ring. If the paving is intended for heavy traffic (carts HOW TO USE THEM 317 or the rolling of heavy casks) it is best to have a rough concrete foundation. The rough concrete should he from 4 to 7 inches deep, according to the firmness of the bottom and class of traffic. This concrete is composed of ballast or equal parts ballast and broken bricks, coke- breeze, or hard clinkers, gauged in the proportion of 1 of Portland cement to 5 or 6 of aggregate. It should be laid to the desired fall. If lime instead of Portland ce¬ ment is used for the rough concrete, great care should be taken to thoroughly damp the surface, and allow a sufficient time for the lime to expand and any lumps of unslaked lime to slake, before the fine concrete is laid. No paving should be laid until the rough concrete is thor¬ oughly set. Allowance must also be made for any set¬ tlement of the bottom, and for any subsidence, contrac¬ tion, or expansion of the concrete foundation. The rough is not so liable to contraction or expansion as fine concrete, but it is more liable to subsidence. Expansion is due to the cement not to the aggregate; and as there is less cement in rough concrete than in fine, it has less power of expansion, and owing to the greater amount and weight of aggregate, there is the lesser power of con¬ traction. The size of aggregate for rough concrete is also larger than for fine; consequently each piece offers a greater resistance to the cement. Subsidence is due to the settlement by gravitation of the aggregate to the bot¬ tom, which takes place after the excess water, or even the liquid cement, has percolated through voids or spaces of badly made or laid concrete. Unequal subsidence is caused by bad and unequal gauging; one gauge being firm, keeps in position; while if soft and sloppy, the ex¬ cess water either settles in the deepest places, or escapes 318 CEMENTS AND CONCRETES into the ground, thus allowing the body of the concrete at those parts to subside. Screeds and Sections .—Screeds are used as guides and bearings for leveling and ruling off. They are general¬ ly formed with wood rules, planed on all sides, and in suitable sizes, and are termed “screed rules.” Screeds are sometimes formed with the same kind of material as used for the pavement, and are termed ‘ ‘ gauged screeds. ’ ’ Screed rules give the best results; they are speedily laid; can be used at once, and form a clean and square joint when laying work in sections. Screed rules are tempo¬ rarily fixed on the foundation by laying them on narrow strips of gauged concrete, and then made straight, and to the proper falls, by laying the edge of a straight-edge on them, and tapping with a hammer till firm and true. When the bay is finished and set, the screeds are re¬ moved by gently tapping with a hammer, leaving a clean, straight, and square joint. Where there is only a small quantity of screeds required, or where time will not per¬ mit of waiting for the concrete bedding strips to set, the screed rules can be fixed on gauged plaster, which al¬ lows the screeds to be used at once. The plaster should be cleaned off at the side intended to be laid, to ensure a sound bed for the concrete, and a square joint. Gauged screeds may be also formed with gauged coarse plaster. They are best done as described for “pressed screeds.” In laying large surfaces it is best to arrange the screeds, so that the work can be laid in alternate sections or bays, which will afford greater facility to get at the work, and also to allow the isolated bays to expand. For instance, if laying a stretch of paving 50 feet long and 6 feet wide, this would be laid out in 5-feet bays, the screed rules, each 6 feet long, being laid so as to form the odd num- HOW TO USE THEM 319 bered bays to be laid and finished first. This allows the workmen more freedom by standing on the empty bays when finishing the laid bay. The screeds are then re¬ moved, and the intermediate bays laid, the sides of the finished bays serving as screed or bearing when ruling in. Boards or bags are laid on the finished bays to pro¬ tect the surface, and give a footing for a workman to finish off the intermediate spaces. It must not be for¬ gotten to fix the screed rules toward the curbs, also to keep the ends of the screed about % inch about the curb, to allow for any subsidence, and for the water to run off. This also provides for the greater amount of wear Sections of Concrete Kerb, Channel, and Paving. NO. 1. that takes place near to than actually on the curb. The foundations should be thoroughly saturated with water before the screeds are fixed. If this is not done, the brick or other dry material used will absorb the moisture or life from the concrete, and render it dry or dead. The drenching with water also frees the broken materials from the dust caused by breaking the large pieces in situ. In laying paving or a gauged foundation, the sur¬ face should be well swept with a hard broom and after- 320 CEMENTS AND CONCRETES wards damped, so as to ensure the perfect cohesion and solidity of the foundation and the paving. The curbs and channels are sometimes made in situ, but more often they are cast and laid in the same manner as ordinary stone. Cast work is harder than laid work; it also al¬ lows the paving to be laid with greater freedom. Illus¬ tration No. 1 shows sections of the street curbing and channel which may be used in connection with slab pav¬ ing, or pavements laid in situ. Laying Concrete Pavements .—The foundations having been damped, and the rough stuff gauged, it is carried in pails and emptied at the top end of the bay. The plas¬ terer spreads it with a layer float, and rams it well into the foundation. When he has laid a stretch the whole width of the bay, and as far as he can conveniently reach, he moves back and lays the remaining portions of the bay in the same way until complete. The rough stuff surface is then made fair, but not smooth, with the gauge rule. The remainder of the bays are dealt with in rota¬ tion. The fine aggregate is then gauged, and laid and spread until flush with the screeds. The stuff should be rather above than below the screeds, to allow for subsi¬ dence by subsecpient ramming, ruling and patting. All concrete bodies over 2 inches thick should be deposited in layers. Each layer should be well rammed with an iron, or hardwood temp, bound with iron. Concrete gains strength by compression, and consequently its density, imperviousness, and durability are increased. Even for 2 inch pavement better results are obtained if the stuff is deposited in two layers, each layer well beaten with an iron hand-float. If only iy 2 inches thick, it should be consolidated by being beaten with an iron float. The surface is -next ruled with a floating rule. HOW TO USE THEM 321 The rule is worked square or edge, and the concrete cut and beaten in successive short and quick strokes. If the stuff is soft and laid too full, the rule is worked loosely on edge with a zigzag motion, so as to draw the excess stuff and water off the surface, and leave the body full and regular. If there are any hollow places, they are tilled up with stuff, and the rule again applied. In all cases the surface should be finally straightened by beat¬ ing with the rule. This process leaves the surface more uniform, straight, and solid than by dragging or working the rule. Trowelling Concrete .—After being ruled, and when slightly firm, the surface is beaten with a wood hand- float, which lays any irregular parts or projecting pieces of aggregate. The beating or patting is continued until the “fat” appears on the surface. It is then trowelled, or rather ironed, the trowel being worked on the flat of the blade with a circular motion. The plasterer, when trowelling off, should have a hand-float in the other hand to lean on when reaching to a far off part. The float is also useful to pat any dry parts. The surface must be finished with a semi-dry stock-brush to obtain a uniform grain. A vast amount of care is required in trowelling off. Perfection can only be attained by prac¬ tice, and a close observation of the materials, conditions, and the state of the atmosphere during the progress of the work. The best effects can only be attained by acquiring a knack of working the trowel on the flat, and by knowing when to begin and when to leave off. It is a waste of time, and the cause of an unequal surface, if the trowelling is begun before the stuff is firm; but time and labor will also be lost if the trowelling is left until the stuff is too stiff, or has nearly set, for then the sur- 322 CEMENTS AND CONCRETES face will be rough and patchy. In either instance the surface is more or less spoilt, and the ultimate appear¬ ance and hardness seriously affected. Grouting .—The use of neat cement for trowelling- off should not be resorted to (this is termed “grouting”), and is used when the surface is left till set, or when it has not been properly patted and trowelled. The ex¬ pansion of a strong and weak gauge being unequal, the result is that the surface peels, or should it adhere, it is patchy and discolored. Where grouting is unavoidable, the cement should be gauged with an equal part of fine aggregate, the aggregate being the same as used for the topping. Dusting .—Another bad process is that of sprinkling dry neat cement over a soft surface (this is termed “dusting”), and is used to absorb the moisture caused by sloppy gauging. It has drawbacks similar to grout¬ ing. If unavoidable, the cement should be mixed with fine dry aggregate in the same proportion as the topping. If the stuff were trowelled at the correct time, there would be no necessity for grouting; and if properly gauged, no need for dusting. No concrete surface can be made so solid and hard as when it is finished in one body and at one time. Temperature .—It is well known that extreme heat and cold effect the expansion and contraction of iron. These extremes have a similar effect on concrete, especially dur¬ ing the process of setting and hardening. Equality of temperature during setting is desirable. Cold and humid atmosphere retard setting; hot humidity acceler¬ ates it. Concrete laid in cold weather stands better than that laid during hot. Concrete laid in mild damp weather is better than in either extreme. During high HOW TO USE THEM 323 temperatures, the surface, when sufficiently hard, should be covered with damp deal saw-dust, old sacks, mats, or sail-cloth, and saturated at intervals with water. If the sun’s rays are hot, the surface of the work while in progress should be protected by extending tarpaulin or sail-cloths above the parts being laid. Concrete surfaces are further hardened by flooding with water, or where this is not practical, covering with wet saw-dust or sand as soon as set. Care must be taken that the saw-dust is clean and of a light color, as otherwise it will stain the work. Non-Slippery Pavements .—Concrete pavements for special purposes are rendered non-slippery by mixing y 8 inch lead cubes with the topping stuff. Lead cubes about y 2 inch square laid by hand from 1 inch to 4 inches apart in the moist concrete surface, have been used for rendering concrete surfaces non-slippery. Iron and brass filings are also used for the same purpose, and also for increasing the wear-resisting of concrete surface. Roughened, indented, grooved, and matted surfaces are also used to obtain a better foot-hold on concrete sur¬ faces. Grooved and Roughened Surfaces. —Stables, yards, &c., are grooved and channeled on the surfaces to pre¬ vent animals from slipping, and also to carry off urine or other liquids to the traps or gulleys. Indented sur¬ faces are useful on steep gradient to give a better foot¬ hold. Grooves are made with a special w r ood or iron tool, which is beaten into the surface as soon as the con¬ crete is floated. The grooves for stables are generally made about 5 inches from centre to centre, and the depth about % inch. A line is first made at the one end of the work, and the groover is then laid on this line, and beat- 324 CEMENTS AND CONCRETES en down with a hammer to the desired depth. Before it is taken off, a parallel rule is laid on the surface and against the groover, which is then taken up and laid close to the other side of the parallel rule, and beaten in as before, and so on until the whole surface is done. The width of the parallel rule is equal to the desired width between the grooves, less the width of the groover. Grooves, however long, can be made by moving the tool along, and against a long parallel rule. After stretch of grooves have been sunk, the surface is trowelled, and the indentations made true. It may be necessary to apply the groover again, and beat or work it forward and back¬ ward and further regulate their depth and straightness. They are then made smooth with a gauging trowel and finished with a damp brush, the sides of the grooves being left smooth to give a free passage for liquids. Grooves on a surface having a fall should radiate to¬ ward the deepest point. A level surface may be made to carry off the water by the indentation being formed wider and deeper towards the outlet. Street and other pavements are sometimes indented with metal rollers to give a better foot-hold. Platforms and other surfaces are sometimes made rough or indented by beating the moist concrete, with a “stamping-float.” The sole has a series of squares projecting about % inch, each square about 1 inch, and a half inch apart. Concrete surfaces are al¬ so roughened or matted by dabbing the surface as soon as trowelled with a coarse stiff whale-bone brush. Illus¬ tration No. 2 shows three designs of grooved surfaces for carriage drives, conservatories, &c. A plain border, or one with a single width of the main design, is generally formed on the sides and ends of the floor. A rough mat- HOW TO USE THEM 325 ted surface may also be obtained by pressing or beating a wet coarse sack or matting over the moist concrete. Stamped Concrete .—Various materials and methods are used for stamping or indenting concrete surfaces to obtain a better foot-hold, or to form any desired pattern. Iron stamps are generally used, but owing to their weight and rigid nature, are unsuitable for large sec- Fig. i. Fig. 2. Fig. 3. =1"" 11= kn 111 = m PIT 41 b NT 41 1= ,Hi P mi Tr 1 11= /*’ 0 f 2 3 Secli h ~ n I- ■ ~ l— I 1 -=1 tf Tie/’. Three Examples of Grooved Surfaces. NO. 2. tions. Plaster stamps are sometimes used for temporary purposes, or for small sections and quantities. Stamps for large concrete surfaces should be composed of a ma¬ terial that is easily made to the desired form durable and slightly flexible. Expansion Joints .—Compressive or flexible joints are used to allow for any expansion or contraction that may take place in a large area of concrete exposed to atmos¬ pheric changes. There are various methods in use for 326 CEMENTS AND CONCRETES the purpose. The first is to set out the area in small sections, and to lay them in alternate or isolated bays, thus giving time for their expansion before the inter¬ mediate bays are laid. This method, by dividing the area into small sections, is the best for preventing cracks, because small sections are stronger than large ones; and in the event of any subsidence in the foundation, the surface fissures are limited to the immediate joints of the section. Contraction and expansion is also less in small bodies than in larger ones. Another method of forming joints is by cutting with a wide chisel or a cutting tool before the rough concrete is set, a corresponding joint being cut in the fine concrete topping. False joints are made by indenting the top¬ ping after it is trowelled. A metal roller is used for finishing true joints and forming false joints. Frame strong enough to resist the expansion of the concrete would not only increase the density and strength of concrete paving and blocks, but also effectually prevent its cracking. Another method for forming sections in large sur¬ faces of pavement of floors to prevent cracks is effected thus:—first set out the size of proposed sections on the rough or first coat, then with a straight-edge, a wide chisel, or a cutting tool and a hammer, cut through the rough coat, so as to divide it into sections as set out. This done, insert wood strips into the cutting, keeping their top edges about % inch below the screeds or rules which represent the finished surface. The strips are made from % to 1% inches wide, 3-16 inch thick, and in suitable lengths. The width is regulated according to the thickness of the paving. For instance, for two inch paving the widths should be 1% inches. This allows HOW TO USE THEM 327 about % inches in the rough coat (with Ys inch play from the bottom), and about % inch in the topping, and Ys inch for the upper thickness of the topping to cover the top edges of the strips. After the strips are inserted the rough coat is beaten up or made good to the sides of the strips, and then the topping is laid and trowelled in the usual way. The surface joints are then made direct- -Half Plan of Coach Yard, with Section through Centre. NO. 3. ly over the strips, with the aid of a straight edge, so as to form a clean and sharp joint. As already mentioned, these strips allow for any subsequent contraction or ex¬ pansion, thus avoiding zigzag cracks; and in the event of repairs to underneath pipes, each section can be cut out and relaicl separately without injury to the adjoining sections. This process of inserting strips in the rough coat, cutting nearly through the topping, gives the same results as if the strips were laid flush with the surface of the topping, with the advantages that the surface can be more readily trowelled, and is more pleasing to the 328 CEMENTS AND CONCRETES eye, because the strips are not seen. A cutting tool is a blade of steel about 5 or 6 inches long and 4 inches wide, with a wood handle at one end. The section of the blade is well tapered, so as to obtain a sharp cutting edge, and form a wide top edge to offer a broad surface for the hammer while being beaten. Washing Yards .*—Eureka concrete being of a hard nature, and having a close and smooth surface, is well adapted as a flooring for all washing or cleaning pur¬ poses. The surface being smooth, it can in turn be read¬ ily cleaned. Illustration No. 3 shows the half plan of washing yard for washing carriages, &c. Stable Pavements .—The paving for stables, and other places for keeping animals, should be jointless, non-ab¬ sorbent, hard, and durable. Such paving must not be slippery, yet smooth enough to be easily washed, the whole laid to falls, and grooved to give an easy and ready passage for liquid manure and water when being washed. No material can so fully meet these require¬ ments as a well-made and well-laid concrete. Granite sets are hard, but slippery. Bricks are too absorbent; the urine percolates between the joints and generates ammonia and other effluvia which are detrimental to the health of the animals. (See Nos. 4 and 5.) Stables are generally laid with a fall toward the main channel. The amount of fall varies according to ideas of the horse owners. The fall adopted by the War office is 1 in 80 from the top of the manger to the main channel, and 1 to 36 from each side of the stall to the centre groove. The width of the main channels is usually set out with screed rules, which also act as screeds to work from. Channels are generally formed after the other surface is finished. Sometimes templates are fixed on the bed of HOW TO USE THEM 329 the channels, and the space filled in and ruled off with a straight-edge while the whole surface is being formed. The thickness of stable paving varies from 2 to 3U> inches, according to the class of horse. The thickness of the stalls is often decreased toward the manger. The most useful length is 2 feet 6 inches. They can be cut with a chisel as easy as cutting stone. Special slabs can be made for circular work, also with rebated sinking for metal plates, to cover coal-holes, drains, gas and water taps, &c. Concrete paving slabs are laid in precisely the same way as natural stone. -Sections of the various Parts of the Stable Floors shown on Illustration NO. 4. NO. 5. Concrete Slab Moulds .—Slab moulds are made with li/o inch boards ledged together. On this ground, wood sides and ends (each being 2^4 inches by 2 inches, or 3 inches by 3 inches, according to the desired thickness of slab) are fixed. One side and end is held in position with thumb screws, which fit into iron sockets, so that they can be unscrewed to relieve the slab when set. The bottom and the sides and ends are lined with strong iron or zinc plates. 330 CEMENTS AND CONCRETES Slab Making .—Slabs are mostly made by machinery. The materials are 1 part of Portland cement mixed dry with 2y 2 parts of crushed granite and slag in equal pro¬ portions that have been washed and passed through a ^4 inch sieve. They are thoroughly incorporated together in a horizontal cylinder worked by machinery, a mini¬ mum of water being added, and the mixing continued until the mass is well gauged. The mould, which has been previously oiled, is placed on a shaking machine known as a “trembler” or “dither,” which gives a rapid vertical jolting motion to the mould and its contents. A small portion of “slip,” that is, neat cement, is laid round the angles. The machine is then started, and the concrete laid on the mould by small shovelfuls at a time, a man with a trowel spreading it over the mould until full. The surface is then ruled off. If both sides of the slabs are required for use, the upper surface is trowelled. The whole operation of mixing, filling in, and ruling off takes about seven minutes. The filled moulds are re¬ moved and allowed to stand for about three days. The slabs are then taken out, and stacked on edge and air- dried for about five days. They are then immersed in a silicate bath for about seven days, and are afterwards taken out and stacked in the open air until it is required for use. They should not be used until three months old. Paving slabs are also made by hand, by ramming and beating the moist concrete into the mould with an iron hand-float. Powerful ramming, trituration, or vio¬ lent agitation of the gauged material in the mould, tend to consolidate concrete, and it is possible to further in¬ crease homogeneity by the use of hydraulic pressure. Induration Concrete Slabs .—The surface of concrete slabs or other work exposed to friction or wear may be HOW TO USE THEM 331 hardened by soaking in a silicate solution. Silicate of soda has a great affinity for the materials of which con¬ crete is composed, and by induration causes the surface to become hard, dense, and non-porous. The silicate of soda and potash is known as soluble glass or dissolved flint. The soluble silicate is a clear viscous substance made from pure flint and caustic soda, w r hich is digested by heat under pressure indigester. Its strength is technically known as 140 degrees, which shows. 1,700 on a hygrometer. When used as a bath for concrete, it is diluted with water, the proportion vary¬ ing from 6 to 10 parts of water to one of silicate. Con¬ crete pavements, laid in situ, may also be hardened by washing with silicate solution. They should not be sili- cated until two days after being laid, to allow the mois¬ ture to evaporate and the silicate to penetrate. Mosaic .—The art of making mosaic is at the present time scarcely within the province of plasterers, but in former times many kinds were made in situ or in slabs by plasterers. The subdivision of labor has to a great extent caused mosaic-making to be confined to special¬ ists. Concrete is still made by plasterers. A brief de¬ scription of this and other kinds may prove useful as well as interesting, especially to plasterers w r ho are in the habit of fixing tiles and working in concrete. Mosaic is the art of producing geometrical, floral, or figured de¬ signs, by the joining together of hard stones, marbles, earthenware, glass, or artificial stone, either naturally or artificially colored. The term “mosaic” embraces a wide range of artistic processes and materials for the decoration of floors, walls, ceilings. The Egyptians were experts in mosaic. The Cairo worker as a rule had no drawings made beforehand, but the mosaic design was 332 CEMENTS AND CONCRETES constructed by the artist as he arranged the pieces on the ground. The mosaic pavements of Cairo are of a slightly different character from those used for wall decoration, and are generally composed entirely of mar¬ ble tesserae (and sometimes red earthenware) of larger size than the delicate pieces included in wall mosaics. They are arranged to form geometrical patterns within a space of about two feet square. Each square slab is made separately, and the pieces are set, not in plaster, but in a composition of lime and clay impervious to water. The clay must be unburnt, just as it comes from the pit. Saracenic mosaic in Egypt is a combination of the tesselated method with a large proportion of sectile mosaic. The Romans also were great workers in mosaic. The mosaics of Byzantium and Ravenna consisted of cubes of opaque and colored glass. The general method used here for pavement mosaic is as follows: The repeated design is traced on stout paper and small pieces of marble, or more often tile, are gummed on the paper, following the design of form and color, one piece at a time (with the smooth face down¬ wards) being laid until the design is completed. The mosaic slabs, which are thus temporarily kept in posi¬ tion, are sent to the building and laid where intended. A rough concrete foundation, which has previously been made level, is then floated with Portland or Keen’s cement, and the slabs with paper are then damped and drawn off, and any openings or defects filled up with small pieces of the same form and color as the design. The slabs are made in various sizes according to the de¬ sign. For instance, a border 12 inches wide may be made from 3 to 6 inches long. When laying the slabs, it is best to begin at the centre and work outwards, and any ex- HOW TO USE THEM 333 cess or deficiency taken off or made up in the plain part of the border at the walls. The tiles are made at pottery works in the required sizes and colors. The thickness is generally about *4 inch and the average surface size about y< 2 . inch. Females are often employed fixing the pieces on the paper. The designs of coats of arms, mono¬ grams, dates, figures, flowers, and foliage are effectively produced by this simple and cheap process. Concrete Mosaic .—All mosaics are more or less of a concretive nature, and the trade term of “concrete mo¬ saic” is due to the fact that the matrix used is Portland or other cement gauged with the marble aggregate, and laid in most cases in a similar manner as ordinary con¬ crete. Concrete mosaic is extensively used for paving halls, corridors, conservatories, terraces, &c. It is also used for constructing steps, landings, baths, pedestals, &e. Slabs and tiles made of this class of mosaic for paving purposes are slowly but surely proving a for¬ midable rival to Italian mosaic encaustic tiles. It can be made in larger sections, thus facilitating rapidity of laying. It is more accurate in form, durable, non-slip- pery, and cheaper. The last reason alone is a favorable item in this keen age of competition. Where marble has been scarce, broken tiles, pottery, colored glass, flints, white spar, &c., have been used as aggregate. If the marble chips are obtainable as a waste, and near the place of manufacture, the primary cost is small. If the moulds are of metal, and made in sections so as to form a series of moulds in one case, and the casts are pressed by means of a hydraulic power, the cost of production is reduced to a minimum. If the casts are polished in large num¬ bers by machinery on a revolving table, the total cost is further reduced. For local purposes they can be made 334 CEMENTS AND CONCRETES by hand at a medium cost. Slabs are made in almost any size, blit generally from 4 to 6 feet superficial. The thickness varies from 1 to iy 2 inches. Tiles are usually made about 10 inches square and 1 inch thick. The tiles are generally made with a face of cement and white mar¬ ble, or white and black marble chippings. They are backed up with a cheaper aggregate. Various tints of the face matrix are obtained by mixing the cement with metallic ovides. The tiles are made in wood or metal moulds, with metal strips to form the divisions of form and color in the design. If the design is fret pattern, the gauged material is put in between the strips that form the band of the fret. When the stuff is nearly set, the strips are taken out, and the other part filled in with another color. Sometimes the band or running designs are cast in a separate mould, and when set placed in posi¬ tion in a larger mould, and the ground filled in, cover¬ ing and binding the whole in one tile. Another plan is to lay a thin coat of cement on the face of the mould, forming the design with small marble chips by hand, by pressing the marble into the cement as desired. When it is firm, it is backed up with the ordinary stuff, and when set, they are ground and polished. Concrete Mosaic Laid “in Situ .”—Pavements for halls, passages, shops, landings, &c., are also done in situ. A rough concrete foundation is first laid fair to falls and levels within y 2 inch of the finished surface line. This y 2 inch space is to receive the plastic marble mo¬ saic. The main or centre part is generally done first and the border last. This allows a walking space or bearing for boards, laid from side to side to work on when laying the centre. A plank sufficiently strong to keep one or two crossboards from touching the work is HOW TO USE THEM 335 laid along each side. On the side planks the crossboards are laid, and moved about when required. The width of the border is marked on the floor, and wood screed rules laid level to the marks to form a fair joint line for the border, also as a screed when floating the centre part. The screed rules are generally fixed with a gauge plaster, which is quicker than fixing on gauged cement. After the centre is laid, the plaster should be carefully swept off, and the concrete well wetted before the border is laid. The marble and cement is gauged in the proportion of 2 of marble to 1 of cement, and laid flush with screeds, laying and beating it in position with a long wood hand- float. The surface is ruled in from screed to screed with a straight-edge. The surface is then ironed with a lay¬ ing trowel until it is smooth and fair. If the marble does not show, or is not regular, or is insufficient, the bare parts are filled in with marble by hand. When marble is scarce, the *4 inch of the top surface is laid in two coats, the first being composed of cement and a cheaper aggregate, such as broken stone, tiles, &c., and gauged in the same proportion as the upper or marble coat. It is laid about ^ inch thick, and when it is firm, but not set, the marble coat is laid as before directed. The first coat saves the marble, and being firm, tends to keep the marble in the upper coat from sinking. The top coat is sometimes sprinkled over with fine marble chips by hand or through a fine sieve, then pressed into the surface and ironed with a laying trowel. Before ironing the surface, care should be taken that the chips are equally distributed, also that their flat surfaces are uppermost, and that the matrix and chips are perfectly solid and free from ridges and holes. After the centre is laid and the screeds removed, the border is laid in a 336 CEMENTS AND CONCRETES similar way. If there are two or more colors or forms in the border, the divisions are formed with narrow screed rules, and arranged so that as many as practicable can be laid at the same time. This allows the various parts to set at one time, and saves waiting for each separate part to set. The screed rules for circular work or angles are formed with strong gauged plaster and then oiled. The marble chips are either broken by hand or in a stone-breaking machine. The chips vary in size from 1-10 to inch. The best colors for borders are a black matrix with white marble or spar chips, or a white matrix with black marble chips. The white matrix is obtained by mixing the marble dust (produced when breaking the marble into chips) with a light colored Portland cement. The centres can be made in various tints, but the most general is a warm red, which is ob¬ tained by mixing the cement with red oxide. Cement colored with red oxide should be laid first, as it is liable to stain other parts of a lighter color. When the centre and border are laid, the floor is left until the whole is perfectly set and hard, and it is then fit to polish. This is done by means of a stone polisher, water and marble dust, or fine slag powder. The stone polisher is a piece of hard stone from 8 to 12 inches square, • and about 3 inches thick, into which an iron ring is inserted and se¬ cured with lead. A wooden handle from 4 to 6 feet long, with an iron hook at one end, is inserted into the ring, so that the handle is firm on the stone, yet has sufficient play to be moved freely backwards and forwards. The polishing should not be attempted until the stuff is thor¬ oughly set, because the polishing will destroy the face of the cement, and cause a vast amount of extra labor in grinding the surface down until free from holes. Small HOW TO USE THEM 337 parts of the gauged stuff should be set aside as tests for determining when the stuff is set. Concrete mosaic, where economy is desirable, will make a strong, durable, and waterproof floor, and an excellent substitute for higher class mosaics. A Bulletin (No. 235), prepared by P. S. Wormley for the U. S. government on cement, mortar, and concrete, from which I quote at length, contains some excellent in¬ formation and instructions on the preparation and the use of the above materials. This bulletin is intended for free distribution and may be obtained by making appli¬ cation to the U. S. Department of Agriculture, Wash¬ ington, D. C. Storing Cement .—In storing cement care must be ex¬ ercised to insure its being kept dry. When no house or shed is available for the purpose, a rough platform may be erected clear of the ground, on which the cement may be placed and so covered as to exclude water. When properly protected, it often improves with age. Cement is shipped in barrels or bags, the size and weight of which usually are given. Cement Mortar .—Cement mortar is an intimate mix¬ ture of cement and sand mixed with sufficient water to produce a plastic mass. The amount of water will vary according to the proportion and condition of the sand, and had best be determined independently in each case. Sand is used both for the sake of economy and to avoid cracks due to shrinkage of cement in setting. Where great strength is required, there should be at least suffi¬ cient cement to fill the voids or air spaces in the sand, and a slight excess is preferable in order to compensate for any uneven distribution in mixing. Common propor¬ tions for Portland cement mortar are 3 parts sand to 1 CEMENTS AND CONCRETES 338 of cement, and for natural cement mortar, 2 parts sand to 1 of cement. Unless otherwise stated, materials for mortar or concrete are considered to be proportioned by volume, the cement being slightly shaken in the measure used. A ‘dean” mortar is one having only a small propor¬ tion of cement, while a “rich” mixture is one with a large proportion of cement. “Neat” cement is pure cement, or that with no admixture of sand. The term ‘ ‘ aggregate ’ ’ is used to designate the coarse materials en¬ tering into concrete—usually gravel or crushed rock. The proportion in which the three elements enter into the mixture is usually expressed by three figures sepa¬ rated by dashes—as, for instance, 1-2-5, meaning 1 part cement, 2 parts sand, and 5 parts aggregate. In the great majority of cases cement mortar is subjected only to compression, and for this reason it would seem nat¬ ural that, in testing it, to determine its compressive strength. The tensile strength of cement mortar, how¬ ever, is usually determined, and from this its resistance to compression may be assumed to be from 8 to 12 times greater. A direct determination of the compressive strength is a less simple operation, for which reason the tensile test is in most cases accepted as indicating the strength of the cement. Mixing .