Mortar (building material)

“ The mortar should contain the minimum of water which will permit it to work freely, and when the mortar is used it should be solidified, that is, pushed together by means of a trowel or by the material which is laid upon it. ”

“ Government specifications for fireplace mortar, which must be used in laying all work except the fire brick, are as follows: hydrated lime, nine pounds to each 94-lb. bag of Portland cement; mix this with three times its volume of clean sand and enough water to make a smooth workable mortar. Wet all stones before applying the mortar. Don’t use ordinary lime mortar for fireplaces and chimneys.
Construction of the flue is the next important matter. ”

“ The brick-arching is also very liable to fall, especially if only four and a half inches thick, independently of the weight which may be placed upon it, for it is not uncommon after a fire in a large building, to find the mortar almost completely pulverized to the depth of three inches, or four inches, from the face of the wall. ”

“ To a casual observer mortar is mud, but to a builder who understands the chemistry of mortar it is a compound of water, lime and sand, and when properly prepared forms an indestructible cement. Fresh slacked lime, when brought in contact with clean, sharp sand, adheres strongly to the surface of each grain, and forms the silicate of lime. ”

“ The by-laws dated 1891, made by the London County Council under section 16 of the Metropolis Management and Building Acts Amendment Act 1878, require the proportions of lime mortar to be one to three of sand or grit, and for cement mortar one to four. Clean soft water only should be used for the purpose of making mortar.
Grout is thin liquid mortar, and is legitimately used in gauged arches and other work when fine joints are desired. In ordinary work it is sometimes used every four or five courses to fill up any spaces that may have been inadvertently left between the bricks. ”

“ If the mortar be too thick, extra labour is involved in its use, and much time wasted. If it be so thin as to run easily from the trowel, a longer time is taken in setting, and the wall is liable to settle; also there is danger that the lime or cement will be killed by the excess of water, or at least have its binding power affected. It is not advisable to carry out work when the temperature is below freezing point, but in urgent cases bricklaying may be successfully done by using unslaked lime mortar. ”

“ Even if fresh lime and sharp sand are used, in accordance with the usual specifications in building contracts, the mortar bond may still be weak by reason of careless or imperfect mixing. All mortar, even that used for laying stones and bricks, should be mixed until a lime film surrounds every particle of sand. Plastering the outside of the wall below the grade line and pointing the wall above cannot make a firm, good wall out of one which has been carelessly laid or one bedded in inferior mortar. ”

“ But, perhaps, the worst of all mortar is that wherein very fine pit-sand, containing a portion of earthy matters, is used, and when the whole is mixed up with impure water. So little attention is often paid to the quality of mortar, in common buildings, that one would imagine it were applied, as if intended more to prevent the sifting winds from penetrating the walls, than as the medium by which they were ultimately to be bound or formed into a compact fabric. ”

“ For mortars of six, eight, or ten inches diameter, the serpents should be made in one and two ounce cases, six or seven inches long, and fired by a leader, brought out of the mouth of the mortar, and turned down the outside, and the end of it covered with paper, to prevent the sparks of the other works from setting it on fire. For a six inch mortar, let the quantity of powder for firing be two ounces ”

“ But, for general use as a mortar, it would not only have been expensive, but often highly inconvenient in building, from the speedy manner in which it hardens. It is also of too brittle a nature to be suitable for the general purposes of common mortar; though it forms a paste of great value for lipping or pointing the outward joints of water buildings, not only by preserving the mortar till it gets into a fixed state, but also as forming a durable joint. A considerable supply of this cement was accordingly used throughout the building, for pointing the exterior joints. ”

“ To obviate this tendency to settle and thus cause the bulging of the face or failure of the wall, the mortar used should be composed of Portland cement and sand with a large proportion of the former, and worked as stiff as it conveniently can be. In building such work the stones should be in height equal to an exact number of brick courses. It is a common practice in erecting buildings with a facing of Kentish rag rubble to back up the stonework with bricks. ”

“ A common iron mortar, such as is used by druggists and apothecaries, is found to answer very well for grinding or pounding the brimstone, charcoal, salt-petre, &c. separately; and apothecary’s close sieves, fitted with wire-cloth, are the best possible implements for obtaining the fire powder; but when corn gunpowder is to be mealed, or the various ingredients are to be mixed together, such mortars cannot be used, as the heat generated by the continued action of the pestle might inflame the mixture, and thereby place the life of the operator in imminent danger. ”

“ As in wood or stone, though in less degree, there is a kind of natural grain, even in the unnatural material, strengthened by oiling, but softer and richer than any painted surface. There seems to be no evidence that the mortar is injured by proper coloring-material,—mineral paints, or even lampblack, if you like it; I don't. Whether you like it or not, you are not to use white mortar for the outside work. Unless, indeed, you propose to build of pressed brick, in which case you will need it to show your neighbors how fearfully and wonderfully nice you are. ”

“ Only the chimney remains as its monument. Slowly, little by little, the patient solvents that find nothing too hard for their chemistry pick out the mortar from between the bricks; at last a mighty wind roars around it and rushes against it, and the monumental relic crashes down among the wrecks it has long survived. ”

“ When water alone is to be dealt with, and especially when it is liable to act with force, mortar is necessary for securing to every block in the structure its own full weight, and the aid of every other collateral and superimposed stone, in order to resist the loosening effect which water in powerful action is bound to produce.
In the application of construction to any particular object, the nature of the object will naturally affect the character of Particular objects of construction. ”

“ For setting fire-bricks fire-clay is always used. Pargetting for rendering inside chimney flues is made of one part of lime with three parts of cow dung free from straw or litter. No efficient substitute has been found for this mixture, which should be used fresh. A mortar that has found approval for tall chimney shafts is composed by grinding in a mortar-mill one part of blue lias lime with one part each of sand and foundry ashes. In the external walls of the Albert Hall the mortar used was one part Portland cement, one part grey Burham lime and six parts pit sand. ”

