Brick and mortar

“ The mortar they use in building is very like plaister of Paris, which sets very hard, and does very well when all is dry; but as soon as ever water is applied, it all crumbles to powder; and in building walls of four or five feet thick, they have only an outside casing of brick work thus cemented, and within it is filled up with dust and rubbish, so that what seems strong enough in appearance to bear any thing, soon moulders away, and by its own weight accelerates its ruin. ”

“ Editors:—I am satisfied that a great many fires originate through poorly constructed chimneys; and, although not a bricklayer by trade, I would offer a few hints how to construct a fire-proof chimney. Let the bed be laid of brick and mortar, iron, or stone; then the workman should take a brick in his left hand, and with the trowel, draw the mortar upon the end of the brick, from the under side, and not from the outside edge, as is usual. Then, by pressing the brick against the next one, the whole space between the two bricks will be filled with mortar ”

“ When the mortar is dry lay the floor in the usual manner. It takes a long time for fire to burn through a floor laid in this manner, and sound is deadened completely by the mass of non-conducting mortar and the double floors. For fire-proofing and deadening partitions in an effective way, build a four-inch brick wall between the studding. A nail driven every ten or twelve inches in the side of the studding, on the line of the mortar joint, will hold the wall firmly between the studding. Where brick is scarce or expensive, sun dried brick made from stiff clay is a good substitute. ”

“ 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. ”

“ Fracture seldom or never occurs through the solid stone, in masonry, but always at the mortar joints, and generally by their loss of adhesion, to the stone at the faces of the joint. It rarely occurs through the brick, in brickwork, and only when the cohesion of the brick itself, is less than that of the cement. ”

“ In examining the bond in a brick wall, the eye naturally is first attracted to the brick units as so many colored spots arranged in different order so as to produce a certain pattern effect; but this pattern effect in the brickwork depends very largely upon what at first may be overlooked or disregarded, the mortar joint. The mention of mortar suggests in the mind a very commonplace thing which the workman mixes and carries in a hod to the bricklayer; but it is concave one of the most important elements entering into the beauty, as well as the strength, of a brick wall. ”

“ Bricks should not be merely laid, but each should be placed frog upwards, and rubbed and pressed firmly down in such a manner as to secure absolute adhesion, and force the mortar into joints. Every brick should be well wetted before it is laid, especially in hot dry weather, in order to wash off the dust from its surface, and to obtain more complete adhesion, and prevent it from absorbing water from the mortar in which it is bedded. ”

“ With most sorts of brick the outer face absorbs moisture whenever the weather is moist; and in time the action of the rain, and the subsequent action of frost upon the moisture so taken up, destroys the mortar in the joints, which are to be seen perfectly open, as if they had been raked out, in old brickwork, and in some cases (happily not in many) the action of weather destroys the bricks themselves, the face decaying away, and the brick becoming soft.
Against this serious defect in our staple building material a series of precautions have been devised. ”

“ The mortar, and even in some cases the bricks themselves, will rapidly deteriorate if moisture be allowed to get into the heart of a brick wall, and in exposed situations this is very apt to happen. Care should always be taken to keep the pointing of external brickwork in good order, and to maintain all copings and other projections intended to bar the access of water coming down from above, and to stop the overflowing of gutters and stack pipes, which soon soaks the wall through and through. ”

“ As one goes over the inside of the foundation, the searching cold blasts will reveal the crevices that need attention. Mark each one with a wooden splinter as fast as they are found. When all four walls have been thoroughly inspected, the work of closing these cracks can be done as a single operation. Except for a solid brick or stone house, inspect the point at which the sills rest on the foundation walls. The fillet of mortar may have come loose or cracked in places. ”

“ We have all been used to seeing bricklayers tap each brick after it is placed on its bed of mortar several times with the end of the handle of the trowel so as to secure the right thickness for the joint. ”

“ Bricks are always thirsty, and if one is laid in mortar, it will [Pg 38] suck the moisture out of it almost as a sponge will suck up water. The mortar thus has no chance to set, and so is not strong as it should be. That is why the bricklayer wets his bricks, especially in summer, before he puts them in place. Lime or cement mortar will not set in freezing weather, and a brick building put up in the winter is in danger of tumbling down when the warm days of spring arrive. ”

“ 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. ”

“ He studied the best height for the mortar box and brick pile, and then designed a scaffold, with a table on it, upon which all of the materials are placed, so as to keep the bricks, the mortar, the man, and the wall in their proper relative positions. These scaffolds are adjusted, as the wall grows in height, for all of the bricklayers by a laborer especially detailed for this purpose, and by this means the bricklayer is saved the exertion of stooping down to the level of his feet for each brick and each trowel full of mortar and then straightening up again. ”

“ The first course of brick is well bedded in mortar on the footing or the solid ground, as the case may be. At the corners and at proper intervals along the wall where necessary, a few brick, four or five courses high, are laid up in the advance to serve as leads or starting points for the bond and supports for the line which guides the mason to the proper level and alignment of the brick. The mortar is well spread with the trowel along the top of the brick course, and the brick to be laid is firmly pressed down on this mortar bed next the lead. ”