—In mixing cement mortar it is best to use a platform of convenient size or a shallow box. First, de¬ posit the requisite amount of sand in a uniform layer, and on top of this spread the cement. These should be mixed dry with shovels or hoes, until the whole mass ex¬ hibits a uniform color. Next, form a crater of the dry mixture, and into this pour nearly the entire quantity of water required for the batch. Work the dry material HOW TO USE THEM 339 from the outside toward the centre, until all the water is taken up, then turn rapidly with shovels, adding water at the same time by sprinkling until the desired consist¬ ency is attained. It is frequently specified that the mor¬ tar shall be turned a certain number of times, but a bet¬ ter practice for securing a uniform mixture is to watch the operation and judge by the eye when the mixing has been carried far enough. In brick masonry the mis¬ take is frequently made of mixing the mortar very wet and relying upon the bricks to absorb the excess of water. It is better, however, to wet the brick thoroughly and use a stiff mortar. Grout .—The term “grout” is applied to mortar mixed with an excess of water, which gives about the consist¬ ency of cream. This material is often used to fill the voids in stone-masonry, and in brick work the inner por¬ tions of walls are frequently laid dry and grouted. The practice in either case is to be condemned, except where the conditions are unusual, as cement used in this way will never develop its full strength. Lime and Cement Mortar. —L. C. Sabin finds that in Portland cement mortar containing three parts sand to 1 of cement, 10 per cent, of the cement may be replaced by lime in the form of paste without diminishing the strength of the mortar, and at the same time rendering it more plastic. In the case of natural cement mortar, lime may be added to the extent of 20 to 25 per cent, of the cement with good results. The increased plasticity due to the addition of lime much facilitates the operation of laying bricks, and has caused lime and cement mortar to be largely used. Cement Mortar for Plastering .—In plastering with cement, a few precautions must be observed to insure 340 CEMENTS AND CONCRETES good and permanent results. The surface to receive the plaster should be rough, perfectly clean, and well satu¬ rated with water. A mortar very rich in cement is rather a drawback than otherwise on account of shrink¬ age cracks, which frequently appear. The mortar, con¬ sisting of two or three parts sand to one of cement, should be mixed with as little water as possible and well worked to produce plasticity. It is essential that the plaster be kept moist until it has thoroughly hardened. Materials for Making Concrete Sand .—In securing sand for mixing mortar or concrete, if it is possible to select from several varieties, that sand should be chosen which is composed of sharp, angular grains, varying in size from coarse to fine. Such sand is, however, not always obtainable, nor is it essential for good work. Any coarse-grained sand which is fairly clean will answer the purpose. If gravel, sticks, or leaves be present they should be removed by screening. The voids in sand vary from 30 to 40 per cent., according to the variation in size of grains. A sand with different-sized grains is to be preferred, because less cement is required to fill the voids. By mixing coarse and fine sand it is possible to reduce the voids considerably. It is customary to use the terms “river sand,” “sea sand,” or “pit sand,” according to the source of the supply. River sand as a rule has rounded grains, but unless it contains an excess of clay or other impurities, it is suitable for general purposes. When river sand is of a light color and fine-grained it answers well for plaster¬ ing. Sea sand may contain the salts found in the ocean. The tendency of these salts to attract moisture makes it HOW TO USE THEM 341 advisable to wash sea sand before using it for plastering or other work which is to be kept perfectly dry. Pit sand for the most part will be found to have sharp, angular grains, which make it excellent for mor¬ tar or concrete work. Where clay appears in pockets it is necessary either to remove it, or else see that it is thoroughly mixed with the sand. The presence of clay in excess frequently makes it necessary to wash pit sand before it is suitable for use. The results of tests made in this laboratory would in¬ dicate that the presence of clay, even in considerable amounts, is a decided benefit to “lean” mortars, whereas it does not appreciably affect the strength of a rich mixture. Gravel .—It is important that gravel for use in con¬ crete should be clean, in order that the cement may prop¬ erly adhere to it, and form a strong and compact mass. As with sand, it is well to have the pieces vary in size, thereby reducing the voids to be filled with mortar. The voids in general range from 35 to 40 per cent. Crushed Stone .-—The best stone for concrete work con¬ sists of angular pieces, varying in size and having a clean, rough surface. Some form of strong and durable rock is to be preferred, such as limestone, trap, or gran¬ ite. The total output of the crusher should be used be¬ low a maximum size, depending upon the nature of the work in hand. All material under % inch will act as so much sand and should be considered as such in propor¬ tioning the mixture. Precautions must be taken to in¬ sure a uniform distribution of the smaller pieces of stone, otherwise the concrete will have an excess of fine ma¬ terial in some parts and a deficiency in others. 342 CEMENTS AND CONCRETES Less than 8 per cent, of clay will probably not seri¬ ously impair the strength of the concrete, provided the stones are not coated with it, and may even prove a benefit in the case of lean mixtures. The voids in crushed stone depend upon the shape and variation in size of pieces, rarely falling below 40 per cent., unless much fine material is present, and in some cases reaching 50 per cent. A mixture of stone and gravel in equal parts makes an excellent aggregate for concrete. 8'tone Versus Gravel .—It would appear from tests that crushed stone makes a somewhat stronger concrete than gravel, but the latter is very extensively used with uni¬ formly good results. This superiority of stone over gravel for concrete work is attributed to the fact that the angular pieces of stone interlock more thoroughly than do the rounded pebbles, and offer a rougher surface to the cement. A point in favor of gravel concrete is that it requires less tamping to produce a compact mass than in the case of crushed stone. Then, too, the proportion of voids in stone being usually greater than in gravel, means a slight increase in the cost of concrete. Cinders .—Cinders concrete is frequently used in con¬ nection with expanded metal and other forms of rein¬ forcement for floor construction, and for this purpose it is well adapted on account of its light weight. Its poros¬ ity makes it a poor conductor of heat and permits the driving of nails. Only hard and thoroughly burned cin¬ ders should be used, and the concrete must be mixed quite soft so as to require but little tamping and to avoid crushing the cinders. Cinder concrete is much weaker, both in tension and compression, than stone or gravel concrete, and for this reason admits only of light rein¬ forcement. HOW TO USE THEM 343 Concrete .—General Discussion: Cement concrete is the product resulting from an intimate mixture of cement mortar with an aggregate of crushed stone, gravel, or similar material. The aggregate is crushed or screened to the proper size as determined from the char¬ acter of the work. In foundation work, stone or gravel 3 inches in size may be used to advantage, whereas in the case of moulded articles of small sectional area, such as fence posts, hollow building blocks, &c., it is best to use only such material as will pass a x /2 inch screen. An ideal concrete, from the standpoint of economy, would be that in which all voids in the aggregate were com¬ pletely filled with sand, and all the voids in the sand completely filled with cement, without any excess. Un¬ der these conditions there would be a thoroughly com¬ pact mass and no waste of materials. It is a simple matter to determine the voids in sand and also in the aggregate, but in mixing concrete the proportions vary a great deal, depending in each case upon the nature of the work and the strength desired. For example, in the construction of beams and floor pan¬ els, where maximum strength with minimum weight is desired, a rich concrete should be used, whereas in mas¬ sive foundation work, in which bulk or weight is the controlling factor, economy would point to a lean mix¬ ture. When good stone or gravel is used, the strength of the concrete depends upon the strength of the mortar em¬ ployed in the mixing and the proportion of mortar to aggregate. For a given mortar the concrete will be strongest when only enough mortar is used to fill the voids in the aggregate, less strength being obtained by using either greater or less proportion. In practice it is 344 CEMENTS AND CONCRETES usual to add a slight excess of mortar over that required to fill the voids in the aggregate. It is more accurate to measure cement by weight un¬ less the unit employed be the barrel or sack, because when taken from the original package and measured in bulk there is a chance of error due to the amount of shaking the cement receives. As it is less convenient, however, to weigh the cement, it is more usual to measure it by volume, but for the reasons stated this should be done with care. Proportioning Materials .—For an accurate determina¬ tion of the best and most economical proportions where maximum strength is required, it is well to proceed in the following way: First, proportion the cement and sand so that the cement paste will be 100 per cent, in ex¬ cess of the voids in sand; next, determine the voids in the aggregate and allow sufficient mortar to fill all voids, with an excess of 10 per cent. To determine roughly the voids in gravel or crushed stone prepare a water-tight box of convenient size and fill with the material to be tested, shake well and smooth off even with the top. Into this pour water until it rises flush with the surface. The volume of water added, divided by the volume of the box, measured in the same units, represents the proportion of voids. The propor¬ tion of voids in sand may be more accurately determined by subtracting the weight of a cubic foot of packed sand from 165, the weight of a cubic foot of quartz, and divid¬ ing the difference by 165 degrees. The following will serve as an example of proportion¬ ing materials: Assume voids in packed sand to measure 38 per cent., and voids in packed stone to measure 48 per cent. Cement paste required per cubic foot of sand, HOW TO USE THEM 345 0.38 and 1-10 equals 0.42 cubic foot, approximately. By trial, 1 cubic foot of loose cement, lightly shaken, makes 0.85 cubic foot of cement paste, and requires or 2 cubic feet of sand, approximately, producing an amount of mortar equal to 0.85 and 2 (1-0.38) equals 2.09 cubic feet. Mortar required per cubic foot of stone equals 0.48, and 1-10x0.48 equals 0.528 cubic foot. There¬ fore 2.09 cubic feet mortar will require equals 4 cubic feet of stone, approximately. The proportions are therefore 1 part cement, 2 parts sand, 4 parts stone. Although such a determination is usually considered un¬ necessary in practical work, it may be of sufficient inter¬ est to justify giving it. For general use the following mixtures are recom¬ mended : 1 cement, 2 sand, 4 aggregate, for very strong and impervious; 1 cement, 2 y 2 sand, 5 aggregate, for ordinary work requiring moderate strength; 1 cement, 3 sand, 6 aggregate, for work where strength is of minor importance. Aggregate Containing Fine Material .—In the case of gravel containing sand, or crushed stone from which the small articles have not been removed by screening, the amount of such fine sand or fine stone should be deter¬ mined and due allowance made for it in proportioning the mortar. When mixing an aggregate containing small particles with mortar, and in reality we have a mortar containing a larger proportion of sand than was present before the aggregate was incorporated. It is evident, then, that in such cases the quality of richness of the mortar should depend upon the proportion of fine material in the ag¬ gregate. 346 CEMENTS AND CONCRETES For example, suppose that 1 cubic foot of gravel con¬ tains 0.1 cubic foot of sand, and that the voids in gravel with sand screened out measure 40 per cent. For gen¬ eral purposes this would suggest a 1-2-5 mixture, but since each cubic foot contains 0.1 cubic foot sand, 5 cubic feet gravel will contain 0.5 cubic foot sand, and the proportions should be changed to 1 part cement, iy 2 parts sand, 5 parts gravel. Mechanical Mixers .—It has been demonstrated that concrete can be mixed by machinery as well, if not bet¬ ter, than by hand. Moreover, if large quantities of con¬ crete are required, a mechanical mixer introduces marked economy in the cost of construction. None of the various forms of mechanical mixers will be described here, since concrete in small quantities, as would be used on the farm, is more economically mixed by hand. Mixing by Hand .—In mixing by hand a platform is constructed as near the work as is practicable, the sand and aggregate being dumped in piles at the side. If the work is to be continuous, this platform should be of suf¬ ficient size to accommodate two batches, so that one batch can be mixed as the other is being deposited. The ce¬ ment must be kept under cover and well protected from moisture. A convenient way of measuring the materials is by means of a bottomless box or frame made to hold the exact quantities needed for a batch. A very common and satisfactory method of mixing concrete is as follows: First measure the sand and ce¬ ment required for a batch and mix these into mortar as described on page 5. Spread out this mortar in a thin layer and on top of it spread the aggregate, which has been previously measured and well wetted. The mixing is done by turning with shovels three or more times, as HOW TO USE THEM 347 may be found necessary to produce a thoroughly uni¬ form mixture, water being added if necessary to give the proper consistency. The mixers, two or four in num¬ ber, according to the size of the batch, face each other and shovel to right and left, forming two piles, after which the material is turned back into a pile at the cen¬ tre. By giving the shovel a slight twist, the material is scattered in leaving it and the efficiency of the mixing is much increased. Consistency of Concrete .—A dry mixture, from which water can be brought to the surface only by vigorous tamping, is probably the strongest, but for the sake of economy, and to insure a dense concrete well filling the moulds a moderately soft mixture is recommended for ordinary purposes. Where the pieces to be moulded are thin, and where small reinforcing metal rods are placed close together or near the surface, a rather wet mixture may be necessary to insure the moulds being well filled. Use of Quick-Setting Cement .—In the manufacture of such articles as pipe, fence posts, and hollow blocks, a rather large proportion of quick-setting cement is sometimes used, the object being to reduce the weight and consequent freight charges by means of a strong mixture, as well as to make the concrete impervious to water. The use of a quick-setting cement permits the moulds to be removed sooner than would be possible with a slow-setting cement, thus reducing the number of moulds necessary for a given output. Quick-setting ce¬ ments are not recommended for such purposes, however, as they are usually inferior to those which set slowly. Coloring Cement Work .—In coloring cement work the best results are obtained by the use of mineral pig¬ ment. The coloring matter, in proportions depending 348 CEMENTS AND CONCRETES upon the desired shade, should be thoroughly mixed with the dry cement before making the mortar. By prepar¬ ing small specimens of the mortar and noting the color after drying, the proper proportions may be determined. For gray or black, use lampblack. For yellow or buff, use yellow ochre. For brown, use umber. For red, use Venetian red. For blue, use ultramarine. Depositing Concrete .—Concrete should be deposited in layers of from 4 to 8 inches and thoroughly tamped before it begins to harden. The tamping required will depend upon the consistency of the mixture. If mixed very dry it must be vigorously rammed to produce a dense mass, but as the proportion of water increases less tamping will be found necessary. Concrete should not be dumped in place from a height of more than 4 feet, unless it is again mixed at the bottom. A wooden in¬ cline may be used for greater heights. Rammers for ordinary concrete work should weigh from 20 to 30 pounds and have a face not exceeding 6 inches square. A smaller face than this is often desirable, but a larger one will be less effective in consolidating the mass. In cramped situations special forms must be employed to suit the particular conditions. When a thickness of more than one layer is required, as in foundation work, two or more layers may be worked at the same time, each layer slightly in advance of the one next above it and all being allowed to set together. At the end of a day there is usually left a layer partially completed which must be finished the next day. This layer should not be beveled off, but the last batch of concrete should be tamped behind a vertical board forming a step. HOW TO USE THEM 349 To avoid introducing a plane of weakness where fresh concrete is deposited upon that which has already set, certain precautions have to be observed. The surface of the old work should be clean and wet before fresh ma¬ terial is put on, a thin coat of neat cement grout being sometimes employed to insure a good bond. The sur¬ face of the concrete to receive an additional layer must not be finished olf smoothly, but should offer a rough surface to bond with the next layer. This may be done by roughing the surface while soft with pick and shovel, or the concrete may be so rammed as to present a rough and uneven surface. Wooden blocks or scantling are sometimes embedded several inches in the work and re¬ moved before the concrete hardens, thus forming holes or grooves to be filled by the next layer. Retempering .—As stated before, it is important that concrete be tamped in place before it begins to harden, and for this reason it is proper to mix only so much at a time as is required for immediate use. The retempering of concrete which has begun to set is a point over which there is much controversy. From tests made in this laboratory it would appear that such concrete suffers but little loss of strength if thoroughly mixed with sufficient water to restore normal consistence. The time required for concrete to set depends upon the character of the cement, upon the amount and tem¬ perature of the water used in mixing, and upon the temperature of the air. Concrete mixed dry sets more quickly than if mixed wet, and the time required for setting decreases as the temperature of the water rises. Warm air also hastens the setting. Concrete Exposed to Sea-Water .—Portland cement concrete is well adapted for work exposed to sea-water, 350 CEMENTS AND CONCRETES but when used for this purpose it should be mixed with fresh water. The concrete must be practically imper¬ vious, at least on the surfaces, and to accomplish this purpose the materials should be carefully proportioned and thoroughly mixed. It is also of great importance that the concrete be well compacted by tamping, par¬ ticularly on exposed surfaces. Concrete Work in Freezing Weather .—Although it is advisable under ordinary conditions to discontinue ce¬ ment work in freezing weather, Portland cement may be used without serious difficulty by taking a few simple precautions. As little water as possible should be used in mixing, to hasten the setting of the concrete. To prevent freezing, hot water is frequently used in mixing mortar or concrete, and with the same object in view salt is added in amounts depending upon the degree of cold. A common practice is to add 1 pound of salt to 18 gal¬ lons of water, with the addition of 1 oz. of salt for each degree below 32° F. Either of the above methods Mull give good results, but it should be remembered that the addition of salt often produces efflorescence. It seems to be a fairly well-established fact that concrete de¬ posited in freezing weather will ultimately develop full strength, showing no injury due to the low temperature. Bubble Concrete .—In massive concrete work consider¬ able economy may often be introduced by the use of large stones in the body of the work, but only in heavy foundations, retaining walls, and similar structures should this form of construction be permitted. In plac¬ ing these large stones in the work the greatest care must be exercised to insure each being well bedded, and the concrete must be thoroughly tamped around them. Each HOW TO USE THEM 351 stone should be at least 4 inches from its neighbor and an equal distance from the face of the work. To Face Concrete .—A coating of mortar one-half inch in thickness is frequently placed next the form to prevent the stone or gravel from showing and to give a smooth and impervious surface. If in preparing this mortar finely crushed stone is used instead of sand, the NO, 6. work will more nearly resemble natural stone. A common method employed in facing concrete is to pro¬ vide a piece of thin sheet metal of convenient length and about 8 to 10 inches wide. To this pieces of angle iron are riveted, so that when placed next to the mould a narrow space is formed in which the cement mortar is placed after the concrete has been deposited behind it. (No. 6.) The metal plate is then withdrawn and the 352 CEMENTS AND CONCRETES concrete well tamped. The concrete and facing mor¬ tar must be put in at the same time so that they will set together. If the concrete is fairly rich, a smooth surface can usually be produced without a facing of mortar by working a spade up and down between the concrete and inner face of the mould, thus forcing the larger pieces of the aggregate back from the surface. Wood for Forms .—Lumber used in making forms for concrete should be dressed on one side and both edges. The expansion and distortion of the wood due to the absorption of water from the concrete frequently make it difficult to produce an even surface on the work, and unless the forms are accurately fitted together more or less water will find its way out through the cracks, carrying some of the cement with it. A method some¬ times adopted to minimize the effect of expansion is to bevel one edge of each board, allowing this edge to crush against the square edge of the adjacent board when expansion takes place. In the case of a wooden core or inside mold, expansion must always be taken into consideration, for if neglected it may cause cracks or complete rupture of the concrete. Sharp edges in con¬ crete are easily chipped and should be avoided by plac¬ ing triangular strips to the corners of moulds. To pre¬ vent cement from sticking to the forms they may be given a coating of soft soap or be lined with paper. This greatly facilitates their removal and enables them to be used again with but little scraping. A wire brush answers best for cleaning the forms. Concrete Sidewalks .—A useful and comparatively simple application of concrete is in the construction of sidewalks, for which purpose it has been used with marked success for a number of years. HOW TO USE THEM 353 Excavation and Preparation of Sub grade .—The ground is excavated to subgrade and well consolidated by ramming to prepare it for the subfoundation of stone, gravel or cinders. The depth of excavation will depend upon the climate and nature of the ground, being deeper in localities where heavy frosts occur or where the ground is soft than in climates where there are no frosts. In the former case the excavation should be carried to a depth of 12 inches, whereas in the latter from 4 to 6 inches will be sufficient. No roots of trees should be left above the subgrade. The Subfoundation .—The foundation consists of a layer of loose material, such as broken stone, gravel, or cinders, spread over the subgrade and well tamped to secure a firm base for the main foundation of concrete which is placed on top. It is most important that the sub foundation be well drained to prevent the accumula¬ tion of water, which, upon freezing, would lift and crack the walk. For this purpose it is well to provide drain tile at suitable points to carry off any water which may collect under the concrete. An average thickness for subfoundation is 4 to 6 inches, although in warm cli¬ mates, if the ground is firm and well drained, the sub¬ foundation may only be 2 to 3 inches thick or omitted altogether. The Foundation .—The foundation consists of a layer of concrete deposited on the subfoundation and carry¬ ing a surface layer or wearing coat of cement mortar. If the ground is firm and the subfoundation well rammed in place and properly drained, great strength will not be required of the concrete, which may, in such cases, be mixed in about the proportions 1-3-6, and a depth of only 3 to 4 inches will be required. Portland cement should 354 CEMENTS AND CONCRETES be used and stone or gravel under 1 inch in size, the con¬ crete being mixed of medium consistency, so that moisture will show on the surface without excessive tamping. The Top Dressing or Wearing Surface .—To give a neat appearance to the finished walk, a top dressing of cement mortar is spread over the concrete, well worked in, and brought to a perfectly smooth surface with straightedge and float. This mortar should be mixed in the proportion 1 part cement to 2 parts sand, sharp coarse sand or screenings below one-fourth inch of some hard, tough rock being used. The practice of making the concrete of natural cement and. the wearing surface of Portland is not to be commended, owing to a tendency for the two to separate. Details of Construction .—A cord stretched between stakes will serve as a guide in excavating, after which the bottom of the trench is well consolidated by ram¬ ming; any loose material below subgrade is then spread over the bottom of the trench to the desired thickness and thoroughly compacted. Next, stakes are driven along the sides of the walk; spaced 4 to 6 feet apart, and their tops made even with the finished surface of the walk, which should have a transverse slope of one-fourth inch to the foot for drainage. Wooden strips at least 1 y 2 inches thick and of a suitable depth are nailed to these stakes to serve as a mould to concrete. By carefully adjusting these strips to the exact height of the stakes they may be used as guides for the straight¬ edge in levelling off the concrete and wearing surface. The subfoundation is well sprinkled to receive the con¬ crete, which is deposited in the usual manner, well tamped behind a board set vertically across the trench, HOW TO USE THEM 355 and levelled off with a straightedge as shown in Fig. 7, leaving one-lialf to 1 inch for the wearing surface. Three-eighths inch sand joints are provided at intervals of 6 to 8 feet to prevent expansion cracks, or, in case of settlement, to confine the cracks to these joints. This is dene either by depositing the concrete in sections, or by dividing it into such sections with a spade when soft and filling the joints with sand. The location of each joint is marked on a wooden frame for future reference. NO. 7. Care must be exercised to prevent sand or any other material from being dropped on the concrete, and thus preventing a proper union with the wearing surface. No section should be left partially completed to be finished with the next batch or left until the next day. Any c n- crete left after the completion of a section should be mixed with the next batch. It is of the utmost importance to follow up closely the concrete work with the top dressing in order that the 356 CEMENTS AND CONCRETES two may set together. This top dressing should be worked well over the concrete with a trowel, and levelled with a straightedge (No. 7) to secure an even surface. Upon the thoroughness of this operation often depends the success or failure of the walk, since a good bond be¬ tween the wearing surface and concrete base is absolute¬ ly essential. The mortar should be mixed rather stiff. As soon as the film of water begins to leave the surface, a wooden float is used, followed up by a plasterer’s trowel, the operation being similar to that of plastering a wall. The floating, though necessary to give a smooth surface, will, if continued too long, bring a thin layer of neat cement to the surface and probably cause the walk to crack. Jointer used in dividing walk into sections. NO. 8. The surface is now divided into sections by cutting en¬ tirely through, exactly over the joints in the concrete. This is done with a trowel guided by a straightedge, after which the edges are rounded off with a special tool called a jointer, having a thin shallow tongue (No. 8). These sections may be subdivided in any manner desired for the sake of appearance. A special tool called an edger (No. 9) is run round the outside of the walk next to the mould, giving it a neat rounded edge. A toothed roller (No. 10) having small HOW TO USE THEM 357 projections on its face is frequently used to produce slight indentations on the surface, adding somewhat to Tool used in rounding edges. NO. 9. the appearance of the walk. The completed work must be protected from the sun and kept moist by sprinkling -Roller used in finishing surface NO. 10. for several days. In freezing weather the same precau¬ tions should be taken as in other classes of concrete work. 358 CEMENTS AND CONCRETES Concrete Basement Floors .—Basement floors in dwell¬ ing houses as a rule require only a moderate degree of strength, although in eases of very wet basements, where water pressure from beneath has to be resisted, greater strength is required than would otherwise be necessary. The subfoundation should be well drained, sometimes re¬ quiring the use of tile for carrying off the w r ater. The rules given for constructing concrete sidewalks apply equally well to basement floors. The thickness of the concrete foundation is usually from 3 to 5 inches, ac¬ cording to the strength desired, and for average w r ork a 1-3-6 mixture is sufficiently rich. Expansion joints are frequently omitted, since the temperature variation is less than in outside work, but since this omission fre¬ quently gives rise to unsightly cracks, their use is recom¬ mended in all cases. It will usually be sufficient to divide a room of moderate size into four equal sections, separated by y 2 inch sand joints. The floor should be given a slight slope toward the center or one corner, with provision at the lowest point for carrying off any water that may accumulate. Concrete Stable Floors and Driveways .—Concrete stable floors and driveways are constructed in the same general w r ay as basement floors and sidewalks, but with a thicker foundation, on account of the greater strength required. The foundation may well be 6 inches thick, with a 10 inch wearing surface. An objection often sometimes raised against concrete driveways is that they become slippery when wet; but this fault is in a great measure overcome by dividing the wearing surface into small squares about 4 inches on the side, by means of tri¬ angular grooves % of an inch deep. This gives a very HOW TO USE THEM 359 neat appearance and furnishes a good foothold for horses. Concrete Steps .—Concrete may be advantageously used in the construction of steps, particularly in damp places, such as areaways and cellars of houses, and in the open, where the ground is terraced, concrete steps and walks can be made exceedingly attractive. Where the ground is firm it may be cut away as nearly as pas¬ sible in the form of steps, with each step left two or three inches below its finished level. The steps are formed, beginning at the top, by depositing the con- NO. 11. Crete behind vertical boards so placed as to give the nec¬ essary thickness to the risers and projecting high enough to serve as a guide in leveling off the tread. Such steps may be reinforced where greater strength is desired or where there is danger of cracking, due to the settlement of the ground. Where the nature of the ground will not admit of its being cut away in the form of steps, the risers are 360 CEMENTS AND CONCRETES molded between two vertical forms. The front one may be a smooth board, but the other should be a piece of thin sheet metal, which is more easily removed after the earth has been tamped in behind i-t. A simple method of reinforcing steps is to place a y 2 inch steel rod in each corner, and thread these with % inch rods bent to the shape of the steps, as shown in No. 11, the latter being placed about 2 feet apart. For this class of work a rich Portland cement concrete is recommended, with the use of stone or gravel under y 2 inch in size. Steps may be given a y 2 inch wearing surface of cement mortar mixed in the proportion of 1 part cement to 2 parts sand. This system, as well as many others, is well adapted for stair¬ ways in houses. Reinforced Concrete Fence Posts .—Comparison of dif¬ ferent Post Materials: There is a constantly increasing demand for some form of fence posts which is not sub¬ ject to decay. The life of wooden posts is very limited, and the scarcity of suitable timber in many localities has made it imperative to find a substitute. A fence post, to prove thoroughly satisfactory, must fulfil three conditions: (1) It must be obtainable cost; (2) it must possess sufficient strength to meet the demands of gen¬ eral farm use; (3) it must not be subject to decay, and must be able to withstand successfully the effects of water, frost and fire. Although iron posts of various designs are frequently used for ornamental purposes, their adoption for general farm use is prohibited by their excessive cost. Then, too, iron posts exposed to the weather are subject to corrosion, to prevent which neces¬ sitates repainting from time to time, and this item will entail considerable expense in cases where a large num¬ ber of posts are to be used. HOW TO USE THEM 361 At the present time the material which seems most nearly to meet these requirements is reinforced con¬ crete. The idea of constructing fence posts of concrete reinforced with iron or steel is by no means a new one, but, on the contrary, such posts have been experimented with for years, and a great number of patents have been issued covering many of the possible forms of reinforce¬ ment. It is frequently stated that a reinforced con¬ crete post can be made and put in the ground for the same price as a wooden post. Of course this will de¬ pend in any locality upon the relative value of wood and the various materials which go to make up the concrete post, but in the great majority of cases wood will prove the cheaper material in regard to first cost. On the other hand, a concrete post will last indefinitely, its strength increasing with age, whereas the wooden post must be replaced at short intervals, probably making it more expensive in the long run. In regard to strength, it must be borne in mind that it is not practicable to make concrete fence posts as strong as wooden posts of the same size; but since wooden posts, as a rule, are many times stronger than is neces¬ sary, this difference in strength should not condemn the use of reinforced concrete for this purpose. Moreover, strength in many cases is of little importance, the fence being used only as a dividing line, and in such cases small concrete posts provide ample strength and present a very uniform and neat appearance. In any case, to. enable concrete posts to withstand the loads they are called upon to carry, sufficient strength may be secured by means of reinforcement, and where great strength is required this may be obtained by using a larger post with a greater proportion of metal and well braced, as 362 CEMENTS AND CONCRETES is usual in such cases. In point of durability, concrete is unsurpassed by any material of construction. It offers a perfect protection to the metal reinforcement and is not itself affected by exposure, so that a post constructed of concrete reinforced with steel will last indefinitely and require no attention in the way of repairs. Reinforcement .