“ There is also a kind of land-mortars, mounted on travelling carriages, invented by count Buckeburg, which may be elevated to any degree; whereas the British as we have already stated, are fixed to an angle of 45 degrees, and are firmly lashed with ropes.
Partridge Mortar, is a common mortar, surrounded by 13 other little mortars, bored round its circumference in the body of its metal. The centre one is loaded with a shell, and the others with grenades. The vent of the large mortar being fired, communicates its fire to the small ones; so that both shell and grenades go off at once. ”

“ The mortar, used in laying bricks and common stone, has a greater proportion of sand, which is generally of an inferior quality. Besides, the materials are incorporated with less care. Lime for the purposes of building is procured chiefly by calcining limestone in a kiln, with wood, coal, or some other combustible substance. It is also obtained by burning chalk, marble, and marine shells. Water poured upon newly-burnt or quick lime, causes it to swell, and fall to pieces into a fine powder. ”

“ We find various mixtures and preparations of mortar used in the station:—
(1) A brownish sort, rather coarse and more friable and earthy and inferior, used in the lower courses of the foundation walls, mixed with mould and humus and gravel and sand.
(2) A whitish cement, mixed with small-sized clean river gravel, poured between the blocks of red sandstone and the facings, as seen in the walls of the prætorial building.
(3) A fine cement, made of broken bricks and lime, used for the floorings of the hypocaust. ”

“ The primary cause of the premature decay which sometimes takes place in mortars and like material is due to the presence of mud and decayed vegetable and animal matter in the sand, or possibly in the lime or cement itself. It is therefore of great importance to use a perfectly clean sand for the aggregate, and to select a lime or cement of good quality for the matrix, Decay of Mortar. care being taken that no foreign matters detrimental to the mortar be introduced during the processes of preparation. ”

“ Even the cements deteriorate somewhat with age, and the common stone lime is often used after it is partially or entirely air-slaked. If the binding material be inferior and the sand have quantities of fine earth or vegetable matter mixed with it, it will be seen how impossible it is to secure a strong and binding mortar. ”

“ From the elevated position of the building, the mortar gallery on the beacon was now much lower, and the lime-buckets were made to traverse upon a rope distended between it and the building. On occasions like the present, however, there was often a difference of opinion between the builders and the mortar-makers. John Watt, who had the principal charge of the mortar, was a most active worker, but, being somewhat of an irascible temper, the builders occasionally amused themselves at his expense ”

“ The practice of our masons of putting the blood of oxen into mortar was no doubt in the first instance associated with the idea of a sacrifice; however this may be, the blood had no doubt a real effect in hardening the mortar, just the same as treacle, which has been known to be used in our days. The use of cement when any extra strength is needed has put aside the use of either blood or treacle in the mixing of mortar. ”

“ Other remains again are shapeless masses, or mere traces of foundations, some in the sea, and some on land, and so numerous, so mixed, and so confused, that it would be hardly possible to mark what belongs to one edifice, and what to another. Some of them indeed are so deeply buried in the hill, that they seem rather the productions of nature than of art: the prevailing style of workmanship is rubble, faced with a reticulated work of very soft stone, which is less durable than the mortar which cemented it, and yet the mortar here is seldom very good ”

“ The brickwork around all fireplaces and flues should be laid with cement mortar, as it is more resistant than lime mortar to the action of heat and flue gases. It is well to use cement mortar for the entire chimney construction. ”

“ The Indians use it freely in laying their walls, as freely as our masons use lime mortar; and although it never acquires the hardness of cement, it disintegrates slowly. The mortar in these walls is still sound, so that it requires some effort of strength to loosen a stone from the wall and remove it. But this adobe mortar is adapted only to the dry climate of Southern Colorado, Arizona, and New Mexico, where the precipitation is less than five inches per annum. The rains and frosts of a northern climate would speedily destroy it. ”

“ The mortar is placed in a hole, dug in the ground, a few inches left standing out; the earth is shovelled in, and driven down firm; a penthouse lid, to keep out rain, dirt, and insects, renders it complete. Amateurs require nothing of this kind. A small mortar may be a tube, open at both ends, and fitted with a wooden bottom, to which it is to be firmly screwed. Fig. 94 represents such mortar: it may be 4 diameters high; and the foot should have a conical hole turned in it to receive the cone fastened to the shell. ”

“ If the flashing is sound, possibly water runs down the inside of the flue and through defective mortar joints. Where these cannot be reached readily, the chimney may have to be torn down and rebuilt. Sometimes a hood (fig. 18, A and B) is built on top of the chimney to keep out water or to prevent wind blowing down it. To prevent dampness being drawn up from the ground, the mortar can be raked from a joint at least 12 inches above the ground and a layer of slate, asbestos shingles, or rust-resistant sheet metal and new mortar worked into the joint. ”

“ Pure white joints are obtained by using white sand or ground limestone or marble. As the color of the mortar greatly affects the appearance of the finished wall, much care should be given to the selection and proper use of these colors, whether natural or artificial. As the color of the finished mortar after it has set and dried is never the same as that of the fresh mortar, experience is the only guide for the proper preparation of the mortar. Someone has well said that the right way to make mortar is to mix brains with it. ”

“ It was intended that one 13-inch mortar, of enormous weight, should be put upon each, that these mortars should be fired with twenty-three pounds of powder, and that the shell thrown should, at a distance of three miles, fall with absolute precision into any devoted town which the rebels might hold on the river banks. The grandeur of the idea is almost sublime. ”