“ The adhesion of common lime mortar varies enormously, with the nature of its materials, the sort of stone or brick which it is used to cement, the thickness of the joints, the care taken to fill them effectually and solidly, the degree of wetness or dryness of the mortar itself and of the stone or brick to which it has been applied, and the rate at which the mortar has been dried during its setting, and the amount of moisture and of air to which it has been subsequently exposed. ”

“ Any serious shock may cause a building of ordinary brickwork to collapse altogether, and from time to time a formidable accident occurs owing to this cause. The fact is, the bricks are each so small compared to the mass of the work, and the tenacity or hold upon them of even fairly good lime mortar is so comparatively slight, that there is really but little grip of one put upon another.
Persons who have to design and construct brick buildings should never forget that they have to be handled with caution, and are really very ticklish and unstable. ”

“ 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. ”

“ These are illustrations of the extent of flexibility in good brickwork, which possesses it in a far higher degree than stone masonry, the bond of the mortar being better, the flexibility greater, both in the brick and thick mortar joints, these very numerous, and the elasticity more nearly alike in both, than in stone masonry. ”

“ With the dark mortar the joints will be visible, modifying the color of the wall, in some cases, perhaps, improving it; while the red will give a more uniform tint, on which not only colored brick or stone will appear to the best advantage, but the lines of the openings and other essential details are brought out in clearer relief. You would perhaps expect coloring the mortar the same shade as the brick to give precisely the effect of painting the entire wall. ”

“ If the spaces between the bricks were always filled with good mortar, it would be better not to plaster the inside of the flues, as the mortar is liable to cleave from the brick, and, hanging by one edge, form lodging-places for soot. As commonly built it is safer to plaster them within and without, especially without, for that can be inspected. The style of the visible part must depend upon the building. One thing lay up in the recesses of your lofty mind: A chimney is most useful and honorable, and you are on no account to be ashamed of it. ”

“ The object of this wetting is to prevent the bricks from absorbing moisture from the mortar which must be allowed to dry slowly so as to obtain a good bond. If they are laid dry, the - 109 - bricks will quickly take up a large amount of water from the mortar, preventing proper setting and adhesion. Water increases the weight of brick and consequently the labor of handling, so that some workmen are inclined to lay them dry. This should not be allowed except in freezing weather, when the conditions require quicker setting. Good mortar bond is essential to a good wall. ”

“ Thus I was brought close to the well-wall, and the marked brick near about the level of my face when I stood up in the bucket. There was nothing to show that this brick had been tampered with, nor did it sound hollow when tapped, though when I came to look closely at the joints, it seemed as though there was more cement than usual about the edges. But I never doubted that what we sought was to be found behind it, and so got to work at once, fixing the wooden frame of the candle in the fastening of the chain, and chipping out the mortar setting with the plasterer's hammer. ”

“ Care should be taken in setting flue linings to be sure that the joints are well cemented and, at the same time, that all spaces between the lining and brickwork are tightly filled with mortar. Any openings in the joints of the tile lining, or even of the brickwork, not only check the draft but are a fire menace. Cement plaster should not be substituted for the flue lining as it is likely to crack and fall off, thus leaving the flue in a dangerous condition. ”

“ In setting firebricks in position, a thin paste of fireclay and water or of material similar to that of which the brick is composed, must be used in place of ordinary mortar, and the joints should be as close as possible, only just sufficient of the paste being used to enable the bricks to bed on one another. ”

“ But where there are no legal requirements, the contractor's own judgment and experience should guide him in the selection of the proper mix, as each one has certain qualities which recommend it. Portland cement mortar is stiffer and harder to work than lime mortar, but should always be used where permanence and strength are required, as in exposed or heavy bearing situations, or in cold weather when the mortar must set before it freezes. ”

“ Stock brickwork in lime mortar crushed under a pressure of 18.63 tons per sq. ft., and in cement mortar under 39.29 tons per sq. ft. Gault brickwork in lime mortar crushed at 31.14 tons, and in cement mortar at 51.34 tons. Fletton brickwork in lime crushed under a load of 30.68 tons, in cement under 56.25 tons. Leicester red brickwork in lime mortar crushed at 45.36 tons per sq. ft., in cement mortar at 83.36 tons. Staffordshire blue brick work in lime mortar crushed at 114.34 tons, and in cement mortar at 135.43 tons.
The height of a brick pier should not exceed twelve times its least width. ”

“ The anchors for the support of the gates should be riveted to this steel beam or angle so that no undue strain will be exerted on the brickwork. The brickwork should always be laid in cement or cement-lime mortar. If ornamental caps are desired, they should be of stone or concrete. On large posts, it is desirable to lay brickwork in some natural bond as this not only increases the rigidity of the post but gives a beautiful effect. ”

“ When the joints are much fewer in proportion, the stone relatively to the mortar, highly elastic and rigid, and the bond, so far as adhesion of the mortar is concerned, small, (indeed, in the case of many hard, siliceous stones, such as granite, almost nil,) the result of this difference is, that a well-built and indurated brick wall, when fractured, breaks indifferently nearly, through joints and bricks ”