—No form of wooden reinforcement, either on the surface or within the post, can be' recom¬ mended. If on the surface, the wood will soon decay, and if a wooden core is used it will, in all probability, swell by the absorption of moisture and crack the post. The use of galvanized w T ire is sometimes advocated, but if the post is properly constructed and a gocd concrete used, this precaution against rust will be unnecessary, since it has been fully demonstrated by repeated tests that concrete protects steel perfectly from rust. If plain, smooth wire or rods are used for reinforcement they should be bent over at the ends or looped to pre¬ vent slipping in the concrete. Twisted fence wire may usually be obtained at a reasonable cost and is very well suited for this purpose. Barbed wire has been proposed and is sometimes used, although the barbs make it ex¬ tremely difficult to handle. For the sake of economy the smallest amount of metal consistent with the desired strength must be used, and this requirement makes it necessary to place the reinforcement near the surface, where its strength is utilized to greatest advantage, with only enough concrete on the outside to form a protective covering. A reinforcing member in each corner of the post is probably the most efficient arrangement. Concrete for Fence Posts .—The concrete should be mixed with Portland cement in about the proportions l-2 1 /2-5, broken stone or gravel under y 2 inch being used. HOW TO USE THEM 363 In cases where the aggregate contains pieces smaller than 14 inch, less sand may be used, and in some cases it may be omitted altogether. A mixture pf medium con¬ sistency is recommended on the ground that it fills the molds better and with less tamping than if mixed quite dry. Molds for Fence Posts .—Economy points to the use of a tapering post, which, fortunately, offers no diffi¬ culties in the way of molding. All things considered, Wooden mol d for making fence poets with four tapering sides. NO. 12. wooden molds will be found most suitable. They can easily and quickly be made in any desired form and size. Posts may be molded either in a vertical or horizontal position, the latter being the simpler and better method. If molded vertically a wet mixture is necessary, requir¬ ing a longer time to set, with the consequent delay in removing the molds. No. 12 shows a simple mold, which has been used with satisfactory results in this laboratory. 364 CEMENTS AND CONCRETES This mold lias a capacity of four posts, but larger molds could easily be made on the same principle. It consists of two end pieces, (a) carrying lugs, (b) between which are inserted strips (c). The several parts are held to¬ gether with hooks and eyes, as shown in No. 12. To pre¬ vent any bulging of the side strips they are braced, as illustrated. Dressed lumber at least 1 inch thick, and preferably iy 2 inches, should be used. In No. 12 the ,Wooden mold for making fence poata with two tapering eldea. NO. 13. post measures 6 by 6 inches at the bottom, 6 by 3 at the top, and 7 feet in length, having two parallel sides. If it is desired to have the posts square at both ends the mold must be arranged as in No. 13. This latter form of post is not as strong as the former, but requires less concrete in its construction. Great care in tamping is necessary to insure the corners of the mold being well HOW TO USE THEM 365 filled, and if this detail is not carefully watched, the metal, being exposed in places, will be subject to rust. Attaching Fence Wires to Posts .—Various devices have been suggested for attaching fence wires to the posts, the object of each being to secure a simple and permanent fastener or one admitting of easy renewal at any time. Probably nothing will answer the purpose better than a long staple or bent wire well embedded in the concrete, being twisted or bent at the end to prevent extraction. Galvanized metal must be used for fasteners, since they Detail showing method of at« (aching wire to post. NO. 14. are not protected by the concrete. A piece of small flex¬ ible wire, about two inches in length, threading the staph and twisted several times with a pair of pliers, holds the line wire in position. (No. 14.) Molding and Curing Posts .—For the proper method of mixing concrete see previous pages. It is recommended that only so much concrete be mixed at one time as can "be used before it begins to harden; but if an unavoidable delay prevents the posts being molded until after the 366 CEMENTS AND CONCRETES concrete has begun to set, it is thought that a thorough regauging with sufficient water to restore normal con¬ sistency will prevent any appreciable loss of strength, though the concrete may have been standing one or two hours. In using a mold similar to those illustrated in Nos. 12 and 13 it is necessary to provide a perfectly smooth and even platform of a size depending upon the number of posts to be molded. A cement floor if accessi¬ ble may be used to advantage. The moldis when in place are given a thin coating of soft soap, the platform or cement floor, serving as bottom of mold, being treated in the same way. About iy 2 inches is spread evenly over / the bottom and carefully tamped, so as to reduce it to a thickness of about 1 inch. A piece of board cut as in No. 12 will be found useful in leveling off the concrete to the desired thickness before tamping. On top of this layer two reinforcing members are placed about 1 inch from the sides of the mold. The molds are then filled * and tamped in thin layers to the level of the other two reinforcing members, the fasteners for fence wires being inserted during the operation. These reinforcing mem¬ bers are adjusted as were the first two, and the remain¬ ing 1 inch of concrete tamped and leveled off, thus com¬ pleting the post so far as molding is concerned. To avoid sharp edges, which are easily chipped, triangular strips may be placed in the bottom of mold along the sides, and when the molds have been filled and tamped, similar strips may be inserted on top. The top edges may be beveled with a trowel or by running an edging tool hav¬ ing a triangular projection on its bottom along the edges. Such a tool is shown in No. 15, and can easily be made of wood or metal. It is not necessary to carry the bevel* below the ground line. HOW TO USE THEM 367 The ends and sides of the mold may he removed after twenty-four hours, but the posts should not be handled for at least one week, during which time they must be well sprinkled several times daily and protected from sun and wind. The intermediate strips may be carefully withdrawn at the end of two or three days, but it is bet¬ ter to leave them in place until the posts are removed. Although a post may be hard and apparently strong when one week old^ it will not attain its full strength in that length of time, and must be handled with the utmost care to prevent injury. Carelessness in handling green posts frequently results in the formation of fine cracks, which though unnoticed at the time, give evidence of their presence later in the failure of the posts. Tool used for beveling edges of posts. NO. 15. Posts should be allowed to cure for at least sixty days before being placed in the ground, and for this purpose it is recommended that when moved from the molding- platform they be placed upon a smooth bed of moist sand and protected from the sun until thoroughly cured. Dur¬ ing this period they should receive a thorough drench¬ ing at least once a day. 368 CEMENTS AND CONCRETES The life of the molds will depend upon the care with which they are handled. A coating of mineral oil or shellac may be used instead of soap to prevent the cement from sticking to the forms. As soon as the molds are removed they should be cleaned with a wire brush before being used again. The cost of reinforced concrete fence posts depends in each case upon the cost of labor and materials, and must necessarily vary in different localities. An esti¬ mate in any particular case can be made as follows: One cubic yard of concrete will make twenty posts measuring 6 inches by 6 inches at the bottom, 6 inches by 3 inches at the top, and 7 feet long, and if mixed in the propor¬ tions l-2y 2 -5, requires approximately: 1.16 barrels of cement, at $2..$2.32 0.44 cubic yard of sand, at 75 cts...33 0.88 cubic yard of gravel, at 75 cts...66 Materials for 1 cubic yard cement.$3.21 Concrete for one post.17 28 feet of 0.16 inch steel wire, at 3 cts a pound.06 Total cost of concrete arfd metal for 1 post.23 To this must be added the cost of mixing concrete, molding and handling posts, and the costs of molds, an addition which should not in any case exceed 7 cents, making a total of 30 cents per post. Concrete Building Blocks .—Concrete building blocks, or cement blocks, as they are frequently called, are more extensively used now than ever before. These blocks are molded hollow primarily to reduce their cost, but this hollow construction serves other useful purposes at the same time. The fundamental principles governing HOW TO USE THEM 369 ordinary concrete work, so far as proportioning and mixing materials is concerned, apply equally well to the manufacture of building blocks, and it should be borne in mind that strength and durability can not be obtained by the use of any machine unless the cement, sand, and aggregate are of good quality, properly proportioned and well mixed. The aggregate for blocks of ordinary size should be crushed stone or gravel not larger than y 2 inch. One of the chief causes of complaint against the concrete building block is its porosity, but this defect is in a great measure due to the fact that in an endeavor to economize too little cement is frequently used. It is not unusual to give the blocks a facing of cement mor¬ tar consisting of about 2 parts sand to 1 of cement, while the body of the block is composed of a concrete of suffi¬ cient strength, though not impervious. This outside layer of mortar adds practically nothing to the strength of the block, and is used simply to give a uniform sur¬ face and to render the face of the wall more clearly im¬ pervious to water. It would not be practicable as a rule to attempt the manufacture of concrete blocks without one of the many forms of molding machines designed for the purpose, noi would it be economical to purchase such a machine un¬ less a sufficient number of blocks were required to justify such an outlay. Blocks in almost any desired shape and size, with either plain or ornamental faces, may be ob¬ tained on the market, and in the great majority of cases it is best to buy them from some reliable firm. Among the advantages claimed for hollow concrete block con¬ struction may be mentioned the following: (1) Hollow block construction introduces a saving of material over brick or stone masonry. 370 CEMENTS AND CONCRETES (2) The cost of laying concrete blocks is less than for brick work. This is due to the fact that the blocks, being larger, require a much smaller number of joints and less mortar, and, being hollow, are of less weight than solid brick work. (3) A wall constructed of good concrete blocks is as strong or stronger than a brick wall of equal thickness. (4) Concrete blocks, being easily molded to any de¬ sired form, will prove to be a far more economical build¬ ing material than stone, which has to be dressed to shape. (5) Experience has proved concrete to be a most ex¬ cellent fire resisting material. (6) Concrete blocks, being hollow, tend to prevent sudden changes of temperature within a house, making it cool in summer and easily heated in winter. (7) The hollow spaces provide an easy means for running pipes and electric wires. These spaces may also be used wholly or in part for heating and ventilating flues. Tests of Concrete Fence Posts .—In the summer of 1904 a number of reinforced concrete fence posts were made for experimental purposes, with a view to deter¬ mining their adaptability for general use. These posts were made both with and without reinforcement, and tested at the age of 90 days. The reinforcement, rang¬ ing from 0.27 per cent, to 1.13 per cent., consisted of four round steel rods, one in each corner of post about 1 inch from surface, the posts having a uniform cross- section of 6 by 6 inches. The posts were molded in a horizontal position, as this was found by trial to be more satisfactory than molding them vertically. HOW TO USE THEM 371 The concrete was mixed moderately soft, crushed stone between 1 inch and inch and gravel under % inch being used as aggregate. River sand, fairly clean and sharp, was employed with Portland cement. The posts were tested as beams, supported at both ends and loaded at the centre, with spans varying from 4 feet to 5 feet G inches. An attempt was made to prevent slipping by providing the reinforcing rods with collars and set screws at the ends, but in every case, with but two ex¬ ceptions, the rods slipped under a comparatively light load, thus showing the necessity for some form of me¬ chanical bond. As would be expected, those posts which were not reinforced possessed very little strength. Method of testing posts uitder static loads. A series of tests was made with sheet-iron reinforce¬ ment, in the form of round and square pipes, embedded in the posts, but these posts, though developing consid¬ erable strength, proved less economical than those rein¬ forced with plain rods, and at the same time were less simple in construction. The results of these tests, as re¬ corded in Table I., do not properly represent the strength of similar posts in which some form of mechanical bond is provided to develop the full strength of the reinforce¬ ment. TABLE 1.—Showing Results oe Preliminary Tests of Reinforced Concrete Fence Posts. 372 CEMENTS AND CONCRETES Equivalent Maximum Load on 4-foot Cantilever. 00 , 3 o 50 CcCQiCOW«OCO»CC^OOa 50 HrN|^MCO»OQif:C'liCCDH £iooa 50 oi>ioC © COC.iOCCNf ^ h a 5 h h p h oi h g r-T rH rH |H rH rH rH rH rH rH rH rH rH rH CM CM CM~ CM~ (N rH 'OT3 r O'O r O G'O'O'Q'O > r D f O'D C'C'V'V'O'O ^ O^C o c3n ro GO :o • GO :o .GO :o • GO :o a> M M a lOiOI^iOiOiOJCiCiCiOiCiOiOiOiCiOiCiCiCiCiOiCiOiCiCiOiCkCLOiOiCiCiO COCOCOCOC^CMCOCOCOCOCOCMCMCMC^CNCMCOCOCOeOCOCMCMCMCMCOCOCCiCOCOCOCM +3 CD fl £> . CD 5 -* O »*-i o p 7 a) ^ Op £ | E . .CMCMCMCM<>lCMCMCMCMCM 0> ^ 03 03 0 •2 1—1 8 o a> Drawn steel rods _do. .do. .do. .do. .do. .do. .do. .do. ..do. .do. Twisted fence wire .do. _do. _do. _do. _do. _do. _do. _do. _do. Barbed wire _do. _do. _do. _do. _do. _do. _do. _do. _do. _do. _do. Drawn steel rods ..do. .do. Twisted fence wire 0.08 .08 .08 .08 .08 .08 .19 .19 .19 .19 .19 .06 .06 .06 .06 .06 .06 .13 .13 .13 .13 .06 .06 .06 .06 .06 .06 .06 .06 .13 .13 .13 .13 .08 .19 .19 .06 Load at first crack. In Pounds. Maximum load. In Pounds. Equivalent load on 4-foot cantilever at first crack. In Pounds. Equivalent maximum load on 4-foot cantilever. In Pounds. 800 1120 218 306 820 1145 224 313 640 1080 175 295 795 1040 217 284 940 1170 257 319 740 1075 202 293 1140 1280 311 349 1170 1885 319 515 1020 1950 278 532 760 1945 207 531 820 1925 224 526 825 935 225 255 755 905 206 247 800 940 218 257 815 935 222 255 770 980 210 268 780 975 213 266 1550 1920 423 524 1275 1670 348 456 1200 1830 328 500 1500 1955 410 534 980 980 268 268 820 820 224 224 590 740 161 202 745 745 203 203 590 590 161 161 550 640 150 175 560 635 153 173 480 530 131 145 680 1040 186 284 840 1010 229 276 1280 1515 349 414 800 1375 218 375 Tested by impact .do. .do. .do. do .06 do Form of reinforcement. 1 } = }c U \l u . I \ [ 376 CEMENTS AND CONCRETES advantage over the barbed wire as a reinforcing material, particularly when two wires are used in each corner of the post. As stated before, it is impracticable to make a rein¬ forced concrete fence post as strong as a wooden post of the same size, and this is more especially true if the post First method of testing posts by impact. NO. 17. has to withstand the force of a sudden blow or impact. In order to study the behavior of these posts under im¬ pact, a number of them were braced, as illustrated in No. 17, and subjected to the blow of a 50-pound bag of gravel, suspended from above by a 9-foot rope. The first blow was delivered by deflecting the bag so as to give it a vertical drop of 1 foot, and for each successive HOW TO USE THEM 377 blow the drop was increased 1 foot. None of the posts showed any signs of failure under the first blow. Posts Nos. 14 and 20 cracked under the second blow, and failed under the third. Post No. 6 cracked under the second blow, which cracked open under the third blow, causing a momentary deflection of 5 inches. Posts Nos. 7 and 8 each developed a crack under the second blow, but showed no further signs of weakness after the fifth blow, Second method of testing posts by impact. NO. 18. other than a slight opening of the initial crack. In each case the only crack developed was at point A. Posts 6, 7, and 8, which cracked but did not fail under the im¬ pact test, were further tested, as indicated in No. 18, by raising the small end and allowing them to drop from successive heights at 1, 2, 3 and 4 feet. Under this test a number of cracks developed, but in no case did the re¬ inforcement fail. Although it might appear from these results that posts as here described have hardly enough strength to recom¬ mend them for general nse, it should be remembered that in many cases fence posts are not subjected to impact, 378 CEMENTS AND CONCRETES and it may prove more economical to replace from time to time those which fail in this way than to use wooden posts, which, being subject to decay, must all be replaced sooner or later. Diagram showing the effect of clay on cement mortars. NO. 19. Retempering .—Table III. illustrates the effect of re- tempering Portland cement mortar. The mortars used consisted of Portland cement and crushed quartzite be¬ tween 1 and 2 millimeters in size, mixed in different pro- HOW TO USE THEM 379 portions. In each case, after the initial or final set had taken place, sufficient water w r as added in retempering to TABLE III.— Effect of Retempering on Cement Mortars. Tensile Strength, in Pounds Per Square Inch. Treatment of Mortar. Neat Cement. a 1 Part Cement, 1 Part Sand, b 1 Part Cement, 2 Parts Sand, c 1 Part Cement, 3 Parts Sand, d Mortar made up into briquettes immediately after mixing. r . 651 650 673 634 679 624 701 624 581 610 527 493 529 480 492 417 385 421 403 409 Average . 657 628 504 407 Mortar allowed to take initial set, then broken up and made into briquettes. L 671 593 644 633 724 692 670 654 676 700 589 554 559 534 532 326 349 330 358 267 Average . 653 678 554 326 Mortar allowed to take final set, then broken up and made into briquettes. 455 522 525 558 642 527 569 587 566 568 492 491 497 486 531 364 380 361 315 345 Average . 540 563 499 353 a Initial set, 1 hour 42 minutes; final set, 7 hours 15 minutes. b Initial set, 1 hour 30 minutes - final set, 7 hours 15 minutes, c Initial set, 2 hours; final set, 7 hours, d Initial set, 2 hours 20 minutes; final set, 7 hours. restore normal consistency. The briquettes were tested at the age of four months. 380 CEMENTS AND CONCRETES Some Practical Notes .—Spencer B. Newbury, who is an authority on the subject, says “that the making of good cement concrete is a comparatively simple matter, and yet, like most simple operations in engineering, there is a right way and a wrong way of doing it. Probably nine-tenths of the concrete work done falls far short of the strength it might develop, owing to the incorrect pro¬ portions, use of too much water, and imperfect mixing. All authorities are agreed upon the importance of thor¬ ough mixing and the use of the minimum quantity of water in all classes of concrete work. The matter of cor¬ rect proportions of cement, sand, broken stones, etc., is one which requires some thought and calculation, and by proportioning these ingredients correctly an immense saving in cost and increase in strength can easily be se¬ cured. The chief object in compounding concrete is to pro¬ duce a compact mass, as free as possible from pores or open spaces; in short, to imitate solid rock as closely as possible. Cement is the “essence of rock” in portable form, and by its judicious use granular or fragmentary materials may be bound together into solid blocks of any desired size and shape, which in strength and wearing qualities are at least equal to the best stone that comes from the quarries. Cement is, however, very costly in comparison with the other ingredients of concrete, and must not be used wastefully. A little cement, judi¬ ciously used, is better than a large quantity thrown in recklessly, as a little study of the principles involved will plainly show. To produce a compact mass from fragmentary ma¬ terials, the voids must be filled. Imagine a box holding 1 cubic foot. If this were filled with spheres of uniform HOW TO USE THEM 381 size, the voids or open spaces would be one-third the total volume, or 33 1-3 per cent., with spheres of various sizes, as, for example, from large marble down to fine shot, the voids would be much less, and it would theoretically be possible, by the use of spheres of graded sizes, from the largest down to dust of infinite fineness, to fill the box completely, so that there would be no voids whatever. In practice it is well known that the use of materials of varying fineness gives the best concrete, since the voids are much less than in materials composed of pieces of uniform size. Hence the common practice of making concrete with cement, sand and broken stone, instead of with cement and sand, or cement and stone only. The sand fills the voids, and if the proportions are correct, a practically solid mass results. As an example of this, the writer found the briquettes of cement with three parts of sand and four parts gravel showed higher ten¬ sile strength at 28 days than those made with three parts sand only. The following table gives the relative weights of a given volume of different materials, and also the per¬ centage of voids, as determined by the writer. The ma¬ terials were shaken down in a liter measure by giving one hundred taps on the table, and weighed. In the case of the broken stone a larger measure Avas used. The voids were calculated from the specific gravity. Comparison of the three different grades of Sandusky Bay sand shows how greatly the percentage of voids varies with the proportion of fine and coarse grains pres¬ ent. The first is the natural sand, not screened, as pumped up by the sand sucker from the bottom of the bay, and contains a large amount of fine gravel. The second is the same, passed through a 20-mesh screen to 382 CEMENTS AND CONCRETES remove the coarse particles. It will be seen that this operation increases the proportion of voids from 32 to 38 per cent. The third is the same sand passing a 20- mesh and retained on a 30-mesh screen, thus brought to the fineness of the “standard sand” used in cement test¬ ing. This shows 40.7 per cent, of voids, owing to the uni¬ form size of the grains. The same relation is seen in the WEIGHT OF UNIT MEASURE AND PERCENTAGE OF VOIDS IN VARIOUS MATERIALS. - Weight of 1 Liter. Per Cent of Voids. Portland cement. 1720 g Louisville cement. Sandusky Bay sand, not screened. 1780 g 32.3 Sandusky Bay sand, through 20-mesh screen . 1630 g 38.5 Sandusky Bay sand, 20-30 mesh (standard sand). 1570 g 40.7 Gravel, to % inch. 1510 g 42.4 Gravel, x /i to inch. 1680 g 35.9 Marblehead broken stone (chiefly about egg size) . 1380 g 47.0 two grades of gravel given in the table, that containing finer grains showing much the lower percentage of voids. These figures illustrate the imprudence of screening any of the materials used in making concrete. The pres¬ ence of clay in sand is, however, objectionable, not be¬ cause of its fine state of subdivision, but because the clay coats the sand particles and prevents the adhesion of the cement. Such sand might be improved by wash¬ ing, but probably not by screening. It has been found HOW TO USE THEM 383 that cement which ha§ been ground to dust with an equal amount of sand goes much further when used for con¬ crete than the same quantity of cement when used in the ordinary way. This is doubtless owing to the fact that the sand dust aids in filling the voids. It is also well known that slaked lime, when added to cement mor¬ tar, greatly increases the strength of mixtures poor in cement. From the figures given in the above table the compo¬ sition of a theoretically perfect concrete may readily be calculated. The existence of voids in the cement may be disregarded, since in the process of hardening the cement sends out crystals in all directions, completely encrusting the sand particles and practically filling all the voids which the cement itself contains. Examination of a well-hardened briquette of cement with 3 parts sand, after breaking, with the aid of a lens, will show this clearly Suppose, for example, we wish to make the best pos¬ sible concrete from Portland cement with the sand and gravel given in the above table. We should, of course, choose the unscreened sand and gravel as containing the least proportion of voids. One hundred measures of gravel would require 35.9 measures of sand. As the sand contains 32.3 per cent, of voids, we require 32.3 per cent, of 35.9, or 11.6 measures of cement. The pro¬ portions would, therefore, be: Cement, 11; sand, 3, and gravel, 9. It is customary, however, to increase the pro¬ portion of mortar (cement and sand) by about 15 or 20 per cent., in order that the coarser materials may be completely coated with the finer mixture. Making this addition, we find the concrete proportions to be: Cement, 1; sand, 2.8; gravel, 7. Allowance must also be made in 384 CEMENTS AND CONCRETES practice for imperfect mixing, since the materials can never be distributed in a perfectly uniform manner. Practically, with these materials, a concrete of cement 1, sand 2 y 2 , and gravel 6, would probably give the best result, and little or no improvement would result from increasing the proportion of cement. A similar calculation shows that the correct propor¬ tions for a concrete made of the sand and broken stone given in the table would be 1 to 3 to 6y 2 . Increasing the amount of cement and sand by 20 per cent., we have 1 to 3 to 51 / 2 . Probably 1 to 2 y 2 to 5 would be found tc give the best results in practice. The determination of the voids in the sand, gravel and broken stone used is of the greatest value in adjusting the proportions of concrete. The simplest method of determining this in the case of gravel and broken stone is to have a metal box made of 1 cubic foot capacity; this is filled with the material to be tested, well shaken down and struck off level. The box and contents are then weighed. Water is now poured in until it rises even with the surface, and the total weight again taken. The difference in the weights is the weight of the water filling the voids of the ma¬ terial. Now 1 cubic foot of water weighs 64 4-10 lbs., and from the weight of the water found the percentage of voids can be simply calculated. For example, in one experiment the box and broken stone weighed 88 lbs. After filling the spaces in the stone with water the weight was 117!/2 lbs., a difference of 29y 2 lbs. The percentage of voids is, therefore, 2914x100 divided by 62.4 equals 47 per cent. In the case of sand this method will not answer, as it is difficult to completely fill the voids of the sand by HOW TO USE THEM 385 adding the water. The voids can, however, be readily calculated from the weight of a cubic foot and the spe¬ cific gravity. The specific gravity of quartz sand is about 2.65. A cubic foot of sand, free from voids, would therefore weigh 2.65x62.4 equaling 165.4 lbs. The weight of a cubic foot of sand, well shaken down, was, however, found to be only 112 lbs., a difference of 53.4 lbs. The proportion of voids was, therefore, 53.4x100 divided by 165.4 equals 32.3 per cent. The percentage in voids in clean natural sand does not vary greatly, and may be taken as 33 to 35 per cent, for coarse and 35 to 38 per cent, for fine sand. We have already seen that with the materials above described, concrete composed of Cement 1, sand 2y 2 , gravel 6, or Cement 1, sand 2 y 2 , broken stone 5 by measure, will be practically compact and non-porous, and that there is no object in increasing the proportion of cement. Such concrete, if made from Portland cement, will, however, be rather expensive, requiring about one barrel of cement (equals 3 y 2 cubic feet) for every cubic yard. This is unnecessarily good for ordinary work, and will only be required for foundations of engines and other heavy machinery, in which the best possible result must be secured regardless of cost. In cheaper concretes the relative proportions of sand and broken stone should be the same, as determined by the voids in the coarser materials, while the proportion of cement may be varied according to the required conditions of quality and cost. Most excellent concrete may be made by using: Portland cement 1, sand 7, stone or gravel 14. Here are specimens of these two concretes, taken from trial blocks laid Oct. 1, 1894, to determine the best pro- 386 CEMENTS AND CONCRETES portion for the foundation of brick pavement. The richer of the two, 1-5-10, is certainly good enough for any purpose, even for engine foundations. A cubic yard of such concrete requires about y 2 barrel of cement; the total cost of the cement, sand and stone is about two dollars per cubic yard. This is no niore expensive than concrete made from Louisville cement with 2 of sand and 4 of broken stone, and is immensely superior to the latter in strength. The following table shows the results obtained in Germany by R. Dykerhoff in determining the crushing strength of various concretes. The blocks used were 2 y 2 inches square, and were tested after one day in air and 27 days in water. Proportions by Measure. Strength under Compression. Pounds per Square Inch. Portland Cement. Sand. Gravel. 1 2 2125 1 2 3 2747 1 2 5 2387 1 .. 5 978 1 3 1383 1 3 5 1632 1 3 6X 1515 1 4 1053 1 4 5 1273 1 4 8% 1204 These figures prove the statement already made, that mixtures of cement and sand are strengthened, rather than weakened, by the addition of a suitable quantity of gravel. It will be noticed that the mixture—cement 1, HOW TO USE THEM 387 sand 2, gravel 5—is actually stronger than cement 1, sand 2, without gravel. The same is shown in the mix¬ tures 1 to 3 and 1 to 4. In estimating the amount of material required to pro¬ duce a given volume of concrete, it may be stated that when very strongly rammed into place the volume of concrete obtained from correct proportions of the ma¬ terials will be about 10 per cent, more the volume 1 cubic foot cement, 2 y 2 cubic feet sand, and 5 cubic feet stone, and will therefore yield about 5y 2 cubic feet concrete. Another Concrete Stairway and Steps .—A good stair¬ case is one of the essential features in a building. The safety and convenience of persons using a staircase are not only affected by the due proportions and arrange¬ ments of the steps, but by the strength and fire-resisting properties of the materials employed, and the manner of construction. The wells are in many cases too small, out of proportion to the structure, which necessitates dangerous winders, tiring high risers, narrow treads, or insufficient headway. Some architects when designing a staircase pay little attention to the practicability of con¬ struction. What may seem easy in theory or on paper is often found impracticable or unnecessarily difficult when reduced to actual practice. The errors of omission and commission are left for the workmen to contend with and overcome as best they may at the employer’s expense. Happily such cases are few, the majority of architects supplying figured drawings, which are not only a help and guide to the workmen, but also ensure a practical staircase in due proportion and without un¬ necessary expense. Staircases should be spacious, light, and easy of ascent. It is generally admitted that a 12 inch tread and a 6 inch rise is the most convenient, and 388 CEMENTS AND CONCRETES that no tread should be less than 8 inches or more than 16 inches, and no rise less than 4y 2 inches and more than 7 inches. According to Blondel, the rise should be re¬ duced y 2 inch for every inch added to the tread, or the tread reduced by 1 inch to every y 2 inch added to the riser, taking a 12 inch tread and a 6 inch rise as the standard. Treads may be increased by means of a nos¬ ing, which usually projects from 1 inch to 1 y 2 inches. Nosing not only gives more available space for the tread, but also affords some advantage to persons going down stairs, as the heel cannot strike against the rising. In setting out a flight of stairs, the tread of the steps are measured from riser to riser. Where practicable, the number of steps from landing to landing should be odd, because when a person begins to ascend with the right foot first (as most people do) he should end with the same foot. Rectangular steps are called fliers. Wind¬ ers, being narrowed at one end, are always more in¬ convenient and dangerous than straight steps, and should not be used for public buildings or other places where there is a crowded traffic. Winders are also more expensive to construct. They are, however, un¬ avoidable in circular staircases, also in some instances in angles, where a quarter or half space landing would not give the desired rise. Winders should be so made that the tread 6 inches from the end of the narrow point should be wide enough to step upon without dan¬ ger of slipping. No stairs should be less than three feet from the wall to the hand-rail. A width of 3 feet 6 inches will allow two persons to walk arm in arm up or down stairs. A width of 4 feet6inches is generally used; this gives plenty of space for two persons to pass each other. No hard and fast rules can be laid down for the HOW TO USE THEM 389 size of treads and risers, as they are regulated more or less by the size of the well and the height from floor to floor. Too few steps in a flight are as bad as too many. There should not be less than three. Long straight flights of steps are tiring and dangerous. The straight line of length should be broken by landings, so that there may not be more than eleven continuous steps. Landings give ease in ascending and safety when descending. No landing should be less in length than the width of the staircase. The staircases in the pre-Elizabethan style were usually plain, dark and in long narrow flights; but with the Elizabethan archi¬ tecture came in a more commodious, light and decora¬ tive style. Wood stairs are often enriched with plaster work, the soffits being panelled with plaster, and the strings adorned with composition or plaster enrich¬ ments. Stone stairs are also frequently enriched with plaster mouldings in the angles of the soffits and walls. External steps and landings are usually made with a fall of V 4 inch to the foot to allow rain to fall off. Cast Concrete Stairs .—Concrete is now fast super¬ seding stone, wood and iron for staircase construction, where strength, durability and economy and fire-resist¬ ing properties are required. Cast concrete stairs were first introduced nearly sixty years ago. The stairs were cast in single steps, or in treads or risers, and fixed in the same way as natural stone. Square and spandrel steps, risers and treads are cast in wood moulds; circular steps and curtails in plaster moulds. Spandrel steps should have the wall or “tail” end formed square, and about 4% inches deep, to give a better bed and bond in the wall. A good mixture is 3 parts of granite or slag chippings and 1 of Portland 390 CEMENTS AND CONCRETES cement, ganged stiff, and well rammed into the moulds. When set they are removed from the moulds, air dried, and placed in water or a silicate bath, and treaded in a similar way to that described for slabs. For long steps pieces of T iron, or iron pipes, are sometimes in¬ serted in the centre of the concrete while being cast. The iron is not actually required to strengthen con¬ crete properly made, but is used to give a temporary strength to the cast while it is green, so as to allow more freedom and security in handling the cast when it is being taken from the mould and moved about till permanently fixed. Landings are cast in a similar way, but unless very small, they are best done in situ. I have made landings up to 40 feet superficial, but owing to the cost of transit, hoisting and fixing they were not profitable. Tests of Steps .—The following examples show the strength of concrete steps: In Germany, when con¬ structing a concrete stair, with square steps 3 feet 4 inches long, and 6 -inch tread, and 6 i/ 2 -inch rise, and one end set 8 inches into the walls, four steps were sub¬ mitted for trial, and 5,940 lbs. weight of iron were gradually piled on them. The steps showed no signs of fracture, but no more weight could be put on be¬ cause the masonry began to yield. The load was left on three days, and the steps remained unaffected. Al¬ though numerous tests have been made of concrete floors and blocks, few have been made for concrete steps. The following may be given as a reliable one: The steps were about 6 feet long, 11-inch tread and 6 -inch rise. Every step was tested in the presence of the foreman concreter and author. The steps were supported at both ends, and weighed with a distribu- J HOW TO USE THEM 391 tive load. The majority, which were matured by age, passed the specification standard. Concrete Stairs Formed “in Situ .”—Concrete stairs are an outcome of stairs built with cast concrete steps. Stairs formed in situ were introduced in 1867. The idea was suggested by the use of reverse moulds for fibrous plaster work, and in the formation of concrete dormer windows made in situ on some mansions. The step landings and the wall bond, being a monolith structure, were to a certain degree self-supporting. They tend to strengthen instead of to weaken the walls. Architects generally supply drawings of the intended staircase, but as there is often a differ¬ ence in the size of the details of the actual work and the drawings, it is necessary that the workman should have a practical knowledge of setting out the “height” and “go” for the pitch board, to suit the landings and the well of the staircase, and ensure the necessary head- room. Setting Out Stairs .—A correct method of setting out the framing for concrete stairs is of primary import¬ ance. The height of a stair is the length of a per¬ pendicular line drawn from the upper of a floor to that of the one immediately above it. The “go” is the length of a horizontal line drawn along the centre line of the flight of steps or stair space. The exact height and widths should be taken on a rod, which should afterwards be used for setting out the work. Never work without this rod, as it is quicker and more accurate than measuring with a 2-foot rule. There are various ways of getting the dimensions of treads and rises. The following is a simple one and answers for most purposes. The height and go are taken and suitably 392 CEMENTS AND CONCRETES divided. For example, if the height from floor line to floor line is 9 feet 3 inches, and it is proposed to make each rise 6 inches high, reduce the weight to inches, which would be 111; divide by the proposed height of each step—6 inches—the quotient will he 18, giving the same quotient 6 and 3-18. If there are intermediate landings, or half spaces, their dimensions must he allowed for. The size of the tread is obtained by dividing the “go” by the number of steps. The quotient will be the width of the tread. Great care should be taken in setting out the rods and pitch boards. It is better to measure thrice than to cut twice. When the string line is marked on the wall, a chase about 414 inches deep is cut into the wall. It is not necessary to cut the chase straight at the soffit line, as it is apt to cut into a half, or rather a whole brick, and leave the ends loose. The irregular line of chase below the soffit line can be made solid during the pro¬ cess of filling in the steps. The chase should be cut as the work proceeds. Not more than one flight at a time should be cut, to avoid weakening the wall. In some instances a brick course in sand is left by the bricklayers. The bricks are then taken out as the work proceeds. Nosings and Risers .—Nosing mouldings should be strong and bold. A simple but well-defined moulding not only gives greater strength, but is more in keep¬ ing with its purpose than one with numerous or small members. Nosing and riser moulds are best formed in two parts, the nosing moulds being one part and the riser board the other. To cut them out of the solid would not only be expensive, but also cumbrous to fix. They can be run at most saw and moulding mills. HOW TO USE THEM 393 They should he run in lengths and then cut and mitred on the job. Illustration No. 20 shows various forms of nosing. Fig. 1 is a simple nosing for common work. Fig. 2 may be used for school stairs, etc. Figs. 3 and 4 are well adapted for a good class of work. It will be seen that the lower edges of the riser boards are splayed. This is to admit the shoe of the running- mould; also a trowel to work close up to face of the Fig. i. Fig. 2. Fig. 3. Fig. 4. Sections op Nosino Moulds with Riser Boards. NO. 20. concrete riser when running and trowelling off the treads. The dotted lines indicate the line of tread. Nosing moulds are cut in the centre of the section, and afterwards the two parts are held in position with screws while the steps are being filled in. This allows the upper part to be unscrewed and taken off when the stuff is nearly set, thus allowing more freedom to trowel the surface of the tread; also to make a better joint while the stuff is green, and at the part that is cast and the part to be trowelled. The joint in the nosing mould leaves a thin seam which is easily cleaned off, whereas the joint of the tread and nosing is not only seen more, but is also more difficult to make good. 394 CEMENTS AND CONCRETES Illustration No. 21 shows the mould and joint - and screws for fixing same. Framing Staircases .—The wood framing for con¬ crete stairs differs from and is partly the reverse to that used for wood stairs. The nosings are formed the reverse of the moulding, and the whole framing is so constructed that it forms a mould to cast all the steps and landings, from floor, in monolithic form, or one piece. When the positions of half spaces or other Jointed Nosincj Mould with''Riser Board. NO. 21. landings are set out on the walls, strong planks are fixed on edges so as to give fixing joints for the car¬ riage and outer strings. The strings are then fixed to act as guides for fixing the centring, risers and nos¬ ing moulds. Where practicable, the outer string should be so arranged in the fixing that it can be taken off after the concrete is firm without disturbing the cen¬ tring. This allows the returned ends of the steps to be cleared off while the work is green. The carriage boards are fixed from landing to landing. Illustra¬ tion No. 22 shows the forms and positions of the vari- 4^\C/ta^ euf tyffo (| Framing for Concretb Stairs Constructed in situ. NO. 22. 396 CEMENTS AND CONCRETES ous parts, with their names. Bullnoses or curtails and circular parts of nosings are formed in plaster moulds, which are run with several reverse running' moulds. Staircases between walls are more simple than open staircases; therefore they are more easy to frame up. The string: boards are cut to the reverse of that used for wood stairs. A string- is cut for each wall. The riser boards are then fixed to the wall strings. The centring for the soffits is fixed independently, the boards being laid on fillets which are nailed on each wall. For short flights of steps or common stairs, such as for cellars, etc., string boards may be dispensed with. The positions and sizes of the risers, treads, soffits and landings are first set out and marked on the walls. Riser fillets are then nailed on the walls, taking care to keep each fillet in a line with the riser mark, and to allow for the thickness of the riser boards which are subsequently nailed on the inner sides of the fillets. Riser boards for winders are generally hung on long fillets and then nailed on the walls. Long fillets ex¬ tending upwards enable the work to be easier and more strongly fixed, as they cover more brick joints than if cut to the exact height of the riser. Centring for Landings and Soffits .—Centring for landings and the soffits of stairs should be made strong and true. The timber should be well seasoned, to pre¬ vent warping or shrinkage. The outer angles of land¬ ings should be supported by strong wood props, not only to carry another prop for the landing above. All centrings should be made perfectly rigid, to stand the weight of the concrete and the ramming. Great care should be taken that the timber framing is securely supported, as any deflection will not only throw the HOW TO USE THEM 397 work out of level, but will also tend to crack the con¬ crete. The principal props should be cut about % inch shorter than the exact height. They are placed on a solid bed, the ^-incli space at top being made up with two wedges, the thin ends being inserted in opposite directions and gently driven home from each side until the exact height is obtained. If it is dif¬ ficult to get the top of the prop, the wedges can be inserted at the bottom. The use of the wedges will be seen when the centring is struck. If there are winders in the stairs, the centring for the soffit will be more or less circle on circle. This form of centring is done by lathing, with 1-inch boards, cut to a taper, the surface being made fair with a gauged lime and hair. Rough 1%-inch boards are used for the centring. This should be close-jointed. Open joints or sappy timber act as a sieve, and allow liquid cement to drip through, thus robbing the concrete of its strength. Waterproof Centring .«—The following is a method that has been used with marked success for the sof¬ fits of stairs, landings and the ceilings of floors. The initial cost of preparing is small, and is repaid with interest by the decreased cost of setting and the in¬ creased strength and solidity. For ordinary work, such as warehouses, etc., it is very suitable, as a fin¬ ished surface is formed, and no setting required. It seems strange that, when casting concrete work out of a wood or a plaster mould, the mould is seasoned, and every precaution taken, not only to stop suction, but also to prevent the escape of liquid cement; but when casting a large surface in situ (where every precau¬ tion should be taken to obtain the maximum of strength), any kind of centring (which is a mould) 398 CEMENTS AND CONCRETES is thought good enough, if only sufficiently strong to carry the concrete till set. I am aware that many workers in concrete think that an open or porous centring is a benefit instead of a defect, simply be¬ cause it affords an escape for excess of water. But why have excess of water at all? There is no gain in time or strength, but a direct loss in both points. The excess water descends through the concrete by force of direct gravitation, and always carries a cer¬ tain amount of liquid cement with it to the centring, leaving the aggregate more or less bare, and the body of the concrete weak. A part of the liquid cement also oozes through the joints and crevices, which leaves the skin of the concrete bare and broken. There is no reason or excuse for excess water, and it is simply the result of ignorant or careless gauging, which is not only a waste of time, water and cement, but a loss in the ultimate strength, and the cause of cracks. Porous centring is also a dirty process. The overhead drip, drip, is neither good for the workmen nor the material underneath. The process of forming the rough centring boards watertight is simple and expeditious, being done by lajdng the rough board surface with a thin coat of gauged plaster; and when the centring has been struck the plaster will come with the boards, leaving the con¬ crete with a fair face. The ramming forces a certain amount of water to the lower surface or centring, and this is so close and tine that it takes an exact impress of it; consequently the truer and smoother the centring the truer and smoother the concrete surface. The film of water indurates the skin of the concrete and prevents surface or water cracks. It will be noticed when tilling HOW TO USE THEM 399 in dry or porous plaster moulds that the concrete cast produced has a surface either friable when newly cast, or when dry the surface is full of small water lines, like a map, or a broken spider’s web. This is owing to the suction caused by the porous nature of the mould and the water escaping through the weak or open parts leaving corresponding lines on the concrete surface. These defects are obviated by using waterproof cen¬ tring. Where fineness of finish is not required, such as ware¬ house floors, the surface can be made sufficiently fair and smooth when filling in the concrete without sub¬ sequent setting. The plaster is laid on the centring, and made fair and smooth, and then the surface is saturated with water to correct the suction; or the surface, if dry, may be brushed over with a thin soap solution to prevent adhesion. On this surface a coat of neat cement about inch is laid, and on this the concrete is placed. The two unite in one body, and when set, and the centring struck, the plaster sheet comes with the boards, leaving a smooth surface. This surface can be made in color by lime washing, which will also give more light, or a finished white surface can be obtained by substituting parian or other white cement for the neat Portland cement. The concrete must not be laid until the white cement is firm, not set, otherwise the concrete will force its way in thin or soft parts and disfigure the surface. I have success¬ fully used this method for obtaining a finished sur-. face when encasing iron girders with concrete for fire¬ proof purposes. Staircase Materials .—With regard to the materials for a concrete staircase, no one who intends to con- 400 CEMENTS AND CONCRETES struct them substantially, fireproof and economically, can afford to use common substances, when by judi¬ cious selection and for a trifling additional first cost a combination of materials can be obtained, which, if not (strictly speaking) fireproof, is at least the most incombustible constructive compound known. This is a quality of the most vital importance in modern house construction. Portland cement and slag cement are the best known matrices. The finer Portland cement is ground, the greater its heat-resisting powers.. Slag cement is lighter than Portland cement, and its fire- resisting properties exceed those of both gypsum and Portland cement. But as its manufacture is as yet somewhat limited, and its strength not uniform, ex¬ ceptional care must be exercised in testing its general qualities before using it for staircases. Broken slag, firebricks, clinkers and pottery ware are the best ag¬ gregates, being practically fireproof. All should be clean, and in various graduating sizes, from that of a pin’s head to that of a walnut, for roughing out with. The topping should be the same as that described for Eureka paving. Filling in Stairs .—Before gauging the materials, sweep out all dust in the interior of the framing and the wall chase and then wet the latter, and oil the woodwork. If the wood of the nosing moulds and risers is sappy or open grained, the long lengths, be¬ fore being cut and fixed, should be made smooth and indurated by coating with a solution of hot paraffin wax. The smoother and less absorbent the surface of the wood, the more readily and cleaner will the mould leave the cast work. Paraffin also renders the wood damp-proof, thus preventing swelling or warping. For HOW TO USE THEM 401 ordinary purposes one or two coats of paraffin oil will be found sufficient. This should be done two or three hours before the steps are filled in, so as to allow the oil to partly dry in and stop the pores of the wood. If the wood absorbs all the oil, and has a dry sur¬ face, brush the surface again w*ith paraffin, using a semi-dry brush. This should be done as the work pro¬ ceeds. If the surface is over wet, the oil mixes with the cement, thus causing a more or less rough sur¬ face. Soap solution may be safely used for rough concrete, or where a rough surface is left to be sub¬ sequently set. In the latter case the surface must be well wetted with water and scrubbed before the final coat is applied. Soap solution may also be used for rough framing, such as soffit boards, but soap should not be used for fine concrete or a finished surface, as it leaves a film of grease which has a tendency to prevent the cement adhering when clearing up or mak¬ ing good the finished surface. As the work of filling proceeds, the surface should be brushed over with a slip, that is, neat cement, to fill up all angles, and obtain a surface free from “bulbs” and ragged ar¬ rises. The coarse concrete for roughing out the stairs is composed of 1 part of Portland cement and 3 parts of coarse fireproof aggregate. These materials must be gauged stiff and laid in small portions of about a pail¬ ful at a time, taking care to thoroughly consolidate by ramming and beating with a wooden mallet, using a wooden punner or punch to get into the angles and deep parts. When the first layer, which may be about 3 inches thick, is rammed, another layer is deposited and rammed, and so on until the rough stuff is within 402 CEMENTS AND CONCRETES i/ 2 inch of the line of tread. It must not be omitted to brush the strings, treads and nosing moulds with slip as the work proceeds. This is most effectually done by the aid of a tool-brush. Care must be exercised when ramming stairs with mallets or punches that the mallet or other implement used is not too large or too heavy, for it would most likely cause the framing to bulge out, and the form of the work would be irre¬ trievably spoilt. During the operation of ramming some of the water and a part of the constituent of the cement is forced upwards, and leaves a thin, smooth, clayey film on the surface, which prevents the adhesion of the next layer. For this reason the successive lay¬ ers should be deposited before the previous one is set, and the topping should be laid while the coarse con¬ crete is yet green. Too much stress cannot be laid upon the importance of topping the rough coat while it is green. This is one of the secrets of success of solid and strong work, so no more rough stuff should be laid than can be topped before the rough is set. The fine stuff for the topping is the same as for Eureka paving, viz., 1 part of cement to 2 parts of fine aggregate, gauged firm and plastic. The tread is made level and fair by means of a running mould so formed that it bears on the nosing moulds above and below the tread. The mould has a metal plate or “shoe” fixed so as to run and form the tread. The shoe projects so that it will work under the riser board close up to the concrete riser. Illustration No. 23 shows a sec¬ tion of steps with the mould in position; also a sec¬ tion of the nosing mould and soffit boards and car¬ riage. The end of the slipper next to the wall is cut short to allow the mould to run close up to the wall. A HOW TO USE THEM 403 section of a T iron is shown as sometimes used as an in¬ ternal support. Iron is used for long steps, or where stairs are intended for heavy traffic. Iron helps to sup- —Sections of Framing ok Soffit of Stair, Riser And Noser Mould, with Concrete and Tread Run¬ ning Mould in Position. NO. 28. port the concrete until set; it is placed in alternate steps, or in every third or fourth step, according to the length of step. Ordinary sized steps recpiire no iron, 404 CEMENTS AND CONCRETES unless as a support for the concrete while green, and during the process of making. Finishing Stairs .—When the treads are firm after being run, the upper part of the nosing moulds are removed, the surface and joists trowelled off. The ad¬ vantages of having the nosing mould in two parts will thus be seen, as it allows the joint at this most notice¬ able part to be neatly cleaned off while the work is green. The lower part of the mould will support the concrete nosing during the finishing of the tread and until the concrete is set. If the work is done with a nosing mould in one piece, which necessitates its being left on until the concrete is set, the joint has then to be filed down and stopped, and however well done, has a patchy appearance. When the treads are finished, and the work set, but not dry, the riser and string boards are taken off, the joints made good, and the returned end of the steps cleaned off. If the stuff has been properly gauged and rammed, there should be little or no making good required, but it is important that if necessary it should be done while the work is green. A thin layer of neat cement will not adhere on a dense and dry body of concrete. The only way to obtain perfect cohesion is to cut the damaged surface out to a depth of not less than 14 inch, then thoroughly wet it, brush the surface with liquid cement, and fill it in with gauged cement. No traffic should be allowed on the treads during the process of setting and harden¬ ing. The work is further protected and hardened by covering with sacks kept wet for several days by fre¬ quent watering. Where there are several flights of stairs to construct, there should not be less than three sets of strings and riser boards, which will enable the HOW TO USE THEM 405 carpenter to fix one set while the plasterers are filling in and cleaning off the others. Non-Slippery Steps .—Incessant traffic tends to make the treads of steps more or less slippery. In order to obviate this, the surface is indented with a concrete roller, similar to that used for some kinds of paving. Another way is to form three or four Y-shaped grooves from 1 inch to 2 inches apart on the treads while the concrete is moist. Another way is to insert leaden cubes about 1 inch square from 2 to 3 inches apart in the surface of the treads. Well-seasoned, hard wooden blocks, about the same size as the lead and fixed in a similar way, keeping the end grain vertical, are also used for this purpose. India rubber and cork cubes may also be used. Striking Centrings .—This should not be attempted until all the other work, with the exception of finishing the soffits, is done. It will be understood that the framing can be arranged so that the string and riser boards can be taken off without disturbing the soffit centring, which is kept up as long as possible. The time for striking centring greatly depends upon the class of cement used, the manner of gauging and lay¬ ing the concrete, and the temperature; but generally speaking, centring should not be struek for at least ten days. A stair between the walls can be struck much sooner than one having only one bearing by which its own weight is carried. I have seen a stair, with steps projecting 3 feet 6 inches from the wall, cleared of all supports in five days from the time of filling in; but this was with good cement, gauged 1 part to 2 of aggregate, and in warm weather, and the stair was strengthened with T iron. 406 CEMENTS AND CONCRETES The centring and framing for a flight of stairs should, where practicable, be independent of other stairs above or below, so that they can be struck in due rotation. The wedges of the main props should be gradually withdrawn. This tends to avoid the sudden jar which otherwise often happens when the centring is too sud¬ denly struck. The sudden removal of centring and the inflexible nature of concrete are the cause of body cracks. The damage caused by the sudden jar may not be seen at the time, but it will be eventually devel¬ oped by the force of expansion, which always finds out the weak spots. Concrete and Iron .—Iron pipes, bars and T pieces are sometimes used with concrete stairs where the steps are long, or where landings have little support from walls. They help to carry the dead weight until the mass is thoroughly set, and also prevent sudden de¬ flection if the centring is struck too soon. When iron pipes are used for steps they should go right into the wall chase. Iron T pieces are used for long landings. Care must be taken that, if the iron is used, no part should be left exposed. It must be embedded in the concrete to protect it from oxidization and the effects of fire. When iron girders, etc., are partly exposed, they should be painted. Iron bars or pipes are -occa¬ sionally used to strengthen the outer strings of spandrel stairs. The iron is laid in the moist concrete near and along the string, having the ends projecting into the walls or landings. Angle irons are often used for unsupported concrete angles. Iron pipes, bars or joists are used as integral supports for landings and floors having unsupported ends. The tensile strength of bar iron is materially in- HOW TO USE THEM 407 creased by twisting. A bar % inch square with three twists per foot will gain about 50 per cent, in tensile strength when embedded in concrete, and give a corre¬ sponding strength to the concrete. A combination of iron and concrete is of special service where space is limited. For instance, if a beam or landing requires a certain thickness to carry a given weight, and it is inconvenient or difficult to obtain that thickness, the requisite degree of strength with a reduced thickness may be obtained by the combination of both materials. This gives the combined iron and concrete a useful ad¬ vantage over stone. It is important to secure the full strength of the iron, and that none be lost or neutral¬ ized. In order to obtain the full strength the iron should be judiciously placed. Thus, a piece of iron surrounded by twenty times its sectional area of con¬ crete would increase the weight-sustaining power of the iron in the centre and would have its strength in¬ creased about twice. If the same quantity of iron was placed in several pieces, so as to throw as much tensile strain on the iron as possible, the strength would be increased nearly four times. In order that none of the strength be lost or neutralized, the iron should be placed near the lower surface; if fixed higher, they are nearer the axis of neutral stress, and are correspond¬ ingly less effective. The use of iron in concrete is in¬ valuable for many constructive purposes, but for gen¬ eral work, unless as a temporary aid and in a few ex¬ ceptional cases, it is unnecessary. For all other things being equal, the huge board of reserve strength in good concrete is alone sufficient to sustain as great if not a greater weight than that sustained by natural stone. No other artificial compound exceeds the strength of the 408 CEMENTS AND CONCRETES natural substance, as does artificial stone composed of Portland cement concrete. Setting Concrete Soffits .— 1 The soffits of stairs and landings, if neat cement has been used on a water¬ proof centring, as already described, only require a lit¬ tle stopping and coloring, but for work done on rough centring a setting coat has to be laid. This is usually done with neat Portland cement, though it is frequently gauged with lime putty to make it work more freely. The surface should be well roughened and wetted, to give a key and obtain perfect cohesion. It requires great care and time to make a good and true surface with Portland cement on a body of concrete, espe¬ cially if the concrete is dry, which is generally the case where there are several flights of steps in a stair¬ case, and the setting of the soffits and landings are left to the last part of the work. I have obtained equally good results by using Parian or other white cements for setting the soffits of staircases. When using white cements for this purpose it is better to brush the concrete surface with liquid cement before laying the gauged cement. The laying trowel should follow the brush, or at least before the liquid cement dries in. This not only secures better cohesion, but tends to prevent the setting coat peeling when trowel¬ ling it off. Soffits are sometimes set with gauged put¬ ty. This is like putting a beggar on horseback, and the work is never satisfactory. Fibrous Concrete .—As already mentioned, canvas and other fibrous materials may be advantageously used with Portland cement for several purposes. Can¬ vas forms a good ground for a setting coat on concrete surfaces. It gives a uniform and strong key, prevents HOW TO USE THEM 409 surface cracks, and the final coat from peeling. Coarse canvas cut to convenient sizes is used. It is laid on the centring, and held in position with tacks, or with the same kind of cement as intended for the final coat. The canvas is then brushed with liquid cement, and then the concrete is laid while the canvas is moist, so that the whole will form one compact body. When the centring is struck, the fibrous concrete surface is rough¬ ened with a sharp and fine drag, so as to raise the fibre of the canvas, thus giving a fine, regular and strong key. This surface requires less material for the final coat than the ordinary concrete surface. If tacks are used they must be extracted before the final coat is laid, to avoid discoloration. The rough concrete and the white surface coat may also be done in one opera¬ tion. The centring is made fair and smooth, and then oiled with chalk oil. The white cement is gauged stiff and laid on the centring. Coarse canvas is then laid on and well brushed with liquid cement. When this is firm (but not set) the surface is again brushed, and then the concrete is laid. The concrete is deposited *in^two or more layers. The first must not be too thick, taking care that it is well rammed or pressed on the moist canvas surface without disturbing the white ce¬ ment. After the centring is struck any defects on the surface are made good. The surface may be then left white, or painted, or polished as required. Polished Soffits. —Soffits, landings and strings of con¬ crete stairs that are finished in white cement may be polished. The material may be tinted, or left in its natural white or creamy color. Polished cement work is always bright, and has a lustre like marble. Be¬ ing durable and easily cleaned, it is mo.re sanitary and 410 CEMENTS AND CONCRETES cheaper than paint. The polishing is done the same way as described for 11 white work.” Concrete Staircases and Fibrous Plaster .—Fibrous plaster is well adapted for concrete surfaces when an enriched finish is desirable. I have introduced this material for decorating the soffits of steps and land¬ ings ; also the strings of concrete stairs. By this method the soffits may also be enriched, and strings can be panelled, or enriched with medallions or foliage, as re¬ quired. The soffits may also be enriched with modelled work done in situ, with some of the white cements, or with plaster and tow. The strings may be decorated with hand-wrought gesso. In order to obtain a fixing or keying substance that will receive nails or screws to sustain the fibrous plaster, a rough plan of the de¬ sign, or rather the fixing points, is set out on the in¬ side of the centring before the concrete is laid. On these plans wood plugs, fillets or concrete fixing blocks are laid, and held in position with nails, plaster or ce¬ ment until the concrete is laid and set. Care must be exercised when fixing the plugs or fillets that the centring will leave freely without disturbing the plugs, * etc. Dowel Holes .—Cutting dowel holes in concrete to receive iron or wood balusters is a slow and tedious process. They are best formed by means of wooden plugs, which are fixed before treads; the plugs are driven into the rough concrete before it is set, leaving them flush with the line of tread, so that when the topping is laid they will not be in the way. Plugs are best fixed by the aid of a wooden gauge. The gauge is made the same thickness as the topping, the length being equal to the distance between the nosing HOW TO USE THEM 411 mould and the riser board, and as wide as will admit of plug holes and the plugs to he driven through. The plugs are made a little larger than the baluster ends to allow for the lead. The gauge is laid on the rough concrete, using the returned nosing as a guide, and then driving the plugs flush with the top of the gauge. The gauge is then lifted up and laid on the next step, and so on until the finish. This method is accurate and saves measuring and marking the position of each hole on every step. When balusters are fixed on the ends of the steps, the plugs are fixed on the inside of the outer string. The plugs are generally left in until the balusters are ready for fixing. A ready method for forming “lewis” holes or other undercut sink¬ ings in concrete is performed by casting wedge-shaped blocks of plaster of the required form and size, and then laying them in the desired positions while the concrete is soft. When the concrete is set, the plaster blocks can then be easily cut out, leaving the under¬ cut sinking as desired. Summary of Staircases Constructed “in Situ .”—It will be seen from the foregoing that the operations em¬ ployed in the construction of concrete staircases formed m situ are: (1) setting out the stairs and landing; (2) fixing the wood framing; (3) gauging the materials and filling in; (4) removing the framing; (5) cleaning up the treads, risers and strings; (6) striking the soffit centring and finishing the soffits; (7) protecting and wetting the work until set and hard. Cast Steps .—Staircases are also constructed with steps cast separately, and then built in, in the same way as stone. Illustration No. 24 shows various sections of steps. Fig. 1 is a spandrel step, which may be used 412 CEMENTS AND CONCRETES for model dwellings, factories, etc. The tread is grooved to afford a good footing and prevent dipping. The dotted line indicates a square seating or tail-end of the step, which is embedded in the wall. Fig. 2 is a square step. Fig. 3 is a step with a moulded and returned Fig. i. Fig. 2. Fig. 3. Fig. 4. Sections or Steps, no. 24. nosing. Fig. 4 is a similar step, but having a moulded soffit. For cast work these steps must have a square seating or tail-end, as indicated by the dotted lines on Fig. 1, so as to bond into the wall. Treads and Risers .—Stairs between walls are some¬ times formed with treads and risers. The treads and risers are cast and built in as the construction of the work proceeds. Sometimes they are let into chases and pinned after the walls are built. Illustration No. 25 shows a section of treads and risers. HOW TO USE THEM 413 Closed Outer Strings .—Staircases are sometimes fin¬ ished with a close outer string, which prevents dirt or wet falling into the well. Illustration No. 26 shows the section, Fig. 1, and the elevation, Fig. 2, of a moulding outer string. The dotted line at A indicates a dowel hole for the balusters. Outer strings, whether plain or moulded, are much stronger when formed in situ. This is best effected by fixing a reverse mould at each side, then filling in the space from the top. The top is finished by hand and the aid of a template. The dowel holes are formed as already described. Concrete Floors .—It has been mentioned that the Romans, in the time of Julius Caesar, were in the habit, of constructing their floors and roofs, as Well as their walls, of concrete. According to an article in Archaeolo- gia, the cementitious agent was pozzolana. The lime 414 CEMENTS AND CONCRETES was obtained by burning ‘ ‘ traverstine. ’ ’ The aggregate usually consisted of broken tufa for walls, of broken lava for foundations where great strength was re¬ quired, and of broken pumice where lightness was es¬ sential. The floors were generally constructed of large slabs of concrete, supported on sleeper brick walls. The upper surface was finished with a layer of finer concrete and mosaic. The roofs were made flat, rest¬ ing on brick pillars. The first known English patent fireproof construction was obtained by one Dekins Bull, in 1633; but as at that period patentees were not com¬ pelled to disclose what their patents covered, no de¬ scription of the materials and methods can be given. Up to the middle of the eighteenth century fireproof their great weight and cost, were seldom used. But towards the close of that century cast-iron girders and segmental brick arches were gradually coming into use where strength was essential. Up to a century ago plaster was largely employed as a floor material. In floors usually consisted of brick arches, but owing to 1778 Earl Stanhope invented pugging for rendering wooden floors fireproof. By this process fillets were paled to the joists at about one-third of the height. Laths were laid on the fillets and plastered above and below with a coat of lime and chopped hay. The under sides of the joists were then lathed and plastered in the usual way to form the ceiling. About the early part of the last century wrought iron joists were substituted for cast iron girders. Fox & Barret’s floor, designed about 1830, was the first in which an attempt was made to protect the exposed faces of the iron joists with a fire-resisting material. Hornblower’s floor is one of the earliest for resisting the effects of fire. Iron, bricks HOW TO USE THEM 415 and plaster are chiefly used in the French and Ameri¬ can systems. For the sake of simplicity and reference, concrete floors may he divided into three kinds: (1) “Joist floors,” in which the concrete is laid slid be¬ tween the joists; (2) “Tabular floors,” formed with fireclay tubes or hollow lintels placed between the joists and covered with concrete; (3) “Slab floors,” formed in one piece or slab. Portland cement concrete laid in situ on and between iron joists is extensively used for fire-resisting structures. Cast concrete is used for some parts of tabular floors. Cast concrete blocks are used for the ceiling surface, and as a support for the rough concrete floor surface. The blocks are hol¬ low, and have male and female dovetails on the sides. The ceiling surface of the floors and the outer surfaces of the partitions are finished with a thin setting coat of gauged putty or Parian. The chief objects of fire¬ proof floors are to render each floor capable of resist¬ ing the effects of fire, so that fire cannot be communi¬ cated from one floor to another, and by making the roof fireproof, to prevent the fire from spreading from one compartment to another; to gain additional strength, so as to avoid as far as possible lateral thrust on the walls, and to secure the building from attacks and effects of both dry rot and damp. There have been about a hundred patents for fireproof floors during the past generation, of which about five or six survive. Plaster Floors .—Plaster concrete, that is, plaster and broken bricks, or similar aggregates, also neat plaster, were at one time used largely for the formation of floors. The use of plaster floors, was common in some districts, and up to a century ago the rough plaster, known as “floor plaster,” was in general use where 416 CEMENTS AND CONCRETES gypsum was found in abundance. Plaster floors were rarely used on the ground level, because they could not resist moisture, which caused them to become soft and retain the damp. They were principally used for up¬ per floors. The gauged plaster was laid upon reeds. These reeds were spread upon the tops of joists, and over them was laid straw to keep the soft plaster from percolating through the reeds. The floors were about 3 inches thick, floated fair, and finished the following day. Wood strips were placed around the walls, and drawn out when the plaster began to set, to allow for the expansion of the plaster. The materials being so light, the timbers were less in size and number than those now in use. The joists were in some instances 314 inches by 2^2 inches, fixed wide apart, and sup¬ ported by small beams about 4J/ 2 inches by 3 y 2 inches. The undersides between the joists were made fair by plastering the reeds, but in the better class of work the joists were covered with reeds, and held in position with oak laths, and plastered. Bullock’s blood was used to harden the floors after they were dry. In some in¬ stances they were coated with linseed oil to increase their hardness. Their use is now practically super¬ seded bj r Portland cement concrete. Joist Concrete Floors .—For this form of floor the concrete is laid between, over and under the iron joists Beyond the supervision of the fixing of the centring and the gauging of the materials, little skilled labor is required. The rough concrete is laid between and partly under the iron joists, which are fixed from 3 feet to 5 feet apart, according to the span and strength of the joists. The centring is supported, or rather hung, by the aid of timber laid across the joists and secured HOW TO USE THEM 417 by bolts. The materials are generally Portland ce¬ ment and gravel, coke-breeze, clinkers and broken bricks, gauged in the proportion of 1 part of matrix to 5 of aggregate. Sand equal to one-third of the bulk should be added. Coke-breeze is weak, light and elastic, but combustible and porous. A mixture of gravel and breeze in equal proportions is better than either alone. The proportion of cement varies accord¬ ing to the span and class of aggregate. All other things being equal, the strength of concrete is influ¬ enced by the strength of the aggregate, so that it would take a greater proportion of cement to make coke-breeze concrete equal in strength to a concrete made with hard aggregate, such as granite, slag or brick. The upper surface of this class of floor may be finished with wood, tiles or fine concrete, as re¬ quired. Joist concrete floors have been largely used. This is principally owing to their supposed cheap¬ ness, but it is more than probable that, in the event of fire, they would be dear in the end, because the lower part of the flanges are barely protected from the effects of fire, as the concrete, being thin at these parts, and also on a comparatively smooth surface, would soon crack or scale off, and leave the flanges of the joists exposed to the ravages of fire. They are also more or less conductors of sound. Caminus concrete cement is an excellent material for the construction of fireproof ceilings and partitions. Caminus Concrete Cement .—This material is specially designed to produce a hard and practically indestructi¬ ble concrete for the construction of fireproof floors and walls. It is manufactured from a waste product, and all inflammable material, such as coke-breeze, being en- 418 CEMENTS AND CONCRETES tirely dispensed with, the concrete is thoroughly fire- resisting. It is lighter and much cheaper than Port¬ land cement concrete, and is perfectly free from ex¬ pansion and contraction whilst setting. It can be man¬ ufactured to set in a few hours, so that the centres can be struck the day after the floor is laid. It can be supplied in a ready aggregated condition, so that the bags may be hoisted direct to the floor where the con¬ crete is being laid, and gauged on the floor, thus sav¬ ing a great amount of waste, and also labor in handling, mixing and laying. Concrete Floors and Coffered Ceilings .—A method was patented by E. Ransom for decreasing quantity of material and yet obtaining equal strength in floors. The floor is divided by a series of beams at right angles to each other, so as to form a series of coffers in the ceiling. For instance, for a floor 12 inches thick, the floor proper would be about 4 inches thick, and beams about 3 inches thick and 8 inches deep—a rod of twist¬ ed iron being placed in the centre of the thickness, and near the lower surface of the beams. The beams are generally about 2 feet 6 inches from centre to centre. The method of construction is as follows: First, form a platform or centring; on this a series of core boxes 2 feet 3 inches is placed, 3 inches apart, so as to form a 3-inch beam. The core boxes must be tapered and their upper edges rounded, so that they will draw when the centring is struck. The size of the core boxes may be altered to suit the size and requirements of the floor. With regard to the iron bars, the inventor says: “It is of vital importance for the strength of the struc¬ ture that the iron bars be placed no higher in the beam than calculated for; that the longitudinal centre of HOW TO USE THEM 419 these bars should be at the lowest point; and it is ad¬ visable that the bars curve upwards slightly and uni¬ formly each way from the centre to the ends, so that the ends are from 1 to 3 inches higher than the cen¬ tres. By preparing the concrete bed on a correspond¬ ing curve, the natural sag of the bar, as it is being handled to its place, gives all the requisite facility to accomplish this purpose. No crooked or irregular twisted iron must be used; otherwise, when the strain comes upon it, it will perforce straighten and lengthen out, and weaken the structure in so doing. After placing the iron, the rest of the concrete is tamped in place, and the whole made to form a monolithic block. It is of vital importance that no stop be made in the placing of concrete from the time the beam is begun until the thickness of the beam is in place and a ‘through joint’ is made. The web and the thickness must be one solid piece of homogeneous concrete.” Combined Concrete Floors and Panelled Ceilings .—A combined floor and panelled ceiling may also be formed in concrete. This is executed as follows: First, form a level platform or centring, and on this fix the re¬ verse plaster mould, run and mitred, according to the design of the ceiling. The intervening panels are then made up with framing, and the concrete filled in the usual way, and when set the centring and reverse mould are removed, and the ceiling cleared off. If de¬ sired, a finely finished and smooth white surface may be obtained by coating the surface of the moulds and panels with firmly gauged Parian, or other white ce¬ ment, until about % inch thick, and when this is firm (but not set), the rough concrete is deposited in layers and tamped to consolidate the concrete, and unite it 420 CEMENTS AND CONCRETES with the white cement. The surface may also be fin¬ ished with fibrous concrete. The method of doing this, also for carrying out the above white cement process, is described in “Fibrous Concrete.” Concrete and Wood .—Concrete floors finished with flooring boards require special care to prevent damp or dry rot. There are various methods in use for fixing and keeping the flooring boards from contact with the rough concrete, one way being to fix wood fillets to the joists by means of wedges or clamps. Another way is to embed wood fillets or fixing blocks in the rough concrete, leaving them projecting above the level of the iron joists, to give a bearing and fixing points to the flooring boards; or fine coke-breeze, concrete or plas¬ ter screeds, may be laid at intervals on the rough concrete, onto which the boards are nailed. Fixing blocks, concrete or plaster screeds, are preferable to wood fillets, as they do not shrink or rot, and will better resist fire. All these methods leave intervening- spaces between the concrete and the boards, and unless thoroughly ventilated, they harbor vermin, dirt and stagnant air. Unless the wood is thoroughly seasoned, and the boards grooved and tongued, dust and ef¬ fluvia will find egress through the joints. A portion of • dust and water when sweeping and washing the floors also finds egress through the joists; and as the concrete will not absorb the water, or allow the dust to escape, they accumulate and become unseen dangers. These sanitary evils may be obviated, or at least reduced to a minimum, by laying the boards direct on the con¬ crete. This not only forms a solid floor with no inter¬ spaces, but admits of thin boards being used with as much if not greater advantage than a thick board. HOW TO USE THEM 421 There is no uneven springing between the joists, which causes friction and opening of the joints, and the whole thickness is available for wear. There is also less total depth of floor, consequently less height of building and general cost. Another important advantage of a solid floor is that it will resist fire better than one with hol¬ low spaces. It is here that the sponginess and elasticity of coke-breeze concrete as a top layer is of special service, and where it may be utilized with advantage. Owing to its being able to receive and retain nails, the boards can be nailed at any desired place. Wood blocks for parquet floors can also be bedded or screwed on the concrete surface. Flooring boards will lie even and solid on this surface, and if a thin layer of felt or slag-wool be spread on the concrete before the boards are laid, a firm and noiseless floor is obtained. Slag- wool is an imperishable non-conductor of heat, cold and sound, and it will not harbor vermin. If the work is in humid climate, the coke-breeze surface when dry should be coated with a solution of tar and pitch, to prevent atmospheric moisture being absorbed by the porous coke-breeze. Concrete Drying .—To prevent dry rot ft is of the ut¬ most importance that the concrete should be thoroughly free from moisture before the flooring boards are laid and fixed. The drying of concrete is a question of time, which depends upon the amount of water used for gauging, the thickness and the temperature. It may take from three days to three weeks or even three months. The drying can be accelerated by directing currents of hot air on the lower surface, or by laying some absorbent material, such as dry sawdust or brick dust, on the upper surface. As soon as the surface 422 CEMENTS AND CONCRETES moisture is absorbed, or the dry material lias no further absorbent power, it should be removed to allow the mass to be air dried. Another way is to lay the floor in two coats, and to allow one coat to dry before the other is laid. For instance, if the floor is to be 6 inches thick, the first coat is laid with rough, but strong concrete, the aggregate being the best available; but taking gravel and coke-breeze to be the most plentiful, it will be best to assimilate and combine the good qualities of each to equalize their defects by mix¬ ing them in equal proportions. If brick is plentiful, and broken to properly graduated sizes, it will give better results than gravel or breeze. The mixed ag¬ gregate is gauged 5 parts to 1 of cement, and laid 4^ inches thick, and gently but firmly beaten in situ, the surface being left rough to give a key for the second coat. The second coat is not laid until the first is dry, and consists of one part cement to 5 of sifted and damped coke-breeze, gauged stiff, and laid 1 y 2 inches thick, beaten in situ, ruled level, and any ridges being laid fair with a long hand-float. The moisture of the second coat, b}' reason of the density of the first coat, will only be absorbed to a small degree, while the greater portion will be taken up by the atmosphere, and enable the combined coats to dry sooner than if laid in one. The first coat should be laid as soon as the roof is on, so as to give all possible time for it to dry, and the second coat to be laid and dried before the flooring is laid. When coke-breeze is not avail¬ able for the second coat, use soft brick, broken to pass through a 3-16-inch sieve. The method of laying floors in two coats is only given as an alternative plan, and as an example of a process used in some parts. Greater HOW TO USE THEM 423 strength, as a whole, and more perfect cohesion be¬ tween the two coats, is obtained by laying the second coat as soon as the first is laid, or at least while it is green. Concrete Slab Floors .—The term, slab floor, is applied to a concrete floor formed in situ, and in one piece or slab. It must not be confounded with slab pavements, which are constructed with a number of small cast slabs. Slab floors are usually made without exterior iron supports, but in a few instances iron T pieces or bars have been used as internal supports. Bearing in mind the lasting properties of the old Roman slab floors, and the enormous strength of the modern exam¬ ples at home, which are unsupported by iron, and are practically indestructible, it seems strange that they are not in more general use, and that for some inexplica¬ ble reason preference is given to shrinking, rotting and combustible floors, composed of poor iron and tim¬ ber instead of the best work and material, which, if a lit¬ tle dearer at first, is infinitely superior and vastly cheaper in the long run. The great sanitary advan¬ tages and fire and damp resisting powers of concrete slab floors are the highest known. The construction of slab floors is simple, and similar in many respects to that already described for stair landings and ordinary concrete and joist floors. There are Several methods of supporting the floors, the first and most common being to leave a sand course or to cut a horizontal chase in the walls to receive the ends of the floors. The second is to lay the floors when the walls are floor high, and build the higher walls on it when set. This method, while making sound work, is not always prac¬ ticable or convenient, owing to the delay in building 424 CEMENTS AND CONCRETES while waiting for the floors to set. The third method is to build corbelled ledges in the walls, so as to carry the floors. The centring for slab floors should be per¬ fectly rigid, water-tight and slightly cambered towards the ceiling centre. This camber gives more strength to the floor, and lessens liability to crack when remov¬ ing the centring. If joists are not used, the centring is supported on wall boards and centre struts. An¬ other way which gives great additional strength is to form the centring level, but having all the edges at the wall rounded off, so as to form the floor like an in¬ verted sink or tray. The horizontal chases in this case should be made wider than the thickness of the floor to allow for a thickness of rim. The extra width of chase, which may be one or two bricks thick, according to the width of span, is made below the centring or line of ceiling, the angles being coved by rounding the edges of centring. The coved rim gives greater strength with a less thickness of floor. The cove may be left plain or used for a cove for a plaster cornice, or rough¬ ened and used as a bracket for the same purpose. The expansion of concrete floors having large areas, or where hot cement has been used, has been known to disturb the walls, causing cracks and displacement of brick and stone work. This may be prevented by isolating the floor ends from the walls. This is done by forming expansion partitions or linings in the chases, the linings being composed of slag, felt or wood shav¬ ings, straw, reeds or other compressible material. The chase should be sufficiently deep to allow for a com¬ pressible lining about IV 2 inches thick, and a fair bed for the slab floor. Care must be taken to leave a few half bricks solid at intervals, say from 3 to 4 feet HOW TO USE THEM 425 apart, to support the upper walls until the floor is set. Compressible linings may be used for floors supported on corbelled ledges; and when the expansion, and in many cases subsequent contraction, has finally finished, the linings can be taken out, and the vacant space filled up with fine concrete, or utilized as a ground key for cement skirtings. If girder or iron posts are iso¬ lated from the walls by means of compressible linings, the effects of expansion and sound are limited. In some instances a judicious use of iron may be made. For instance, large areas may be divided with three or four rolled iron joists, so as to form shorter spans or smaller bays. Joists tend to bind the walls together, and to serve as scaffold bearings for building the upper parts of walls. They may also be used for hanging the centring on instead of strutting, or as aids to the strutting. Joists may also be used as integral sup¬ ports at unsupported ends of concrete floors. They should be so fixed that the lower flanges are not less than 1 inch above the lower surface of the concrete. The whole strength of iron is brought more fully into use by fixing it near the lower surface. If fixed near the centre, or at the axis of neutral stress, a correspond¬ ing part of the strength is comparatively of little value. Construction of Slab Floors .—Portland cement as a matrix is indispensable. The unequal nature of gravel and coke-breeze renders them unfit and unsafe aggre¬ gates for this class of work. Broken brick being cheap, and obtainable in most districts, affords a ready aggre¬ gate, and may be used with safety and success. In ordinary cases of concrete construction, the whole thickness is usually made with one rate of gauge; but 426 CEMENTS AND CONCRETES for slab floors covering large areas, and unsupported by iron or other supports, exceptional strength is re¬ quired. Stronger results are obtained by making up the whole thickness with different rates of gauge. Tak¬ ing the usual gauge for floors as from 4 to 5 parts of aggregate to one of cement, and used for the whole thickness, it gives an unequal strength, a part of which is comparatively of little use, especially at the neutral axis; but if the cement is divided so as to form an ordinary coat in the centre, and stronger coats at the upper and lower surfaces at the points of greatest strain, the upper being compressive and the lower ten¬ sive, a better and more accurate arrangement of strength and allowance for disposition of strains is ob¬ tained. The additional strength at the proper places is obtained not only by the use of additional cement, but by the method of construction, which enables the same quantity of cement as gauged for the usual rate for forming the whole thickness in one coat to be used more profitably. Take the section of an iron joist as an example; this gives divided yet united strength, which sounds paradoxical, but is true. The flanges sustain the greatest strains, and the web comparatively little. With con¬ crete, the strong coats at the upper and lower surfaces represent the flanges, and the ordinary coat the web. As already stated, the increased and profitable dis¬ tribution of strength is obtained by the method of con¬ struction. For instance, take a slab floor 20 feet by 14 feet and 12 inches thick, without iron joists or other supports, and intended to carry a safe load of 2 y 2 cwt. per superficial foot, in addition to its own weight of say 1 cwt. per square foot. This floor is laid in three coats, HOW TO USE THEM 427 the first composed of 1 part cement and 2 of fine broken bricks gauged stiff, and laid 2 inches thick; the second composed of 1 part cement and 6 of coarse broken bricks gauged stiff and laid and rammed 8 inches thick; and the third composed of 1 part cement and 2 of fine broken bricks gauged stiff and laid 2 inches thick. If the upper surface is intended for hard frictional wear a slight difference is made in the gauge and materials. The first coat is composed of 2 parts of cement and 5 of fine broken bricks gauged stiff and laid 2 inches thick; the second of 1 part cement and 6 of coarse broken bricks gauged stiff and laid and rammed till 8 inches thick; and the third eoat composed of 1 part cement and 2 of fine crushed slag or granite. It will be seen that this constructive method gives the desired positions of strength, and the total quantity of cement in the united gauges is 1 part to 4, and up to 5 parts of aggregate. The fine broken bricks should be passed through a %- inch sieve, and the coarse through a 2-inch screen, taking care that the latter contains a greater quantity of the smaller pieces than of the larger. It must be clearly understood that the second coat must be laid before the first is set; also that the third is laid before the second is set, so as to ensure perfect cohesion be¬ tween each coat, and the absolute homogeneity of the whole mass. Hollow Floors .—Greater lightness in concrete floors is obtained by the use of concrete tubes. If the tubes are placed apart and in the centre of the floor thickness, a hollow homogeneous concrete slab is formed. The vertical divisions between the tubes connect the upper and lower coats, as with a web of a joist connecting the upper and lower flanges. The method of construction 428 CEMENTS AND CONCRETES is simple and expeditions. For example, for a slab floor 10 inches thick, first lay a coat 2 inches thick of the stronger and finer concrete, as described for the 12 -inch slab floor, and when this is firm lay 5 or fl¬ inch tubes from wall to wall. Bed the sides with rough concrete, and lay another row of tubes parallel with the first row and about 2 inches apart, and so on until the floor area is covered; then make up interspaces with rough concrete till level with the upper surfaces of the tubes, and then cover this with a coat of fine concrete 2 inches thick. Concrete tubes or common earthenware drain pipes may be used. Half-circle pipes, laid on their side edges, may be used to save concrete and weight in joist floors, etc. Concrete Hoofs .—Concrete roofs require special care to render them watertight. Subsidence in the brick work of new buildings is often the cause of cracks on concrete roofs. The roof should have a good camber, to give greater strength and allow for the fall of wa¬ ter to the outer edges. The rough coat should be laid and well consolidated by ramming or beating, and then left for seven days (the longer the better) before the topping is added. The upper coat should be strongly gauged with fine aggregate, as in “Eureka.” If possi¬ ble, the topping should be laid in one piece. If the area is too large to be laid and finished in one piece, the joints of the bays should overlap. This is done by rebating the screed rules, so as to allow one-half of topping thickness to go under a part of the rule and form an underlap or ledge about i /2 inch wide, and when the adjoining bay is laid an overlapped but level joint is the result. Roofs exposed to the sun’s heat should be kept damp for several days after being laid, HOW TO USE THEM 42y as joints are affected by the heat as well as by deflec¬ tion of centring or subsidence of walls. Compressible linings or wood strips should be used round the walls to counteract any expansion. All concrete roofs should have a cement skirting 6 inches high and 1 inch thick well keyed into the walls. If linings are not used when the topping is laid, the topping should be turned up on the walls, so as to form a rim, to prevent water get¬ ting between the roof and the walls. Greater heat and damp-resisting powers are obtained by laying the up¬ per surface with %-inch thick coat of special concrete, composed of 1 part of Portland cement, part of slaked lime and 1 part of firebrick dust. This should be consolidated with a hand-float, and finished fine and close with a trowel. Notes on Concrete .—When calculating the strength of floors, stairs, etc., the following facts should be borne in mind: Portland cement, when new, is too hot; sets more rapidly and expands more than old cement. The finest ground cement is the best and strongest. The time in setting, and in which the maximum strength is attained, varies according to the age of the cement, the quantity of water used, and the mode of gauging and the mean atmospheric temperature. The maximum strength of a briquette of mature cement is maintained, while one of new cement “goes back.” A briquette of matured cement will stand a tension strain of 550 pounds per square inch, and a crushing weight of 6,000 pounds per square inch. A briquette of neat cement is more brittle than one of concrete. Briquettes mature more rapidly than thick slab floors. The adhesive strength of Portland cement is about 85 pounds per square inch. The adhesive strength increases more 430 CEMENTS AND CONCRETES rapidly than the cohesive. A mass with a surface large in proportion to its volume sets more rapidly than a mass with a small area in proportion to its volume. Masses subject to pressure set more rapidly and attain greater hardness than masses not so pressed. The average compressive strength of concrete is about eight times its tension strength. The proportion of com- pressional and tensional strength varies according to the quality and quantity of the aggregate. The strength of concrete depends greatly on the proportion of the matrix and aggregate; also on the strength of the lat¬ ter. As regards bricks, it must be remembered that there is a wide difference between the tensile strength of hard, well-burnt bricks and soft stocks. No bricks are so strong as cement, the best kinds being about one-fourth the strength of neat cement. Taking the gauge as one part of cement to 4 of broken brick, the strength of the concrete will be about two-fiftlis of neat cement, but for safe and practical calculations it will he best to take the strength as one-fourth of neat ce¬ ment. Square slabs are stronger than rectangular slabs. Slab floors being homogeneous throughout, the whole weight is a dead weight, and consequently there is no thrust on the walls. With regard to the live load or weight which floors should he constructed to carry, some difference of opinion exists. Hurst says that for dwellings 1% cwt., public buildings ^2 cwt. an d ware¬ houses and factories 2 y 2 cwt. are safe calculations. Others assert that for domestic buildings 1 cwt. per foot would be ample for all contingencies. An American authority states 40 lbs. is sufficient for ordinary pur¬ poses. The following table shows the results of tests HOW TO USE THEM 431 of slab floors made without iron. The slabs were sup¬ ported all round, and uniformly loaded with bricks. Test of Slab Floors. No. Length between Sup¬ ports, feet. Breadth between Sup¬ ports, feet. Thick¬ ness, feet. Age in Days. Breaking Weight, in cwt. per sq. ft. Weight of Slab, in cwt. per sq. ft. Total Breaking Weight, in cwt. per sq. ft. 1 14.5 6.75 .5 7 3. .54 3.54 2 ( < < < < < 14 2.76 < < 3.30 3 < < (( < < 21 8.88 < < 9.42 4 t < 13.5 < < 7 1.07 U 1.61 5 ( < 6.75 < 6 14 2.51 < ( 3.05 6 < < < C ( < 21 2.84 ii 3.38 Cast Concrete .—Innumerable patents have been ob¬ tained for a combination of materials, also moulds for the construction of artificial stone. Among the many that may be mentioned is Mr. Ranger’s system. He obtained a patent in 1832 for artificial stone formed with a lime concrete. The aggregate consisted of shingle, broken flints, mason’s chippings, &c. The in¬ ventor stated that the best results were obtained by using 30 lbs. of an aggregate of a siliceous or other hard nature, 3 lbs. powdered lime, and 18 ozs. boiling water. No more of the materials were gauged at the time than were sufficient to fill one mould, as the boil¬ ing water caused the concrete to set very rapidly. This material, after fifty years’ exposure is still sound and shows no sign of decay. No artificial stone equals, far less excels, the strength and durability, sharpness, and evenness of Portland cement concrete. This form of artificial stone is now extensively used as a substitute 432 CEMENTS AND CONCRETES for natural stone, for window heads, string courses, sills, columns, copings, keystones, and many other archi¬ tectural, constructive, and decorative features. Fig¬ ures, animals, bas-reliefs, capitals, panels, can be made in fine concrete with all the relief, undercut, and fine detail which distinguishes high-class from inferior work. Cast work has the advantage over in situ work that any defect can be detected previous to fixing. The methods of moulding and casting various works are given in the following pages. Concrete Dressings .—Architectural works, especially large or plain parts, are generally cast in wood moulds. If there are ornamental parts in the blocks, a combina¬ tion of wood and plaster, and sometimes gelatine, is used for the moulds; wood for the main or plain parts, plaster for circular or moulded parts, and gelatine for undercut parts. The plaster or gelatine, as the case may be, is screwed on or let into rebated parts of the wood. Ornamental parts are sometimes cast separately, and then fixed on the main cast. They may also be cast separately and laid into the main mould (face inwards), and the whole is cast together in a somewhat similar way to that described for “bedded enrich¬ ments” in fibrous plaster cornices. Considerable skill and ingenuity has been displayed in the construction of wood moulds for casting concrete blocks for architectural purposes. Many methods have been employed for fixing the sides and ends together, and also to the bottom of the mould, leaving one or more parts unfixed to facilitate the release of the cast. The primitive method is to fix the various parts of the mould with screws. This is a slow and unreliable process, as the continual screwing and unscrewing for HOW TO USE THEM 433 each cast soon wears the screw-holes, and the sides be¬ come loose and out of square, causing the casts to get out of their true form. Hinges, also hooks and eyes, have been used for the same purpose, but they are liable to the same defects as the screws when subject to long use. -Wedge Mould for Casting Blocks, Moulded Lintels, &c. no. 27. Thumbscrews to fit into iron sockets are also used, but they are too expensive for ordinary work, and are unsuitable for small moulds. One of the most simple and reliable methods is the “wedge mould,” invented by an architect. It is easily made, and expeditious in working. Even after long and constant use, the casts are always accurate in form and size. The wedges and the rebated ends allow the various parts to be correct¬ ly fixed and held in position. Illustration No. 27 shows the method of construction. The various parts are 434 CEMENTS AND CONCRETES named, and the sketch is self-explanatory. When the moulds are extra deep, it is necessary to make two or more sets of tenons and wedges at each angle. When there are a large number of casts required the mould ends are strengthened by binding the projecting ends with hoop iron. This method has been adopted for casting a lot of blocks. Illustration No. 28 shows two useful kinds of moulds. Fig. 1 is a simple form of mould adapted for plain blocks, caps, lintels, &c. A, A, are the sides, which are grooved into the ends B, B, and Fig. i. Fig. 2. NO. 28. held together by the bolts and nuts, C, C, two on each side. The bolts may be about % inch diameter, with a good-sized square-head at one end, and a washer and nut at the other. This, having no bottom, is termed a bolted frame mould. It should be laid on a bench or moulding board before the cast is filled in. Fig. 2 is a section of a combined wood and plaster mould on the wedge principle, adapted for casting a strong course moulding. A is a moulding board, l 1 /? inches thick, formed with two or more boards; a is one of two or more cross ledges, 1 inch thick, on which A, the ground, is nailed. B is a width board, 1 inch thick, which is HOW TO USE THEM 435 nailed on to A. This gives a point of resistance to the plaster piece C and the side board G. D is a side board cm which E is screwed. E forms the sloping part of the weathering. F is one of two or more vertical wedges which hold D E in position. The sockets for the wedges F are made between the cross ledges, so that the wedge will project below the ground A. This allows the wedges to be more easily driven out when the cast is set. G is the back or plain side board. II is a fillet, l 1 /^ inches square, screwed on to the ground A. I and J are two folding wedges, or, in other words, wedges driven in opposite directions. These hold G in position. Two or more of these folding wedges are required, according to the length of the mould. The same remarks apply to the vertical wedges F. The lat¬ ter form of wedge is only given as an alternative. The end pieces are held in position by dropping them into grooves in a similar way as shown in the previous fig¬ ure, with the exception that the grooves are cut in the sides instead of the ends. K is a gauge rule which is used for ruling the upper surface of the cast fair. This may also be done by working a straight-edge longi¬ tudinally. The dotted line at L, the concrete, indicates the wall line. The level part of the weathering up to this line, or if splayed from the outer member of this line, must be finished smooth to allow the water to run freely off. When the cast is set, the wedges are with¬ drawn, and the sides and ends released. The cast is then turned over on its back end or top side on a board, and then the plaster piece and the wood ground is taken off. If the cast is green, it should be turned over on old sacks or wet sawdust, so as to protect the arrises, and avoid fractures. 436 CEMENTS AND CONCRETES Illustration No. 29 shows a method commonly adopted for constructing moulds for sills and copings. Fig. 1 is the section of a mould for a window sill. A is the moulding board, made with two or more pieces, each 114 inches thick; a is one of two or more cross ledges, made with 1 inch stuff, on which A is nailed. B is the width board, made of % inch stuff, nailed on to A. C is a block, 1% inches thick, which is nailed on to B. These blocks are placed about a foot apart, or so that they will carry the lining D, 1 inch thick. A F'g: » Fig. 2. Fig. i.—Section of Mould for Casting Sills. Fic. 2.—Section of Mould for Casting Coping. NO. 29. groove or an iron tongue E is made in B, and a piece of thick hoop iron or iron bar is placed loosely in the groove before the cast is filled in. F is a fixed side, 1 Vi inches thick. G is a fillet, 1 y 2 inches square, nailed on to F, and screwed on to moulding board A. H is a loose side, 1*4 inches thick, on which the fillet I is nailed. J is one of two or more clips, which turn on a screw, and are used to hold the loose side H in posi¬ tion. These clips are made and used in the same way as described for fibrous slabs. As compared with wedges, clips are always in position ready for use, are HOW TO USE THEM 437 not liable to be mislaid, and when the fillets are fixed on to the side pieces, the clips keep the sides from rising as well as expanding. K is a throating or water groove, which is formed in the concrete L, with a rule having a rounded edge. Two blocks, dished at the inner ends, must be fixed one at each end of the mould, so as to form a stool or bed for the superstructure. The position and form of the groove is obtained from sink¬ ings cut in the end pieces of the mould. The end pieces are held in position by grooves cut in the side pieces in a similar way, as already described, with the excep¬ tion that the grooves are cut in the side pieces, instead of the end pieces. When setting out the mould, an extra length must be allowed for the side pieces for the grooves. A part of the upper surface of the cast (be¬ ing the part which projects beyond the line of wall) must be finished fair by hand at the same time as form¬ ing the water groove. This must be done while the cast is green. When the cast is released from the mould, the iron tongue will be found firmly embedded in the concrete. Fig. 2 is a section of a wood mould adapted for casting wall copings. A is the ground of a mould¬ ing board, which may be made of 114 -inch stuff, and in 2 or more widths; a is one of two or more cross ledges, 1 inch thick, on which A is fixed. B, B, are blocks about l 1 /^ inches thick, placed about 1 foot apart. C, C, are linings, 1 inch thick, nailed to B, B. D is a fixed side, 144 inches thick. . E is a fillet, l 1 /} inches square, fixed to D, and then screwed on to A. F is a loose side, 1^4 inches thick, on which is nailed the fillet G, 1 Yz inches square. This strengthens the sides and affords the fixing point for the clip H. The water grooves I, I, and the hollowed part in the middle of the 438 CEMENTS AND CONCRETES concrete J (made to save materials in weight) are worked from the end pieces of the mould, which are let into the grooves, as described in the previous diagram. If the moulds are deep, wood , or iron clamps may be fixed across the sides to keep them in position, as shown by K. The moulding boards in this and the previous figures, if strongly made, can be used for a variety of similar purposes. When introducing cast instead of run moulded work, I used iron and zinc plates to strengthen and make more durable plain surfaces on wood moulds; but owing to the expense and trouble in fixing the plates to the woodwork, they were aban¬ doned, and by using a better class of wood, and in¬ durating the surface of the mould with hot paraffin wax, sharp and clean casts were more cheaply pro¬ duced. Cast-iron moulds may be used where there is a large number of casts required. They may also be advantageously used for stock designs, such as plain moulded balusters. Wood moulds are rendered more durable and impervious to wet by brushing them with hot paraffin wax, and then forcing it into the wood by ironing with a hot iron. The use of paraffin wax and oil has already been described. Mouldings Cast “In Situ . ,, —Casting cornices, cop¬ ings, &c., in situ is now frequently employed for con¬ crete. The advantages of this system over shop cast work, are, that the work is readily done, and the cart¬ age or moving from the workshops to the building, and the fixing, are dispensed with. Illustration No. 30 shows the method of constructing and fixing various kinds of casting moulds for in situ work. Fig. 1 shows the section of a cornice, casting mould, Fig. I.— Combined Plaster and Wood Moulds for a Cornice. Fig. 2. —Wood Mould for String Mouldings. Fig. 3.-^Mould foi Coping. Fig. 4.—Mould for Saddle-back Coping. Fig. 5.—Mould for Coping with Chamfered Angles. NO. 30. 440 CEMENTS AND CONCRETES and supporting bracket. Wood moulds are generally used for small or plain mouldings, but where the profile is undercut or of an intricate nature, a plaster mould is preferable, as it is easier and cheaper to construct a plaster mould than cut the irons which are necessary for a wood mould for a special design. Fibrous plaster moulds may be used for this class of work, but to illus¬ trate another method a combined wood and plaster mould is given. M is a moulding board to strengthen the plaster profile, and on which it is run. The board may be made in two or more pieces, each about 1 inch thick, and in width according to the depth of the mould¬ ing, and in length as required, the whole being held together by cleats H, which are nailed about 3 or 4 feet apart. Broad-headed nails are then driven in at ran¬ dom, leaving the heads projecting, to give a key for the plaster profile P. The profile is then run with a reverse running mould. It will be seen that this profile is undercut, therefore a loose piece L is required to enable the mould to draw off the moulding. The re¬ verse mould and loose piece are constructed in the same way as described under the heading of “Reverse Mould¬ ings.” It may be here remarked that it is sometimes useful to have an “eye” inserted in the loose piece to give a better hold for the fingers when taking the loose piece off the moulding. The eyes are made by twisting a piece of strong wire round the handle of a tool bruch, leaving one end in the form of a ring, and the other bent outwards so as to form a key. The eyes are fixed about 3 or 4 feet apart, the fixing being done by cut¬ ting a hole in the loose piece and bedding the shank of the eye with plaster, and then cutting a slot in the main part of the mould to receive the ring of the eye IIOW TO USE THEM 441 as shown at E. The mould is held in position by the bracket B, fixed 4 or 5 feet apart. The mould is further secured by the stay S, the other or inner end of the stay is fixed on to the main wall. It will be understood that a plaster mould for this purpose should be dry and hard, and then well seasoned with linseed oil, or with a hot solution of paraffin wax. After the mould is fixed in position it is oiled, and then the concrete C is filled in, taking care that the surface of the mould is first covered with a thin coat of neat cement. The mould may be oiled with paraffin oil; but if the mould is in¬ clined to “stick,” oil it with “chalk oil,” i. e., paraffin oil and French chalk, about the consistency of cream. When the concrete is set, the brackets are removed, and the mould taken off. The mould in this case would draw in the line of the arrow A. The loose piece is then taken off. It is here that the use of the eyes will be found. Before removing the brackets it is advisable to prop the mould, in case it may drop olf and break the fragile portions of the mould or parts of the cornice. A heavy mould hanging in this position, especially if the profile is flat, or in good working order, is apt to drop, hence the necessity of props. If the mould clings, or, as more generally called, “sticks fast,” gentle tap¬ ping with a heavy hammer will ease or spring it, and allow it to be taken off. A heav}^ hammer is more ef¬ fective in making the mould spring than a light ham¬ mer, as the force required for a light hammer is apt to injure the mould. This is why a heavy hammer with a flat head is best for plaster piece moulding. Fig. 2 is the section of a string moulding with the casting mould and bracket. A chase is formed in the brickwork to allow it to bond, and the joints and the 442 CEMENTS AND CONCRETES surface of the brickwork are cut, out and hacked to give a further key to the moulding. M is the mould (in this case made of wood). The profile is drawn without any undercut parts, so as to allow the mould to draw off in one piece. B is the bracket, and C is the concrete. The same directions for casting Fig. 1 apply to this and the other moulding here shown. A drip member, as shown at the top member of both cornices, is generally used for exterior mouldings, to prevent the water run¬ ning over the wall surface. Fig. 3 is the section of a wall coping and the casting * mould. M is the mould, a similar one being used for the other side. A mould for this purpose is best formed with flooring boards about 1 inch thick, and fixing them together as shown. The drip D is readily formed by sawing an inch bead through the centre, and nailing it on the bottom. Two forms of brackets, B and B, are here given. One is cut out of the solid, and the other made of two pieces of wood nailed together. Fig. 4 is the section of a casting mould for a saddle¬ back coping. R is a quarter-round piece of wood fixed in the angle of the mould to form a cavetto, which is sometimes used in copings. D is an angular-shaped drip, sometimes used in place of a circular one. T is part of a template used for forming the saddle-back of the coping. Fig. 5 is the section of a mould for a coping with splayed or chamfered angles. S is a triangular strip of wood fixed in the angle and the top of the mould to form the splays, and D is a circular drip. Concrete mouldings that are deeply undercut or in¬ tricate in profile may be cast in situ by the use of the “Waste Mould Process.” HOW TO USE THEM 443 Modelling in Fine Concrete .—Figures of the human and animal form, also emblems, trade signs, and build¬ ings, are now being made in fine concrete. The work may be executed in situ, or in the moulding shop, anti then fixed in position. For important works a plaster model is first made, and placed in position, so as to judge of the effect before committing it to the perma¬ nent material. For this purpose the model is first modelled in clay, and then it is waste-moulded, and a plaster cast obtained. After the model is approved it is moulded, and then cast in the fine concrete. The material is composed of Portland cement, and a light, but strong, aggregate; and the cast is made in a similar way to that described for casting vases. The material may be colored as required to suit the subject. The general method of executing figures “on the round” in fine concrete or Portland cement is to model the figure direct in the cement on an iron frame, and then to fix it in its permanent position. This is effected bj^ first making a full-sized sketch of the proposed figure, then setting out on this the form of the necessary iron¬ work to serve as frame or skeleton to form an internal support. This iron frame also forms a core to enable the figure to be made hollow, and serves as a permanent support for thin parts and extremities of the figure. The quantity, size, and form of the iron frame is regu¬ lated by the size, form, and position of the figure. For instance, if the model of a full-size lion is required, first make a rectangular frame to suit the feet of the lion and the base on which the figure stands. The base frame is made of iron bars, IV 2 inches wide by ^4 inch thick, fixed on edge. Then set out four leg-irons, and connect them on the base frame, and then set out one 444 CEMENTS AND CONCRETES or two body-irons, and connect them with the leg-irons. After this set out a looped piece to fit the contour of the neck and head, and fix it to the body-iron. Now set out the tail-iron. This is best formed with an iron pipe, and it should be made to screw on to the body- iron. This allows the tail to be unscrewed when the model is finished, and screwed on after the model is fixed in position, thus enabling the model to be more freely handled, and with less risk of breakage when moving and fixing in its permanent position. Having made the frame, place it on a stout modelling board, keeping the base frame from 1 to 3 inches above the board, according to the depth of the base; the frame being temporarily supported with four pieces of brick or stone. This is done to allow the base frame to be enveloped with concrete. This done, fix wood rules, cut to the depth of the base, on the board, so as to form a fence on all sides of the base. Then fill in the base with concrete; and when this is set, proceed with the coring out, so as to obtain a hollow model. In order to decrease the weight of concrete figures “on the round,” and to enable them to be more easily handled and hoisted when fixing them in their perma¬ nent positions, they should be made hollow. This is effected by making a round skeleton frame with hoop- iron, or with wire-netting, for the body, neck, and head, and other thick parts. This metal skeleton must be built on and securely fixed to the main iron frame. The whole, or parts of the figure, may also be cored out with shavings or tow, and held in position with tar bands or canvas strips, dipped in plaster. Tow is an excellent material for forming cores. By making up the inner parts with dry tow, and then dipping tow in plaster for HOW TO USE THEM 445 the outside coat, the core can be made to any desired shape, and also leave the necessary thickness for the concrete. To prevent the material slipping down by its own weight, pieces of iron or wood, in the form of crosses, are fastened with copper wire or tar rope to the iron rods, which are used as single supports. These iron or wood pieces must be fixed in all directions, and in such a way that the material is held up by them. For small extremities, such as fingers of human figures, beaks of birds, fins of fishes, horns and tails of animals, iron rods should be fixed on the main frame, and the parts to be covered with cement must be notched or bound at intervals with copper wire or tar rope. The distance between the core and the finished face of the figure is of course the actual thickness of the model. This thickness may vary from 1 inch to 3 inches, or even 4 inches at some parts. An actual thickness of 2 inches will be sufficient to give the requisite strength. When the core is made, cover it with a coat of Port¬ land cement arid old lime putty, in the proportion of 3 of the former to 1 of the latter, and add sufficient tow or hair to give tenacity. If there are open spaces in the skeleton iron work, bridge them over with bits of tiles and cement. The whole surface, after being coated, must be Avell scratched with a nail, to give a key for the roughing out coat. This scratched coat must be allowed to set before proceeding with the actual model¬ ling. The stuff for roughing out is composed of 2 parts of Portland cement and 1 part of fine aggregate. Crushed bricks, stone, or pottery ware passed through a sieve having a % inch mesh may be used as aggre¬ gates. The finishing stuff is composed of fine sifted Portland cement. The addition of a fifth part of old 446 CEMENTS AND CONCRETES lime putty to the cement makes the stuff more mellow, and works freer and sweeter. The modelling is done as described for in situ work. The finishing coat can be colored to any desired tint, as already described. Concrete Fountains j >—Fine concrete is an excellent material for the construction of fountains. It is ob¬ vious that a vast amount of cutting and consequent waste of material is involved in the executing of foun¬ tains, “on the round,” when natural stone is employed. Saving of material, and a corresponding reduction in the cost, is effected by use of a material that can be easily cast, and is at the same time durable and im¬ pervious. These qualities combined are found in arti¬ ficial stone composed of fine concrete. Being readily made in large blocks (any sized basin can be made in one piece), there is no jointing required, as is the case with terra cotta, which is another form of artificial stone. Fountains composed of fine concrete are made in a similar way to that described for making and cast¬ ing vases. Concrete Tanks .—Concrete tanks to contain water, and for a variety of manufacturing purposes, are now largely in use. They are strong and durable, and hav¬ ing hard smooth surfaces, they are easily washed and kept clean. Being impervious to vermin, damp, and atmospheric influences, they are the coolest and most sanitary water cisterns that can be used. Cattle troughs are best made in concrete. Concrete tanks have been used as water and silicate baths for indurating con¬ crete casts, and during their constant use for over a decade no signs of cracks or damp are visible. Thej^ were made in one piece, varying in size from 6 feet uf to 18 feet long, 3 feet to 7 feet wide, 2 feet 6 inches to HOW TO USE THEM 447 4 feet high, and from 3 to 4 l /2 inches thick. Some were cast, but the large ones were made in situ. The method of construction (for in situ work) being simple and ex¬ peditious, the total cost is small. For a tank 9 feet long, 4 feet 6 inches wide, 2 feet 6 inches high, and 3y> inches thick, first frame up wood sides and ends to the above length, width, and height, then make inside boards, the lengths and widths being the same as above, less the tank thickness, and the heights less the bottom thickness. The sides and ends are hung by means of cross battens laid on the upper edges of the outside framing, and kept in position with inside stays. This leaves an open and continuous space at the sides, ends, and bottom. The constructive materials are 1 part of Portland cement and 2 of fine slag or granite, gauged stiff, and laid over the bottom. Next, the open sides and ends are filled up, taking great care that the whole mass is thoroughly consolidated by ramming. The stuff for the sides and ends should be laid in layers from 6 to 8 inches deep, each layer being well rammed before the next is laid. The angles are strengthened by inserting angle irons during the process of filling in. As soon as the concrete is set the inner boards are removed, and if the surface is smooth or dry, it must be keyed with a coarse drag or a sharp hand pick. It is then swept and wetted to cleanse it and stop the suction, so as to ensure perfect cohesion, and allow the final coat to retain its moisture during the process of trowelling and the stuff setting. The finishing coat is composed of neat cement, the finer ground the better, as percolation through con¬ crete made with a finely ground cement is less liable than when made with a coarsely ground cement. 448 CEMENTS AND CONCRETES The final coat is laid about 3/16 inch thick, and pre¬ ceded by brushing the surface with liquid cement to fill up all crevices, and afford better adhesion between the surface and the final coat. When the stuff is firm, it is well trowelled to a fine and close surface. The outer boards are then removed, and the surface finished in a similar way. Concrete Sinks .—Concrete sinks can be made to any desired size or form. They are cast in wood or plaster moulds, and are composed of 1 part of Portland cement to 2 parts of fine crushed granite or other hard aggre¬ gate. They are made with rebated holes for traps. The ordinary size are as follows: 2 feet 6 inches by 1 foot 8 inches; 2 feet 9 inches by 1 foot 8 inches; and 3 feet by 2 feet, all 6 inches deep, and from 2 to 3 inches thick. Garden Edging .—Plain and ornamented edgings are now made in concrete. They are made in various lengths. The most useful size is 3 feet long, 6 inches deep, and 2 inches thick. They can be made to any curve, and tinted to any shade. Concrete Vases .—During the last half-century thou¬ sands of vases, composed of fine concrete—commonly called ‘'artificial stone’’—have been used for the dec¬ oration of buildings and practical use in gardens, con¬ servatories, &c. For vases that are cast in sections the thickness of large and open parts, such as the “body,” are regulated by means of a plaster core, which is placed in the open mould. The contour of the core must be so arranged that the cast will draw from the core, or vice versa. For some forms of vases, the core must be made in pieces similar to a piece mould. The method of making, moulding, and casting—the latter by the aid of a template instead of a core. HOW TO USE THEM 449 Concrete Mantel Pieces. —Chimney-pieces of all sizes and shapes are now extensively made in fine concrete. They are generally made in wood moulds, plaster moulds being let in the main mould for ornamental parts. They are often made in colored concrete. Colored Concrete .—Concrete casts, also work laid in situ, can be colored to imitate any natural stone. This is effected by mixing mineral oxides of the required color with the cement used for the surface coat. The color coat should not exceed Vs in thickness, as oxides are too expensive to use for the entire thickness of the cast. The quantity of oxide to be added to the cement depends upon the strength of the oxide. Some are much stronger than others. Five per cent, of a strong oxide will impart a close resemblance of the desired color to the concrete, but a weak oxide will re¬ quire from 10 to 15 per cent., and even 20 per cent., to obtain the same color. Some of the red oxides range in color from scarlet or Turkey red, gradually deepen¬ ing to chocolate. Some oxides contain 95 per cent, of pure ferric oxide, which is made from copperas, or, scientifically speaking, sulphate of iron. This is a by¬ product, and is frequently evolved from waste acid liquors at tinplate works, and is obtained in large quan¬ tities from South Wales. This kind of oxide is far more suitable for coloring concrete than ochres and most of the earthy oxides. Earthy colors, like Venetian red and umber, soon fade and have a sickly appearance. The oxides should be intimately mixed with the cement in a dry state before it is gauged. The mixing is gen¬ erally done by hand, but better results are obtained by the use of grinding machine. It is a safe plan to try various proportions of color and cement and gauge 450 CEMENTS AND CONCRETES small parts, and when set and dry select those most suitable for the desired purpose. All cast work, as soon as extracted from the moulds, should be examined, and any blubs stopped and chipped parts or other minor defects made good while the work is moist or green, using neat cement and colors .in the same proportion as used for the surface stuff. Colored surfaces may be greatly improved by brushing the cast as soon as set with a solution of the same color as used for the sur¬ face coat. A color solution, made by mixing the color with water and a solution of alum, is very useful for coloring Portland cement, with or without sand. If this coloring solution is brushed over the surface while it is moist or semi-dry, a good standing color can be ob¬ tained without mixing color with dry cement. This method will be found useful for sgraffitto, &c. A novel and color-saving method, for coloring the upper surfaces of slabs or other flat casts, is effected by first filling in the mould in the usual way, then placing the colored cement in a dry state in a hand sieve, and then violently shaking or tapping the sides of the sieve, so as to sprinkle the colored cement uni¬ formly over the surface until it is nearly 1/16 inch thick. The surface is then trowelled in the usual way. The sprinkling must be done as soon as the main body of the stuff is ruled off, so as to obtain a homogeneous body. Another and a novel method which may be ad¬ vantageously employed for finishing slab or other large surfaces in a mould is as follows: A fine finished face is more readily obtained by using a smoothing knife (for brevity termed a “shaver”) than by a trowel. A shaver is a piece of polished steel about 3 inches wide and % inch thick, the length being regulated according HOW TO USE THEM 451 to the width of the mould, and allowing about 8 inches at each end for handles. For instance, for a slab 2 feet wide, the shaver should be 3 feet long. This allows 2 feet for the surface of the cast, 3 inches to bear on the rims of the mould, each 1V> inches wide; 8 inches for the handles, each 4 inches long; and 1 inch for play. One edge or side is cut to an angle of 45°, so as to form a cutting edge. The method of tilling in, coloring, and finishing the surface of the slab is as follows: First fill in the mould with the concrete, ramming and beat¬ ing it as already described until the stuff is about 1/16 inch above the mould rims, then clean off the stuff on the rims with a Avood template (rebated to fit the width of the rims), and lay the shaver flat on the rims, keep¬ ing the cutting edge outAvards, and then push it for- Avard, keeping it flat on the rims, so as to shave off the superfluous stuff. This done, sprinkle the colored ce¬ ment, with the aid of a sieve, imtil about 1/16 inch thick; then clean the rims again, and pass the shaver forAvards and backwards tAvice or thrice, which will leave a straight, smooth, and uniform-colored surface. This method effects a considerable saving in the amount of oxide and of time. The thickness of the coloring stratum is reduced mechanically to the minimum (about 1/32 inch), which is all sufficient for coloring purposes Avhere the surface is not subjected to frictional wear. As already mentioned, bullocks’ blood mixed Avith cement gives a near resemblance to red brick, but it is not a desirable material to work with, and the same effect can be obtained by the use of red oxides. Red sand, brick, and stone, all finely ground, have been em¬ ployed for coloring cement surfaces., but if too fine or in large quantities they weaken the surface; and if 452 CEMENTS AND CONCRETES coarse-grained they possess little coloring effect, be¬ cause the particles are liable to show singly, causing a spotty appearance, or the cement entirely covers the surface of each particle of sand. Powdered glass, mar¬ ble, flint, alabaster, metal filings, and mineral coloring can be effectively employed for coloring concrete sur¬ faces by mixing with the cement used for the surface coat. The surface is improved by rubbing and stoning, also polishing, after the work is dry. Other methods and quantities of colors for coloring Portland cement surfaces are given. Fixing Blocks .—Concrete fixing blocks do not shrink, warp, or rot. Consequently they are superior to wood fillets, &c. They are principally used in concrete floors, stair landings, and walls, as bearings and fixing points for wire-lathing and fibrous plaster work. Floor boards, may also be fixed to them. They are also built into brick walls for similar purposes, as well as for external wall tilings. For ceilings, stair soffits, and landings, the blocks are laid on the centrings where required, and permanently secured by laying concrete between and over them. For bearings and fixing flooring boards, they are secured flush. TYPICAL SYSTEMS OF REINFORCED CONCRETE CONSTRUCTIONS FROM VARIOUS SOURCES. Of the interesting features of modern civil engineer¬ ing, interesting because of their extreme novelty and successful application, reinforced concrete is probably most noteworthy because of its unique adaptability. How striking is the influence of steel reinforcement is best exemplified by a reference to Fig. 1. There tw') HOW TO USE THEM 453 beams are shown designed to carry ordinary floor loads, the one made entirely of concrete and the other of con¬ crete with a sheet of expanded metal imbedded in the tensile portion of the beam. The saving in mere weight of concrete alone is apparent; and when we remember that the adoption of floor beams entirely of concrete means an increase of thickness of nine inches or as¬ suming five to eight floors, an increase in the total height of the building (with extra cost and heavier walls, together with heavier foundations to carry them) of from four to six feet, we see that even as regards initial outlay for materials, the introduction of settle reinforcement into concrete construction is of import¬ ance. So far as economy in initial cost of materials is con¬ cerned, reinforced concrete is undoubtedly cheaper than either concrete or steel alone. It is not very easy to demonstrate this economy except by comparative cost in individual cases, but an approach to a systematic comparison has been made by Mr. Walter Loring Webb, as follows: A cubic foot of steel weighs 490 pounds. Assume as an average price that it can be bought and placed for 4.5 cents per pound. The steel will therefore cost $22.05 per cubic foot. On the basis that concrete may be placed for $6 per cubic yard, the concrete will cost 22 cents per cubic foot which is 1 per cent of the cost of the steel. Therefore, on this basis if it is neces¬ sary to use as reinforcement an amount of steel whose volume is in excess of 1 per cent of the additional con¬ crete which would do the same work, there is no econ¬ omy in the reinforcement, even though the reinforce¬ ment is justified on account of the other considerations. Assuming 500 pounds per square inch as the working 454 CEMENTS AND CONCRETES compressive strength of concrete, and 1G,000 as the per¬ missible stress in steel, it requires 3.125 per cent of steel to furnish the same compressive stress as concrete. On the above basis of cost, the compression is evidently obtained much more cheaply in concrete than in steel —in fact, at less than one-third of the cost. On the other hand, even if we allow 50 pounds per square inch tension in the concrete and 10,000 pounds in the steel, it requires only 0.21 per cent of steel to furnish the Fig. l.-^These Beams Are Designed to Carry the Same Load. The Upper is of Reinforced Concrete, the Lower of Plain Concrete. same strength as the concrete, which shows that, no matter what may be the variation in the comparative price, of concrete and steel, steel always furnishes ten¬ sion at a far cheaper price than concrete, on the above basis at less than one-third of the cost. The practical meaning of this is, on the one hand, that a beam com¬ posed wholly of concrete is usually inadvisable, since its low tensile strength makes it uneconomical, if not actu¬ ally impracticable, for it may be readily shown that, beyond a comparatively short span, a concrete beam will not support its own weight. On the other hand, HOW TO USE THEM 455 on account of the cheaper compressive stress furnished by concrete, an ail-steel beam is not so economical as Fig. 2.—Types of Steel Reinforcing Rods. a beam in which the concrete furnishes the compres¬ sive stress and the steel furnishes the tensile stress. Fig. 3.—A Reinforced Concrete Pier for Railway Traffic. This statement has been very frequently verified when comparing the cost of the construction of floors de- 456 CEMENTS AND CONCRETES signed by using steel I-beams supporting a fire-proof concrete floor, and that of a concrete floor having a similar floor slab but making the beams as T-beams of reinforced concrete. A good idea of reinforced concrete construction can be obtained from Fig. 3, which is an isometrical pro¬ jection of a portion of a pier strong enough to carry the heaviest railway traffic. The disposition of the steel work is shown in the piles, the main girders, and beams; and the manner in which the steel rods run¬ ning along the tensile or bottom side of the girders and beams are bent up over the top of the pile, which is here the tensile member (the beams being continu¬ ous), and then down again to the bottom of the girders and beams, is most instructive. Fig. 4.—Method of Joining Columns and Floors. The sections of the steel employed .vary in different systems, being round, flat, scpiare, angle, and tee—Fig. 2. In all cases the simplest section is the best, as it costs less, and readily allows the concrete to be rammed into the closest contact with the entire surface of the armoring. In America the Ransome system is most extensively used—a system in which a bar of twisted HOW TO USE THEM 457 steel is employed. Small sections are better than large ones, for by their use we obtain a more uniform dis¬ tribution of stress in the steel; we can also readily bend and work them into any required shape; and finally the most economical disposition of material is obtained, the metal being placed at the maximum dis¬ tance from the neutral axis. Fig. 5.—The Monier System. Expanded metal meshing (Fig. 6) is increasingly em¬ ployed, more particularly in the lighter forms of con¬ struction. It consists of sheets of metal which have been mechanically slit and expanded, so as to produce a network. This type of reinforcement has many and obvious advantages. Its mere existence is proof of good steel, and it forms an excellent key for concrete too thin to permit reinforcement in the form of rods; thus it is very useful for concrete plaster,.ceiling, and parti¬ tion wall work. A good example of reinforced con¬ crete in which expanded metal is used may be found in the Monier system (Fig. 5). An improvement on 458 CEMENTS AND CONCRETES this system is the Clinton method (Fig. 11) of using an electrically welded wire netting in combination with concrete. Clinton fabric consists of drawn wire of 6 to 10 gauge, which may be made in lengths up to 300 feet. The system is therefore a continuous bond system, which prevents the entire collapse of a span unless the weight imposed is sufficient to break all the wires. Fig. 6.—Expanded Metal. Columns and Piles .—Reinforced columns are made with either square, rectangular, or circular sections. They are reinforced with from four to twenty rods, the diameters of which vary from % to 2 V 2 inches. The rods are placed as nearly as practicable to the circum¬ ference of the column, so as to give the greatest radius of gyration for the section; but they are never placed so near the surface that they have not at least one or two inches protective covering. The steel so disposed is able to take up the tensile stresses which may be IIOW TO USE THEM 459 induced in the column by eccentric loading, lateral shock, wind pressure, and the pull of belting. Columns and piles are made in wooden boxes, each consisting of three permanent sides and a fourth side which is temporary and removable. Under the patent rights of Francois Ilennebique the reinforcing is placed Ji'ig. 7.-Ean»ome System of Erecting Colnmns. in these boxes, and adjusted by gauges to within one or two inches of the sides. The concrete is laid and rammed, about six inches at a time, with small hand rammers. The open side of the box is built up by battens fitting into grooves in the permanent sides, as the work proceeds; this enables inspection of the work 460 CEMENTS AND CONCRETES to be made, and facilitates the placing of the ties at the proper positions. The ties are made of round wire 3/16 Fig. 8.—Wood Centering and Ran some Steel Bars for 50-foot Floor Span. inch diameter and are dropped down over the top of the steel rods. They are spaced down two-ineh centres HOW TO USE THEM 461 at the bottom and top, to twelve-inch centres in the centre of length of the column, and are intended to prevent the steel rods from spreading out under the action of longitudinal loads. Fig. 4 shows the method of joining columns to the floor. Fig. 9.—Concrete Power Plant in Course of Construction. In the Itansome columns as exemplified in a recently constructed factory building (Fig. 7), the vertical re¬ inforcement consists of round rods with the connections made about 12 inches above the floor line; in order that 462 CEMENTS AND CONCRETES these rods might be continuous the ends were threaded and connected with sleeve nuts, thereby developing the full strength of the rods. Horizontal reinforcement was also used, consisting of hoops formed by a spiral Fig. 10.—Slabs of Concrete Ready for Roof. made from V± inch diameter soft wire, having a pitch or spacing of 4 inches in the basement columns, and gradually increasing to a pitch of 6 inches in the top story (Fig. 12). According to Mr. Henry Longcope the first innova¬ tion in concrete piles was the sand pile, produced by HOW TO USE THEM 463 driving a wooden form in the ground and withdrawing it, the hole being filled with moist sand well rammed. The next method adopted was to drive a metal form into the ground and after withdrawal to fill the hole with concrete. This was not successful, as it was open to the serious objec¬ tion that on withdrawing the form, the ground would col¬ lapse before the concrete could be inserted. Still another method was introduced, which consisted in dropping a cone- shaped five ton weight a num¬ ber of times from a consider¬ able height, in order to form a hole, which was afterward filled with concrete. This method never passed the ex¬ perimental stage. Coming to more successful systems we may mention a method of moulding a pile of concrete, allowing it to stand, and then driving it into the ground, a cap being used to protect the head. Of modern systems which have proven successful, Gil- breth’s pile must first be re- Fig. 11.—Clinton System Using Electrically Welded Fabric. 464 CEMENTS AND CONCRETES HOW TO USE THEM 465 corded. Gilbreth used a molded corrugated taper pile, cast with core hole the entire length of the pile, which is jetted down by a water jet and finally settled by hammer blows. Features which recommended the Gilbreth piles are the opportunities for complete inspection before driv¬ ing and the fact that they save time because they can be cased while excavation is going on. After being driven they can be loaded immediately. Naturally they present considerable skin friction. The making of these piles above the ground surface also does away with the possibility of their being damaged or squeezed out of shape by the jar occasioned by driving forms for ad¬ joining piles. Still another method is used by Raymond. Under this system piles are usually put in by either of two methods, the jetting method or the pile core method. The water jet system is used only where the material penetrated is sand, quicksand, or soft material that will dissolve and flow up inside the pile when the water is forced through the pipe, thus causing the shell to settle until it comes in contact with the next shell, and so on until the desired depth has been reached. The shells are filled with concrete simultaneously with the sinking process, and when necessary spreads are attached to keep the hole in perfect line with the pipe. The % inch pipe is left in the centre of the pile and gives it greatly increased lateral strength. If desired, the lateral strength may be further increased by inserting rods near the outer surface of the concrete. By this method, piles of any size up to two feet in diameter at the bottom and four feet at the top can be put through 466 CEMENTS AND CONCRETES any depth of water and to a suitable penetration in sand or silt (water sediment). The pile-core method is the one most generally used for foundation work and consists of a collapsible steel pile core, conical in shape, which is incased in a thin, tight-fitting metal shell. The core and shell are driven into the ground by means of a pile driver. The core is so constructed that when the desired depth has been reached it is collapsed and loses contact with the shell, so that it is easily withdrawn, leaving the shell or cas¬ ing in the ground, to act as a mold or form for the concrete. When the form is withdrawn, the shell or casing is tilled with carefully mixed Portland cement concrete, which is thoroughly tamped during the filling process. The simplex system uses another method in which the driving form consists of a strong steel tube, the lower end of which is fitted with powerful tooth jaws, which close together tightly, with a point capable of opening automatically to the full diameter of the tube while being withdrawn. The point of the form closely resembles the jaws of an alligator. At the same time the form is being withdrawn, the concrete is deposited. It is so evident that concrete is vastly superior to wood in the construction of piles that it is almost su¬ perfluous to mention the points of superiority. Con¬ crete is not subject to rot or the ravages of the teredo worm, neither can the piles constructed of concrete be destroyed by fire, and no cost is attached for repairs. While it is not possible to give accurate statistics as to the life of a wooden pile, as it varies so much under different conditions, yet Ave know that in some cases a Avooden pile is rendered Avorthless in a very feAv years, HOW TO USE THEM 467 especially when the surrounding material is composed of rotted vegetation, or where the pile is exposed by the rise and fall of tides. It is also impossible to state the exact cost of a concrete pile, as it varies also ac¬ cording to conditions. Ordinarily speaking, a concrete pile will cost from one and one-half times or two times as much as a wooden pile; but in order to illustrate where a saving can be made, the following extract is given from a report on the piles driven at the United States Xaval Academy at Annapolis, Md.: “The original plans called for 3,200 wooden piles cut off below low water with a capping of concrete. To get down to the low water level required sheet pil¬ ing, shorting and pumping, and the excavating of near¬ ly 5,000 cubic yards of earth. By substituting concrete piles, the work was reduced to driving 850 concrete piles, excavating 1,000 cubic yards of earth and placing of 1,000 cubic yards of concrete.” In the work mentioned, the first estimate for wooden piles placed the cost at $9.50 each, while the estimate for concrete piles was placed at $20 each, yet the esti¬ mate based on the use of wood piles aggregated $52,840, Avhile the estimate based on the use of concrete piles was $25,403, or a total saving in favor of concrete of over $27,000. In several instances piles have been uncovered to their full depth, and they were found to be perfectly sound in every particular. By surrounding the opera¬ tion with the safeguards provided, it is almost impos¬ sible to make a faulty pile. The concrete is made as wet as good practice will allow. Constant ramming and dropping the concrete from a considerable height tend to the assurance of a solid mass, then the target on 468 CEMENTS AND CONCRETES the ramming line or the introduction of an electric light into the form shows what is being done at the bottom of the form. Floors, Slabs and Roofs .—The system of construction for floors, slabs, and roofs is determined by the extent of the work and the nature of the loads to be carried. If intended for small buildings and offices, the items can be made before erection (Figs. 9 and 10) ; but in the case of warehouses, factories, piers, and jetties, where live loads and vibrator stresses have to be borne, a monolithic structure is secured by building in molds directly on the site. For the lighter classes of mono¬ lithic structure, expanded metal is admirably suitable; it is also much used for the roofs of reservoirs, and for thin partitioned walls. The meshing is simply laid over the ribs or floor beams, which have been already erected, and the green concrete is applied to the acquired thickness, being supported from below by suitable sup¬ porting work, which is removed as soon as the concrete has set. In cold storage factories, the floor beams and ceilings are invariably erected first, the floor being laid afterward. The ceiling is then solid with the floor beams on their under side, and the floor is solid with them on their upper side, the air space between being a great aid to the maintenance of a low temperature for refrigeration. In the Monier floors the reinforcement consists of round rods varying from % inch to % inch diameter. The rods are spaced at about six times their diameter, and are crossed at right angles, being connected by iron wire bound round them. This artificial method of securing the rods takes considerable time, and is thus a somewhat costly process. To produce continuity of HOW TO USE THEM 469 metal, the different lengths of rods are overlapped for about 8 to 16 inches, and bound with wire. The Sehluter are similar to the Monier floors, but the rods are crossed diagonally, and the longitudinal rods are of the same size as the transverse ones. The Cottancin floors have their rods interlaced like the canes of a chair seat or a basket, and the Hyatt floors have square rods with holes through which small trans¬ verse rods pass. Over fifty systems of reinforcing are in use, and in most cases the only points of difference are the shape of the section and the method of attach¬ ment and adjustment. Beams .—It is obvious that, as the span increases, a limit will soon be reached beyond which it is not eco¬ nomical to use plain floor slabs, for their dead weight becomes of such magnitude as to prohibit their use. We have thus to resort to a division of the main span by cross beams resting on columns, and the floor is laid on these beams, which are arranged to take as much of the load as to render it possible to reduce the thick¬ ness of the floor within reasonable limits. Reinforced concrete beams are typical of the construction in which the merits of two component materials are made to serve a common end; but in the particular case of steel and concrete, the actual part played by the steel is not at all well understood. Speaking generally, beams do not differ in construc¬ tional details from floors. The same reinforcement is used in both, the only difference being, that as beams are usually deeper than floors, the shearing stresses be¬ come more pronounced, the greater provision has to be made for them by a liberal use of stirrups or vertical binding rods. In some systems the reinforcement con- 470 CEMENTS AND CONCRETES sists entirely of straight rods, disposed in any part of the beam where tensile stresses are likely to be called into play. In others, specially bent rods are joined or welded to straight rods, disposed and when welding has to be done it would appear that wrought iron is more suitable than steel. It is usual to arrange the dimensions of the beams so that the whole of the compressive stresses are taken by that portion of the concrete on one side of the neu¬ tral axis; but in some cases, as with continuous beams or heavy beams of small depth, a portion of the rein¬ forcement is disturbed along compressed portion of the beam, the steel rods either taking up the excess of compressive stress over that at which the concrete can be safely worked, or else taking up the tensile stresses at the places where they occur over the supports. As a general rule we may take it that the economical depth for a reinforced concrete beam, freely supported at both ends, is one-twentieth the span, and is thus ap¬ proximately the same as that of a steel girder of equal strength. Reinforced concrete beams are now made for spans up to 100 feet for buildings, and 150 feet for bridges. But for each class of work beyond this limit, the weight becomes excessive. Several arched ribs, for much greater spans have : however, been success¬ fully built. The beams are made in much the same way as piles and columns; they can be made in sheds on the site, or in the actual position they are to occupy when fin¬ ished. The ceiling and beams are erected first, the floor being afterward worked on the top of the beams. We thus obtain a very perfect monolithic structure in which any vibration set up by machinery, falling loads, HOW TO USE THEM 471 etc., will be of much less extent than with any ordinary type of building, in which there is often a great want of rigidity, the beams and arches being loose and able to vibrate independently of other parts of the struc¬ ture. Concrete being as weak in shear as in tension, pro¬ vision is also required to take the shearing stresses. Some American designers have to this end patented special forms of reinforcement bar, in which each main tension bar has projecting upward from it ties inclined at the angle of 45 deg. (Kahn system.) These ex¬ tend to the top of the bar and take the tensile stresses arising from the shear. The corresponding compres¬ sive stress at right angles to this is carried by the con¬ crete. The system is efficient and on large spans, where weight must be reduced to a minimum, it has its ad¬ vantages. Thus, in the Ransome system (Fig. 12), the shearing stresses at the end of a beam are taken up by inclined reinforcing rods imbedded in the concrete at the junc¬ tion of beam with column. Arches .—Concrete has long had an extensive ap¬ plication in the building of arches, but until the in¬ troduction of reinforced concrete the arches that could be economically and safely constructed were limited to spans of a few feet. The general rule that the line of resistance fell within the middle third had to be ob¬ served for simple concrete arches, as for those in brick¬ work and masonry; and the thickness of the arches at the crown was thus approximately the same whether built in either of these materials. The introduction of steel reinforcement, however, made it possible not only to reduce the thickness of the ring of a given load- 472 CEMENTS AND CONCRETES Types of Reinforced Concrete Arches. HOW TO USE THEM carrying capacity, but by suitably providing for the tensile stresses to enable arches of much greater span and smaller rise to be built. Some general types of arches in reinforced concrete are shown in Figs. 13, 14, 15 and 16. Fig. 13 shows an ordinary arch with top and bottom armature. In many cases where the ten¬ sile stresses can safely be carried by the concrete the top armature can be omitted. In the Melane arches, shown in Fig. 14, the top and bottom armatures are connected by ligatures, and in the Hennebique arches (Fig. 15) stirrups are used. As a general rule, hinges should be built at the stringings and the crown, for the calculations are much simplified, and the line of re¬ sistance goes through the hinges; the arches also ad¬ just themselves better to the load and to any slow temperature changes, and when the centering is struck the arch can better take its bearings without cracking. The methods of calculations for arches are as numer¬ ous as those for beams, and generally speaking are as irrational. The Monier system is the one most gen¬ erally adopted, and over 400 bridges built on this sys¬ tem now exist in Europe. In America expanded metal and Clinton electrically-welded fabric are often used. An example of the latter construction will be found in Fig. 17. SOME MISCELLANEOUS ITEMS. % Lintels .—Concrete lintels and beams are fast super¬ seding those made of stone and wood. Lintels are generally cast and then fixed. 474 CEMENTS AND CONCRETES A Spiral Staircase built on the HenneblQue principle. HOW TO USE THEM 475 Concrete Walls .—Many ingenious plans have been introduced as substitutes for wood framing for retain¬ ing concrete while constructing walls and partitions. The most simple method is as follows: Cast a number of concrete angle slabs with an L section, and then place them level in contrary directions, thus [ spaced to the width of the proposed partition or wall until the desired length of wall is completed, and fill the openings with rough concrete. When set, place another row on this (taking care to break the joints by overlapping), and so on, until the desired height is obtained. Concrete for walls formed in situ should be deposited in layers, taking care that each layer is thor¬ oughly rammed and keyed, as described under the heading of “Ramming.” A suitable finish for ordi- ■ nary purposes, for rough walls built in situ, may be obtained by “rough trowelling.” This is done by first gauging 1 part of Portland cement, 1 part of old lime putty, and 2 parts of sand. The adding of lime renders the stuff more plastic and easy to work, with¬ out decreasing the impermeability of the work. This “limed cement” is applied with a hand-float, and is thoroughly worked into the crevices of the concrete, but leaving no body on the surface. The surface is then finished by brushing with a wet stock-brush. The walls should be well wetted before the stuff is applied. Strong Rooms .—Concrete is frequently employed in the construction of strong-rooms that are situated underground, and are rendered damp-proof as well as burglar-proof, which is useful for the storage of docu¬ ments. Concrete Coffins and Cementation .—The great im¬ provements in the manufacture of Portland cement 476 CEMENTS AND CONCRETES during the last decade has so cheapened and improved the quality as to bring it more and more to the front as one of the most useful and important materials for a variety of purposes. One of the latest uses found for it is in the construction of coffins, by the author, whose invented and registered idea was that such a coffin, made of specially prepared metallic concrete, would be impermeable, and practically indestructible, and that it would obviate the danger of spreading the poisons of disease by preventing the escape of noxious gases. The lid having a strong piece of plate glass embedded in the concrete, and directly over the face, enabled the mourners to see the features of the depart¬ ed. The edge of the open coffin had a sunk groove, and the lid a corresponding projection, only smaller, to allow for a coat of fine cement. When the joints were bedded and pressed together until the excess ce¬ ment oozed out, the coffin was hermetically sealed. The coffin should be left uncovered by cement for identification, and so that friends could view it until the time of removal to the cemetery. The face could then be covered with quick-setting cement, which, join¬ ing with the other portion of cement, would perma¬ nently embalm the body, which would further be pro¬ tected by fixing the lid in a similar way. If the prop¬ erties of this class of coffin are taken into considera¬ tion, the expense will be comparatively less than that of wood. If expense is not a special consideration, the coffin can be enriched with armorial bearings or other devices. The concrete may also be polished like real granite. One objection was raised as to the weight, but the old stone coffins and those of oak lined with lead were also heavy. Besides, the weight would bt HOW TO USE THEM 477 a protection against body-snatchers, and bearing in mind that a coffin is only moved about once in a life¬ time, or rather at death, the question of weight is un¬ important. Cementation, from a sanitary point of view, would be equal if not superior to cremation. In case of an epidemic, the coffins could be cemented at once, and stacked in the cemetery until graves or vaults were prepared for them. It may be safely said that it is a clean, safe, effectual, rapid and sanitary method of disposing of the dead. If their manufacture should not cause any great amount of extra employment for plasterers, the latter can at least make their own cof¬ fins, in frosty weather, when most works are stopped, and they could use them as baths during their life¬ time. Stonette .—Stonette is a composition of Portland ce¬ ment and fine aggregate, to imitate any kind of stone, and so made that it can be carved the same as natural stone. The Portland cement must be thoroughly air- slaked, finely sifted, and gauged with the natural ag¬ gregate in the proportion of 2 of cement to 7 of ag¬ gregate. The aggregate is composed of finely crushed natural stone, the same as that to be imitated. This should be passed through a fine sieve. It is necessary, when imitating some stones, to add a small portion of oxide to counteract the color of the cement. If a very white stone is being imitated, the addition of a small proportion of whiting or French chalk or well-slaked white limestone, is necessary to obtain the desired color. The material should be gauged stiff, and then well rammed into the mould. The carving is best done while the cast blocks are green. Tile Fixing .—Tile fixing is in some places a sepa- 478 CEMENTS AND CONCRETES rate branch of the building trade, but it is generally recruited from the ranks of plasterers, and in some districts it is done by plasterers. As regards the pro¬ cess of placing the tiles, it is best to work from the centre of the space, and if the design be intricate, to lay out a portion of the pavement according to the plan, upon a smooth floor, fitting the tiles together as they are to be laid. Lines being stretched over the foundation at right angles, the fixing may proceed, both the tiles and the foundation being previously soaked in cold water, to prevent the too rapid dry¬ ing of the cement, and to secure better adhesion. The border should be left until the last. Its position and that of the tiles are to be obtained from the drawing, or by measuring the tiles when laid loosely upon the floor. The cement for fixing should be mixed thin, in small quantities, and without sand- It is best to float the tiles to their places, so as to exclude air, and fill the spaces between them and the foundation. For fix¬ ing tiles in grate cheeks, sides and backs of fire-places, etc., equal parts of sand, plaster and hair mortar may be used. These materials are sometimes mixed with hot glue to the consistency of mortar. The tiles should be well soaked in warm water. Keen’s or other white cements are used as fixing materials for wall tiles, neat Portland cement (very often killed) being generally used for floor work. Tiles may be cut in the follow¬ ing manner: Draw a line with a pencil or sharp point where the break is desired, then placing the tile on a form board, or embedding it in sand on a flagstone, tap it moderately with a sharp chisel and a hammer along the line, up and down, or scratch it with a file. The tile may then be broken in the hand by a gentle HOW TO USE THEM 479 blow at the back. The edges, if required, may be smoothed by grinding or by rubbing with sand and water on a fiat stone. Tiles may also be sawn to any desired size. Cement should not be allowed to harden upon the surface of the tile if it can be prevented, as it is difficult to remove it after it has set. Stains or dirt adhering to tiles may be removed by wetting with diluted muriatic acid (“spirits of salts”), care being taken that the acid is all wiped off, and, after wash¬ ing, the superfluous moisture must be wiped off with a clean, dry cloth. In order to obtain a sound and straight foundation, which is imperative for good per¬ manent tile fixing, the substratum, whether on walls or floors, should be composed of Portland cement gauged with strong sand or similar aggregate in proportion of 1 of the former to 3 of the latter. The surface must be ruled fair and left rough, so as to form a fair bed and key for the fixing materials and tiles. Setting Floor and Wall Tile .—As this work properly belongs to the plasterer, where no regular tile setter is available, I have thought it proper to publish the fol¬ lowing instructions for doing this work, which are taken from a treatise prepared for the Tile Manufac¬ turers of the United States. This treatise, in pamphlet form, was intended for distribution among buyers and workers in tiles, and the directions and suggestions laid down in it are of the best, and quite suited to the wants of the wmrkingmen: Foundations .—A good foundation is always neces¬ sary, and should be both solid and perfectly level. Tile should always be laid upon concrete foundation, pre¬ pared from the best quality of Portland cement and clean, sharp sand and gravel, or other hard material. 480 CEMENTS AND CONCRETES (Cinders should never be used, as they have a tendency to destroy the life of the cement and cause it to dis¬ integrate.) A foundation, however, may also be formed of brick or hollow tile embedded solidly in and covered with cement mortar. Concrete should be allowed to thoroughly harden before laying the floor, and should be well soaked with water before laying the tile. Lime mortar should never be mixed with concreting. Concrete should consist of one part Portland cement, two parts clean sharp sand, two parts clean gravel, and thoroughly mixed with sufficient water to form a hard, solid mass when well beaten down into a bed, which should be from 2*4 inches to 3 inches thick. If the concrete bed can be made over three inches in thickness, the concrete can then be made of one part Louisville cement, one part clean sharp sand, one part clean gravel and thoroughly mixed with sufficient wa¬ ter, as above described. For Floors. —The surface of the concrete must be level and finished to within one (1) inch of the fin¬ ished floor line, when tile y> inch thick i^ used, which will leave a space of *4 inch for cement mortar, com¬ posed of equal parte of the very best quality Portland cement and clean sharp sand. The distance below the surface of the finished floor line, however, should be governed by the thickness of the tile. For Wood Floors. —When tiles are to be laid on wood flooring in new buildings the joists should be set dve inches below the intended finished floor line and spaced about 12 inches apart and thoroughly bridged, so as' to make a stiff floor, and covered with one-inch boards not over six inches wide (boards three inches wide preferred), and thoroughly nailed, and the joints y 8 HOW TO USE THEM 481 inch apart to allow for swelling. (See No. 31.) (A layer of heavy tar paper on top of wood flooring will protect the boards from the moisture of the concrete, and will also prevent any moisture from dripping through to a ceiling below.) In Old Buildings .—Cleats are nailed to joists five inches below the intended finished floor line, and short pieces of boards % inch apart fitted in between the FLOOR Llrtt Tnrrmrp. -rue “•CfMf/v r -covc/icre -Sl/B FLOOR CLEATS -BRIDGING OUT % QCirD'&vfi' lllljllllil X - J 0 Fig. 32. joists upon the cleats and well nailed, and the joists thoroughly bridged. The corners on the upper edge of the joists should be chamfered off to a sharp point (see Fig. 32), as the flat surface of the joists will give an uneven foundation. When the strength of the joists will permit, it is best to cut an inch or more off 482 CEMENTS AND CONCRETES the top. (Where joists are too weak, strengthen by thoroughly nailing cleats six inches wide full length of joists.) When the solid "wood foundation is thus prepared, concrete is placed upon it as above directed. Where Steel Beams and hollow tile arches are used, frequently very little space is left for preparing a proper foundation for setting tile, as the rough coating is usually put in by the hollow tile contractor to pro¬ tect his work, but this covering should always conform '>ipp! rfxr die noato/E cavcKcrt -ARCH Fig. 33. to the requirements for a solid tile foundation. Should this not be the case, the tile contractor should remove sufficient of the covering to allow him to put down a foundation that will insure a satisfactory tile floor. (Cinders, lime, mortar or inferior material must never be used.) The tops of iron beams should be from three to four inches below ihe finished floor line, to prevent floors, when finished, showing lines of the beams. For Hearths. —The foundation for hearths should be placed upon a brick arch, if possible, to ensure perfect fire protection, and then covered with concrete in the same manner as directed for tile floors. If placed upon a sub-foundation of wood, the concreting should be at least six inches thick. (See Figs. 34 and 35.) HOW TO USE THEM 483 not . /w>//?r/7rrrr77Tr t 7 Fig. 35. T 484 CEMENTS AND CONCRETES For Walls .—When tiles are to be laid on old brick walls the plaster must be all removed and the mortar raked out of the joints of the brick work to form a key for the cement. On new brick walls the points should not be pointed. When tiles are to be placed on stud¬ ding, the studding should be well braced by filling in between the studding with brick set in mortar to the height of tile work (see Fig. 36) ; or brick work may be omitted and extra studding put in and thoroughly Fig. 36. bridged, so as to have as little spring as possible, and this studding then covered with sheet metal lathing. (See Fig. 37.) (Tile must never be placed on wood lath or on old plaster.) The brick walls must be well wet v ith water and then covered with a rough coating' of cement mortar, composed of one part Portland ce- HOW TO USE THEM 485 ment and two parts clean sharp sand. When tiles are placed on metal lathing, hair should be mixed with the cement mortar to make it adhere more closely to the lath. The cement mortar should be y 2 inch thick, or sufficient to make an even and true surface to within one (1) inch of the intended finished surface of the tile, when tile y 2 inch thick is used, which will allow a-space of y 2 inch for the cement mortar, composed as above for rough coating the walls. The face of the cement foundation should be roughly scratched and allowed to harden for at least one day before com¬ mencing to lay the tile. If any lime is mixed with the cement mortar for setting the tiles, it should never exceed 10 per cent., and great care must be used to have the lime well slaked, and made free from all 486 CEMENTS AND CONCRETES lumps by running through a coarse sieve, in order to guard against “heaving” or “swelling,” and thus loosening or “lifting” the tiles. Important .—The foundation for both floor and wall tiling should be thoroughly brushed, to remove all dust and small particles adhering to it, and then well wet before putting on the cement mortar. To ensure a perfect bond it is best to coat the foundation by brush¬ ing over it pure cement mixed in water. Cement .—The very best quality of Portland cement should always be used for setting either floor or wall tile and for grouting the floors, and the very best quality of Keene’s Imported Cement for filling the joints in the wall tiling. Sand. —Clean, sharp grit sand, free from all salt, loam or other matter, and perfectly screened before mixing with the cement, should always be used. Mortar .—For floors or vitreous tiles, should be com¬ posed of equal parts of cement and sand, and for wall tiles one (1) part of cement and two (2) parts sand. The mortar should not be too wet, but should be rather stiff, and should always be used fresh, as mortar, when allowed to set before using, loses a portion of its strength. Soaking .—Tiles must always be thoroughly soaked in water before setting, which makes the cement unite to the tiles. The Tiles for the Floors are first laid out to ascer¬ tain if they are all right and compared with the plan provided for laying the floors. Strips are then set, beginning at one end of and in the centre of the room, and level with the intended finished floor line. Two sets of guide strips running parallel about 18 to 30 HOW TO USE THEM 487 inches apart should be set first. (See Fig. 38.) The mortar is then spread between them for about six to ten feet at a time, and level with a screed notched at each end, to allow for the thickness of the tiles. The tiles are placed upon the mortar, which must be stiff enough to prevent the mortar from working up be- Fig. 38. tween the joints. The tiles are to be firmly pressed into the mortar and tamped down with a block and hammer until they are exactly level with the strips. When the space between the strips is completed, the strips on one side of the tile is moved out 18 to 30 inches and placed in proper position for laying an¬ other section of tile, using the tiles which have been 488 CEMENTS AND CONCRETES laid for one end of the screed, and the laying of the tile continued in the same manner until the floor is finished. When the cement is sufficiently set, which should be in about two days, the floor should be well scrubbed with clean water and a broom, and the joints thoroughly grouted with pure cement (mixed with water to the consistency of cream). As soon as this begins to stiffen, it must be carefully rubbed off with sawdust or fine shavings and the floor left perfectly clean. Ceramics .—The foundation and cement mortar for ceramics are the same as for plain or vitreous floors, and the guide strips used in the same manner. The cement mortar is then spread evenly and the tile sheets laid carefully on it with the paper side up. After the batch is covered, the tile setter should commence to press the tile into the mortar, gently at first, firmly afterwards, using block and hammer, thus leveling the tile as correctly as possible. The tile should be beaten down until the mortar is visible in the joints through the paper; however, without breaking it. The paper is then moistened, and after it is well soaked and can be easily removed, it is pulled off backwards, starting from a corner. After removing the paper, the tile should be sprinkled with white sand before fin¬ ishing the beating, so that the tiles will not adhere to the beater, owing to the paste which is used in mount¬ ing them. Corrections of the surface are then made by leveling it with block and hammer. The filling of the joints and cleaning of the surface is a delicate op¬ eration, as the looks of this work depends largely upon it. The joints are to be filled with clean Portland cement mixed with water. This mixture is forced into HOW TO USE THEM 489 the joints with a flat trowel (not with a broom, which often scrapes out the joints). After the joints are Fig. 39. filled, the surplus cement is removed from the sur¬ face by drawing a wet piece of canton flannel over it. This piece of cloth must be washed out frequently with clean water. After the floor is cleaned, it should be 490 CEMENTS AND CONCRETES allowed to stand for a day or two, when the whole floor is to be rubbed with sharp sand and a board of soft lumber. This treatment, which the last traces of cement, is. preferable to the washing off with an acid solution, as it will not attack the cement in the joints. In laying the tile sheets on the cement, care should be taken to have the widths of joints spaced the same as the tile on the sheets to prevent the floor having a block appearance. The Tiles for the Walls or Wainscoting are first laid out and compared with the plan provided .for setting them. Guide strips are then placed on the wall paral¬ lel and about two feet apart, the bottom one being so HOW TO USE THEM 491 arranged as to allow the base to be set after the body is in place. (See Fig. 40.) When a cove base is used it may be necessary to set it first, but in all cases must be well supported on the concrete. (See Fig. 41.) The strips must be placed plumb and even with the intend¬ ed finished wall line. The method of setting wall tile is governed to some extent by the conditions of the wall on which they are to be set, and must be decided by the mechanic at the time, which process he wilL use, whether buttering or floating, as equally good work can be done by either, by following the instruc¬ tions, as stated below. Floating Wall Tile .—The mortar is spread between the guide strips for about five feet at a time and lev¬ elled with a screed notched at each end to allow for the thickness of the tile. (See Fig. 39.) The tiles are placed in position and tamped until they are firmly united to the cement and level with the strips. When the space between the strips is completed, which should be one side of the room, the strips are removed and the work continued in the same manner until com¬ pleted. When the tiles are all set, the joints must be carefully washed out and neatly filled with thinly mixed pure Keene’s Cement, and all cement remaining on the tile carefully wiped off. Buttering Wall Tiles .t—The cement mortar is spread on the back of each tile, and the tile placed on the wall, and tapped gently until firmly united to the wall and plumb with the guide strips. When the tiles are all set, the joints must be carefully washed out and filled with Keene’s Cement, and the tiles cleaned as directed above. When fixtures of any kind are to be placed on the 492 CEMENTS AND CONCRETES tile work, such as plumbing in bathroom, provision should be made for them by fastening wood strips on the wall before the rough or first coating of cement mortar is put on, the strips to be the same thickness as the rough coating. The tiles can be placed over the strips by covering them with cement mortar, and when thoroughly set, holes can be bored in the tiles for fastening the fixtures without injuring the tiling. Hearth and Facing Tile are set in the same manner as for floors and walls. Cleaning .—It is absolutely necessary to remove with sawdust, and afterwards with a flannel cloth and wa¬ ter, all traces of cement which may have been left on the surface of the tile, as it is hard to remove after it is set. After thoroughly cleaning the floor, it should be covered with sawdust and boards placed on the floor for several days where there is walking upon it. A white scum sometimes appears on the surface of the tile, caused by the cement. This can generally be removed by washing frequently with plenty of soap and water. If this does not remove it, then use a weak solution of 15 parts muriatic acid and 85 parts wa¬ ter, which should only be allowed to remain on the tile for a few minutes, and then thoroughly washed off. Cutting of Tile .—When it is found necessary to cut tile the following directions are given: Tools.n —The chisels used should be made of the best tool steel, and should always be sharp. They should be of small size, the edge not being wider than one- fourth inch. The hammer should be light, weighing about six ounces, having a slender handle. After the HOW TO USE THEM 493 exact shape of the tile has been determined, lines should be drawn on the surface of the tile with a lead pencil, giving the exact direction of the cut desired. This line should be followed with the chisel, which is held at right angles with the surface, the hammer giving the chisel sharp, decisive raps. After the line has been repeatedly traversed with the chisel, a few sharp blows against the back of the tile opposite the mark on the face will break it at the place thus marked. To cut glazed or enamel tiles, they should be scratched on the surface with a tool at the place where it is desired to break them, and then gently tapped on the back opposite the scratch. Caution should be used not to allow any one to walk upon or carry anything heavy over the floor, or have any pounding about wall work for several days, or until the tiles are firmly set. Unless these precau¬ tions are taken it will be impossible to guarantee a first-class job. Tile work is freqit-^ly condemned when the fault lies with the rush of other contractors to finish their work. Laying Tile on Wood .—A new material called “Monolith.” manufactured by The Wisconsin Mantel & Tile Co., that enables the workman to lay tiles on a wooden floor. There are many places where tile could be used, but on account of the added weight to the floor by the use of cement, concrete foundation, it is impracticable to lay in many places, but by the use of Monolith, the only weight that is added is the tile itself and the Monolith bed it is laid in. Both ma¬ terials are only five-eighths of an inch in thickness when laid. 494 CEMENTS AND CONCRETES Fig. 42. HOW TO USE THEM 495 The illustration, Fig. 42, shows the method of laying the tile. The paper to which the small pieces of tiles are glued is seen on top of tiles. The dark part shows the patent cement, or Monolith. I show herewith, at Nos. 43 and 44, twelve designs for decorative borders of various kinds, and in 45 and 46 I show two designs well suited for vestibules, store entrances or for hearths in fire-places. Good Concrete .—In determining the proportions of the aggregates and cement for a certain piece of work, it is necessary usually to take samples of the broken stone (or gravel) and sand which are most available to the site and make measurements of the percentage of voids in the stone which must be filled by the sand and the percentage of voids in the sand which must be filled by the cement. This is done by taking a cubic foot box and filling it with broken stone in a thoroughly wet state. The box is then filled with as much water as is required to completely fill it, in addi¬ tion to the stone, which upon bein^t^ured off gives the relation between the volume of the voids and the volume of the stone. The required amount of local sand thus determined is then measured out and placed in the box with the stone in a damp state. Water is then used to determine the percentage of voids left in the sand, which gives the approximate amount of cement required, although an excess of cement is al¬ most invariably used. Engineers everywhere differ regarding the best proportion to be used, but in gen¬ eral the above test, roughly made, will determine it well enough. The proportions which are most univer¬ sally used are as follows: 1 cement, 2 sand, 4 broken stone; where extremely strong work is desired. Tests 496 CEMENTS AND CONCRETES Border No. 411 Border No. 412 Border No. 413 Border No 414 Border No. 415 Border No. 416 Decorative Borders in Round, Square and One Inch Hexagons of Various Colors. Fig. 43. HOW TO USE THEM 497 ■ V. ‘. - Border 146. 543 Wide. ?- i:'. Wide, Border No. 545 ■ 11" Wide 13" Wide. 16” Wide. IHHIlft iciruiMiiitUiuS lUinuinninaiDHiiuiii. A Series of Borders in Square Tiles, Each in a Variety of Colors. Fig. 44. CEMENTS AND CONCRETES 498 show that a 6-incli thickness of 1-2-4 concrete properly made is waterproof np to about 50 pounds to the square inch. This concrete is frequently used for facing dams. 1-3-6 is the proportion generally used for the interior of dams and large structures. It is entirely suitable for large foundations. 1-4-8 is frequently used for foundation work, and when properly mixed Fig. 45. makes good concrete, although it is about the limit of what is considered good work, and would not be suitable for very important structures. 1-5-10 is equal to any concrete made with natural cement. It is a well-known fact that the volume of concrete when mixed with water is somewhat less than the volume of the aggregate and cement before mixing. The con¬ tractors’ rule is that the volume of mixed concrete is HOW TO USE THEM 499 Fig. 46. the concrete was in the form and tamped, it would show moisture on the surface. The tamping is a very important part of the operation, and the quality of the work is dependent upon how well this is super¬ intended, as unless it is well and thoroughly done the concrete is liable to be honeycombed and imperfect, especially near the forms. With the growth of the equal to the volume of the stone plus one-half to one- third the volume of sand. There has been much discussion among engineers and others as to the amount of water that should be added to the aggregates and cement for making the best concrete, and while it is not the purpose of this paper to enter into this controversy, it might be said that the modern tendency is toward wet concrete. The old way was to add just enough water so that when all 500 CEMENTS AND CONCRETES use of concrete the old method of putting it in the forms nearly dry and depending on tamping to con¬ solidate it has been more or less abandoned, and the more modern way is to put the concrete in quite wet, as less tamping is required and much labor and ex¬ pense saved. One of the great objections to this scheme is that if care is not taken the water will tend to wash the cement from the stone and sand; in other words, unmix it. However, it may be said that it is now generally understood that rather wet concrete properly handled makes better work. The amount of water to be added to the aggregates and cement va¬ ries from 1 water to 3 cement by measurement to 12 per cent of water by weight. Mr. Carey, of New- haven, England, says that 23 gallons water per cubic yard of cement was the best mixture. Quite frequent- t ly salt water is used in mixing concrete in cold weather to prevent freezing, and it seems to have no ill effects on the resulting mixture. Reinforced Concrete .—Up to the last few years the use of concrete as a building material was chiefly con¬ fined to the construction of foundations, piers, reser¬ voir dams and similar purposes, in which the stresses to be met were almost entirely simple pressures. In¬ deed, even fifteen years ago, many engineers looked askance on the use of concrete for arches, considering it for this purpose much inferior to brick. Much of the caution shown in extending the use of this valua¬ ble material doubtless arose from the frequency with which concrete masonry exhibited unsightly cracks, due largely to the material being allowed to get too dry while hardening. At the same time, careful ex¬ amination has shown that cracks of the same char- HOW TO USE THEM 501 acter are common in masonry of all kinds, but are unnoticed, because they follow the regular joints of the structure; whereas, on the smooth uniform sur¬ face of the concrete, cracks of much less significance are immediately visible. The plan of reinforcing the material with metal, of which several systems have been introduced during the last four years, has greatly extended the possible use of concrete; and it appears that in many cases a reinforced concrete bridge may compete, even in first cost, with a steel girder; while as regards upkeep, it has, of course, many advantages. Small bridge cul¬ verts of this material were extensively used by Rus¬ sian engineers in building the Manchurian Railway. For openings of some 7-foot span, flat slabs of con¬ crete reinforced with rails were used, the thickness being 8% inches. A similar system was used for spans up to 21 feet, the concrete, however, being thickened at the center as the span increased, the depth at this point being 2 feet 614 inches for the 21-foot span, and proportionately less for smaller openings. The thick¬ ness at the bearings was, however, the same in all cases, viz., 8 % inches. The line was thrown over the spans as little as seven days after completion. The concrete consisted of one part cement, two sand and five broken stone. The system in this case had great advantages, as stone for masonry was unobtainable, and could, moreover, only be used for arches, which would have necessitated the use of higher embank¬ ments than were required with the ferro-concrete, used as described. Much larger spans have, of course, been built than those mentioned. One, of 153-foot span, carrying four main line tracks, has recently been 502 CEMENTS AND CONCRETES built for the Lake Shore and Michigan Southern Rail¬ road, while Mr. Edwin Thacker, M. Am. Soc. C. E., states he considers the system feasible for spans up to 500 feet, and has actually got out designs for a span 300 feet, the cost comparing favorably with that of a steel bridge. One great drawback to the extension of the system lies in the difficulty in proportioning structures thus built in a thoroughly rational manner. In the case of steel bridges certain simple assumptions as to the elasticity and strength of the material suffice. These assumptions are doubtless not absolutely exact, but are sufficiently near the truth for practical purposes. The elastic properties of concrete are, however, very dif¬ ferent from those of steel; Hooke’s law is not even ap¬ proximately correct, and, moreover, the material al¬ ways takes a permanent set when first loaded. The true distribution of the stress and strain on a concrete beam is thus a much more complicated matter than it is in the case of a steel joist, in which it is permissible, within working limits of stress, to assume the accuracy of Hooke’s law. The assumption generally made in the case of ferro-concrete is that plane sections of a concrete beam remain plane after bending. This pos¬ tulate is, of course, that commonly made in propor¬ tioning steel work; and in the latter case, stress being proportional to strain, the usual formula for the work¬ ing strength of beams is readily reduced. In the case of concrete, however, the stress-strain curve is much more complex. Nevertheless, M. Considere has shown that by making experiments on concrete in Simple ten¬ sion and compression, and plotting the corresponding stress-strain curves, it is possible to deduce from these HOW TO USE THEM 503 with fair accuracy the load-cleflection curve of a ferro¬ concrete beam. This method, though logical, leads, however, to no simple formula for the strength; and in applying this method the working load of any particular concrete beam would have to be deduced by the tedious proc¬ ess of scaling off the stress-strain curves at a num¬ ber of points, and combining the results. A further question arises as to whether this stress-strain curve should be the initial stress-strain of the concrete, or that obtained after repeated loadings. Probably the latter is the best to choose, but in that case it by no means follows that the metal reinforcement is free from initial stresses when the load is applied to the beam; and if the metal is subject to initial stress, it is obvious that similar ones must exist in the concrete. In fact, M. Considere has shown that this is necessarily the case in any circumstances, since, if the concrete is allowed to harden under water, it tends to expand, and this expansion is resisted by the metal reinforce¬ ment. If, on the other hand, the hardening takes place in air the concrete tends to contract; and this contraction being again resisted by the metal, a series of fine hair cracks are produced which, visible at low loads, are readily detected on the tension side of a heavily loaded ferro-concrete beam. Tn view of the uncertainties introduced by the dif¬ ferent factors above mentioned, it is really questionable whether, after all, the theoretically objectionable for¬ mula of M. Hennebique is not as good as any other. The latter all involve a preliminary calculation of the position of the neutral axis, which varies with the per¬ centage of metal used, and with the type of stress- 504 CEMENTS AND CONCRETES strain curve assumed for the concrete; and also with the maximum stress at any particular section. Thus, in a centrally-loaded beam, its position at the ends is entirely different from what it is at the centre. M. Hennebique, on the other hand, makes no attempt to locate this neutral axis, and simply assumes that one- half of his beam resists compression, and that the stress is uniformly distributed over this half. The moment of this compression about the centre of the section equates to half the moment due to the load, and the other half of the moment due to the load he equates to the moment about the centre of the section of the tensile stress on the metal reinforcement. The working strength of concrete in compression, he takes as 350 pounds per square inch, and neglects entirely its strength in tension. The working tensile stress on the steel reinforcement he takes as 14,000 pounds per square inch. This method is, of course, totally illogi¬ cal, yet many thousand cubic yards of ferro-concrete have been successfully designed on these lines; and a comparison of the strength of ferro-concrete beams as calculated by this formula, and by those of a more rational type, shows very little difference between the two for a considerable range of metal to concrete. On the other hand, it must not be forgotten that formulae which are non-rational in form are always risky when applied to extreme conditions. Concrete being as weak in shear as in tension, pro¬ vision is also required to take the shearing stresses. Some American designers have to this end patented special forms of reinforcement bar, in which each main tension bar has projecting upward from the ties in¬ clined at an angle of 45 degrees. These extend to the HOW TO USE THEM 505 top of the bar and take the tensile stresses arising from the shear. The corresponding compressive stress at right angles to this is carried by the concrete. The system is doubtless efficient, and on large spans, where weight must be reduced to a minimum it may have some advantage; but in work of ordinary proportions it seems to be little superior to the Hennebique sys¬ tem, in which the necessary strengthening is provid¬ ed by stirrups of flat iron bent into a U shape. The main reinforcing bars rest in these stirrups at the lower ends. The spacing of the stirrups depends upon the “web stresses” to be taken, which can easily be calculated by assuming the reinforced beam to be a latticed girder, the lower chord of which is represented by the metal reinforcement, the upper one by the centre of the compression half of the beam, while the stirrups represent vertical ties, which may be taken as con¬ nected together at top and bottom by inclined imag¬ inary struts. The advantage of this simple method of reinforcing for shear lies in the possibility of using common rolled sections for the whole of the rein¬ forcement. M. Hennebique constructs most of his ferro-concrete work on the monolithic system, girders, piers, columns and floors being solidly connected together. It is, therefore, necessary to provide for the reversed bend¬ ing moments over the point of support, which is done by bending up half of the total reinforcement bars, so that the ends of the span are close to the upper surface of the beam, and thus in a position to take the heavy tensile stresses which ensue at these points when the monolithic system of construction is fol¬ lowed. The exact calculation of the reactions and 506 CEMENTS AND CONCRETES bending moments here is impracticable, if not actually impossible; and those engineers who attach much im¬ portance to having all structures statically determinate will doubtless object to the plan, but experience shows that the advantages gained are very considerable. The structure then resists as a unit, and in particular its rigidity is marvelous. Some comparative tests on this point, made by the Railway Company, showed that with a ferro-concrete floor subjected to blows four times as heavy as were applied to an equivalent floor constructed of brick arches on steel joists, the deflection was only one- seventh as great. The extreme rigidity attainable with the monolithic system of construction was also very evident in the case of the large ITennebique bridge at Purfleet. Since a structure fails by strain rather than by stress, the small deformation noted with ferro-concrete are evi¬ dent that as an average the material is relatively lit¬ tle tried by the loads carried. It must, however, be admitted that this low average strain is quite com¬ patible with extremely severe strain at particular points; but it is, of course, the business of the designer, by suitably disposing his material to avoid these pos¬ sible local abnormalities. Occasionally, doubts have been expressed as to whether the metallic reinforcement may not suffer from corrosion as time goes on. This would be extremely dangerous if it occurred, since the metal being out of sight, its loss of strength might remain undetected un¬ til, some day, the structure might fall under its ordi¬ nary working load. Fortunately, much evidence is available to the effect that steel or iron thoroughly HOW TO USE THEM 507 imbedded in concrete is permanently protected from rust. Americans, indeed, are so positive on this point that they have recently constructed a number of reser¬ voir dams in ferro-concrete. In some cases these have been arched, but in others they have been straight. The cross-section in the latter case is generally a hollow triangle, the sides of which are connected together by diaphragm walls from point to point. The dam is also anchored to its site, though generally the weight pro¬ vided is sufficient to make the structure safe against overturning, quite apart from the help received from the anchor-bars. Progress in the use of reinforced concrete has been somewhat slow in England. The railway engineers, in view of their enormous responsibilities, have not un¬ naturally hesitated to adopt a material in which it was impossible to calculate the strength with accuracy, and of which experience as to its reliability was very re¬ cent. In the larger cities, moreover, its use has, quite apart from this, been restricted by the inelastic na¬ ture of the building regulations, which have been reached upon the assumption that finality had been reached in the matter of building construction. Hence, permission to erect warehouses and factories in ferro¬ concrete has always been difficult—and often impossi¬ ble—to obtain, though experience has shown that the new material is most excellent as a fire-resister. At the great Baltimore fire it was found that the concrete exposed to the flames was seldom damaged to a greater depth than one-half inch, though projecting corners suffered somewhat more, being rounded off by the flames to a radius of about two inches, pointing to the advisability of constructing the concrete with well* 508 CEMENTS AND CONCRETES rounded corners in the first instance. The only rea¬ sonable grounds of objection to any proposed system of building construction are its dangers from a struc¬ tural sanitary or fire-risk point of view. As a result of much investigation and experiment, the following conclusions were arrived at for the guidance of the designer and constructor of reinforced concrete: 1. What drawings and details should be prepared before work is commenced. 2. The nature of the materials which may be em¬ ployed and the standards to which these should com¬ ply, i. e., (a) the metal in reinforcement, (b) the matrix, (c) the sand, (d) the gravel, stone, clinker or other aggregate, (e) water. 3. What are the proportions for concrete to be used in different cases. 4. How the ingredients for concrete are to be mixed and deposited on the work. 5. The distances to be allowed between the reinfor¬ cing bars and what covering of concrete is necessary. 6. What precautions are necessaiy in the design and erection of centring and false work, and liow long the whole or portion of centring and false work should re¬ main in position. 7. The rules which should be used in determining the dimensions of the several parts necessary for secur¬ ity, and what safe stresses should be allowed. 8. The supervision necessary and the special matters to which it should be directed. HOW TO USE THEM 509 9. The fire-resisting properties of reinforced con¬ crete. 10. Its adaptability for structures where resistance to liquid pressure is essential, and what special precau¬ tions may be advisable under these conditions. 11. • What are the necessary conditions for its perma¬ nence; resistance to rusting of metal, disintegration of concrete or effects of vibration. 12. The testing of the materials employed and of the finished structures. 13. What provisions are desirable in Building Laws or Government regulations relating to buildings and other structures so far as these affect the use of rein¬ forced concrete. INDEX PAGB MATERIALS: Limes . 27 Cements . 30 Mortars . 28 Sand . 28 Plasters and laths. 31 WORKMANSHIP: External work . 35 Internal work . 37 SPECIFICATION CLAUSES: Materials . 42 Workmanship . 43 PREPARATION OF BILL OF QUANTITIES: Materials . 46 Workmanship . 46 Laths . 48 TOOLS AND APPLIANCES: Hoes and drags. 50 The hawk . 52 The mortar board. 52 Trowels . 52 Floats . 52 Moulds . 54 The pointer. 54 The paddle . 55 Stopping and picking out tools. 55 Mitering rod. 55 Scratcher. 55 511 512 INDEX PAGE TOOLS AND APPLIANCES.—Continued. Hod . 55 Sieve. 56 Sand screens . 56 Mortar beds . 57 Slack box. 57 Lathing . 57 Lather’s hatchet. 58 Nail pocket . 58 Cut-off saw. 58 PLASTER. LIME, CEMENTS, SAND, ETC.: Plaster of Paris. 60 Quick and slow setting plaster. 62 Testing . 63 French plaster. 65 Limes . 65 Hydraulic limes . 66 Calcination. 69 Slaking . 70 Mortar . 73 Hardening of mortar. 78 Magnesia in mortars. 82 Effects of salt and frost in mortar. 84 Sugar with cement. 86 Sugar in mortar. 88 Lime putty . 89 Setting stuff. 90 Haired putty setting. 91 Lime water . 91 Hair . 91 Fibrous substitutes for hair. 92 Sawdust as a substitute for hair. 93 Sand . 94 Mastic . 96 Scotch mastic . 96 Common mastic . 97 Mastic manipulation . 97 INDEX 513 PAGE PLASTER, LIME, CEMENT, ETC.—Continued. Hamelein’s mastic . 97 Mastic cement .■. 98 TERMS AND PROCESSES: Three-coat work. 99 First coating. 99 Scratching . . v . 100 Rendering . 102 Screeds. 103 Floating. 103 Flanking . 106 Scouring coarse stuff. Ill Keying . 112 Setting . 114 Laying setting stuff. 115 Scouring setting stuff. 115 Troweling and brushing setting stuff. 116 General remarks on setting. 117 Common setting . 119 Skimming . 119 Colored setting. 119 Gauged setting. 120 Gauged putty set. 120 Putty set. 121 Internal angles .,. 121 External angles . 121 Skirtings . 122 Two coat work. 123 One-and-a-half coat work. 123 Stucco . 124 Old stucco. 124 Common stucco . 129 Rough stucco . 129 Bastard stucco . 130 Troweled stucco . 130 Colored stucco. 131 Method of working cements. 131 514 INDEX PAGE TERMS AND PROCESSES.—Continued. White cement efflorescence. 138 Cornice brackets. 139 Cornices. 140 Mitring. 155 Mitre mould . 156 Fixing enrichments . 159 Mitring enrichments . 160 Pugging . 163 Sound ceilings . 164 Cracked plaster work. 165 Repairing old plaster.1 .. . . 165 Gauged work. 168 Joist lines on ceilings. 169 Rough casting . 170 VARIOUS METHODS OF RUNNING COR¬ NICES, CIRCLES, ELLIPSES AND OTHER ORNAMENTAL STUCCO WORK: Diminished columns .'. 177 Column trammel .'. 180 Constructing plain diminished columns. 183 To set out the flutes of diminished columns.... 183 Constructing diminished fluted columns.. 185 Forming diminished fluted column by the rim method . 193 Running diminished fluted column by the Col¬ lar method . 196 Diminished fluted pilasters. 200 Pannelled coves . 200 Diminished mouldings. 204 False screed method. 204 Running double diminished mouldings. 208 Diminished rule method. 208 Top rule method. 211 Cupola panels and mouldings. 215 Panelled beams. 220 INDEX 515 PAGE VARIOUS METHODS, ETC.—Continued. Trammels for elliptical mouldings. 220 Templates for elliptical mouldings. 224 Plasterer’s oval . 228 Coved ceilings. 233 Circle mouldings on circular surfaces. 233 Forming niches . 235 Running an elliptical moulding in situ. 240 MISCELLANEOUS MATTERS: Depeter . 243 Sgraffitto . 243 Fresco . 251 Fresco secco . 255 Indian fresco and marble plaster. 256 Scagliolia . 260 Artificial marbles. 262 Pick’s neoplaster .. 263 Scagliolia manufacture . 264 Mixing . 270 Colors and quantities. 272 Polishing white scagliolia. 275 Polishing scagliolia . 276 Marezzo . 277 Granite finish .'.. 282 Granite plastering . 283 CEMENTS AND CONCRETES AND HOW TO USE THEM: Fine concrete.. 291 Matrix . 293 Aggregate . 294 Porous aggregates . 295 Compound aggregates. 296 Sand and cement. 297 Fire-proof aggregates . 300 Voids in aggregates. 302 Crushing strength of concrete.302 516 INDEX PAGE CEMENTS AND CONCRETES.—Continued. Water for concrete. 303 Gauging concrete. 305 Ramming concrete. 308 Thickness of concrete paving. 309 Concrete paving. 310 Eureka paving . 312 Eureka aggregate. 313 Eureka quantities . 314 Levels and falls.'. 315 Pavement foundations. 316 Screeds and sections. 318 Laying concrete pavements. 320 Troweling concrete . 321 Grouting . 322 Dusting. 322 Temperature . 322 Non-slippery pavements . 323 Grooves and roughened surfaces. 323 Stamped concrete . 325 Expansion joints . 325 Washing yards .328 Stable pavements. 328 Concrete slab moulds. 329 Slab making . 330 Induration concrete slabs. 330 Mosaic . 331 Concrete mosaic. 333 Concrete mosaic laid in situ. 334 Storing cement . 337 Cement mortar. 337 Mixing . 338 Grout . v . 339 Lime and cement mortar. 339 Cement mortar for plastering. 339 Materials for making concrete sand. 340 Gravel . 341 INDEX 517 PAGE CEMENTS AND CONCRETES.—Continued. Crushed stone. 341 Stone versus gravel. 342 Cinders . 342 Concrete . 343 ' Proportioning materials . 344 Aggregate containing fine material. 345 Mechanical mixers . 346 Mixing by hand. 346 Consistency of concrete. 347 Use of quick setting cement. 347 Coloring cement work. 347 Depositing concrete. 348 Retempering . 349 Concrete exposed to sea-water. 349 Concrete work in freezing weather. 350 Rubble concrete. 350 To face concrete. 351 Wood for forms. 352 Concrete sidewalks . 352 Excavation and preparation of subgrade. 353 The subfoundation. 353 The foundation . 353 The top dressing or wearing surface. 354 Details of construction. 384 Concrete basement floors. 358 Concrete stable floors and driveways. 358 Concrete steps . 359 Reinforced concrete fence posts. 360 Reinforcement . 362 Concrete for fence posts. 362 Molds for fence posts. 363 Attaching fence wire to posts. 365 Molding and curing posts. 365 Concrete building blocks. 368 Tests of concrete fence posts. 370 Retempering . 378 518 INDEX PAGE CEMENTS AND CONCRETES.—Continued. Some practical notes. 380 Concrete stairway and steps. 387 Cast concrete stairs. 389 Test of steps:. 390 Concrete stairs formed in situ. 391 Setting out old stairs. 391 Nosings and risers. 392 Framing staircases . 394 Centring for landings and soffits. 396 Waterproof centring. 397 Staircase materials . 399 Filling in stairs. 400 Finishing stairs . 404 Non-slippery steps.. 405 Striking centrings . 405 Concrete and iron. 406 Setting concrete soffits. 408 Fibrous concrete . 408 Polished soffits . 409 Concrete staircases and fibrous plaster. 410 Dowel holes. 410 Cast steps . 411 Treads and risers. 412 Closed outer strings. 413 Concrete floors . 413 Plaster floors . 415 Joist concrete floors. 416 Caminus concrete cement. 417 Concrete floors and coffered ceilings. 418 Combined concrete floors and panelled ceilings. 419 Concrete and wood. 420 Concrete drying. 421 Concrete slab floors. 423 Construction of slab floors. 425 Hollow floors . 427 Concrete roofs . 428 INDEX 519 PAGE CEMENTS AND CONCRETES.—Continued. Notes on concrete. 429 Cast concrete . 431 Concrete dressing . 432 Mouldings cast in situ. 438 Modelling in fine concrete. 443 Concrete fountains . 446 Concrete tanks . 446 Concrete sinks. 448 Garden edging . 448 Concrete vases. 448 Concrete mantel pieces. 449 Colored concrete. 449 Fixing blocks .. 452 Typical system of reinforced concrete construc¬ tions from various sources. 452 Columns and piles. .. 458 Floors, slabs and roofs. 468 Beams . 469 Arches . 471 Lintels . 473 Concrete walls . 475 Strong rooms . 475 Concrete coffins and cementation. 475 Tile fixing. 477 Setting floor and wall file. 479 Foundations . 479 Lime mortar..'. 480 Concrete. 480 For floors. 480 For wood floors. 480 In old buildings. 481 For hearths . 482 For walls . 484 Cement. 486 Sand. 486 Mortar . 486 520 INDEX CEMENTS AND CONCRETES.—Continued. Soaking . Tiles for doors. Ceramics . Files for walls and wainscoting. Floating wall tile.. Buttering wall tiles.’ Hearth and facing tile. Cleaning. Cutting of tile. Tools. Laying tile on wood. Good concrete. Reinforced concrete. PAGH 486 486 488 490 491 491 492 492 492 492 498 495 500 Standard American Locomotive - Engineering —■ COMPLETE IN ALL ITS BRANCHES Including; Railroad Signaling;, Block System, Breakdowns, Valve Setting, Air Brakes, with Complete Questions and Answers By C. F. SWINGLE and W. G. WALLACE Over four volumes in one. Bound in full Persian Morocco, with flap, pocketbook style, stamped in gold. Full gold edges. 1,150 pages. Fully illustrated. It contains: MODERN LOCOMOTIVE ENGINEERING, Twen¬ tieth Century Edition, with Questions and Answers. By C. F. Swingle. Retail price $3.00. RAILWAY SIGNALING AND STATION WORK. By W. G. Wallace. Retail price $2.00. STANDARD EXAMINATION QUESTIONS AND ANSWERS, for Firemen. By W. G. Wallace. Retail price $1.50. MODERN AIR BRAKE PRACTICE, Its Use and Abuse, including the new E. T. Equipment. By Frank H. Dukesmith. Retail price $1.50. 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STANDARD AMERICAN CAS AND OIL ENGINE, AUTOMOBILE AND FARM ENGINE GUIDE A Complete Encyclopedia of the Construction, Operation and Management of Gas Engines, Gaso¬ line Engines, Automobiles, Farm Engines and Trac¬ tion Engines, together with Complete Questions and Answers. By Stevenson & Brookes. Three volumes in one. Over 600 pages. Fully illustrated. Bound in Full Persian Morocco, with flap, pocketbook style. Contains: PRACTICAL GAS AND OIL ENGINE HAND BOOK, including stationary, marine and portable gas and gasoline engines. By L. Elliott Brookes. Retail price $1.50. THE AUTOMOBILE HAND BOOK. By L. Elliott Brookes. Retail price $1.50. FARM ENGINES AND HOW TO RUN THEM, AND THE TRACTION ENGINE. By James H. Stevenson. Retail price $1.00. GAS AND OIL ENGINES. AUTOMOBILES. FARM ENGINES, TRACTION ENGINES AND HOW TO RUN THEM. HOW TO RUN A THRESHING MACHINE. QUESTIONS AND ANSWERS. TPIIS WORK IS PROFUSELY ILLUSTRATED. 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