In taking the dimensions of the brickwork in the different stories, the height of each part, as high as it goes of the same thickness, must be taken ; and the contents of each part computed the offsets being always below the joists, and consequently the wall the same thickness throughout, from the ceiling of one floor to the ceiling of another.
All apertures and recesses from any of the faces are to be deducted, but an allowance per foot lineal should be granted upon every right angle, whether external or internal, except that two external angles are formed by a brick in breadth, and then only one of them must be accounted for. This allowance is in consequence of plumbing the faces which constitute the said angles ; but if the bricks are cut so as to form oblique angles, this allowance should be at least double.
It is customary, in almost every part of the country, in measuring for workmanship, to find the contents of the walls as if solid, without deducting the vacuities, so that upon this principle, if the apertures be ever so large, they must, at all events, be accounted as solid ; and, iu this instance, the pro prietor would be greatly overcharged by the workman.
Again, in apertures of small breadth, the trouble in plumb ing at the returns is equally the same at the same height as if ever so wide ; but iu ease the voids are less than the lineal allowance, there would be a manifest loss to the master workman. It is much to be wished that such an allowance as above mentioned should be established, in order to do away the uncertainty of computing the quantity of walling, such as to be often above, and sometimes below the real value of workmanship.
Gauged arches are sometimes deducted and charged sepa rately, and sometimes not ; but it is the same whether they are deducted or not, as the extra price must be allowed in the former case, and the whole price allowed in the latter, which is much the more troublesome of the two. Gauged arches are at least five times the trouble of the best marl facing.
To measure the vacuity of a rectangular window.—Find the solidity that would fill the outside vacuity from the face of the wall to the reveal, or outside of the sash-frame ; the solidity that would fill the vacuity from the outside of the sash-frame to the vertical plane of the extension of the back upwards; and the solidity that would fill the vacuity con tained between the vertical plane of the back and the internal face of the wall ; then add these three solidities together, and the sum will be the solidity that will fill the whole void ; then add the allowances.
Or thus—Find the area of each of the three vacuities parallel to the thee of the wall ; • multiply each area by each respective number of half bricks in the thickness of the wall, add the three products together ; divide the sum by 3, and the quotient reduces the contents in superficial feet to the standard thickness.
In taking the dimensions of brickwork, inches are generally neglected.
Example.—Suppose the height of the outer vacuity, from the sill to the under side of the head, to be 10 feet, the breadth 4 feet 6 inches, and the thickness half a brick ; the height of the middle vacuity from the sill to the under side of the wooden lintels, to bp. 10 feet 3 inches, the breadth 5 feet 2 inches, and the thickness also a brick, and the inside vacuity, from the floor to the under side of the said lintels, 13 feet ; the mean breadth, supposing the inside to splay, to be 5 feet 6 inches, and the depth of the recess IL brick : required the solidity that will fill the void.
To calculate the price of a rod of brickwork.—This will depend upon the quality of the bricks and the goodness of the workmanship ; for in building foundations and party walls, which are commonly done with place-bricks, the brick layer may easily lay 1,500 bricks in a day : in garden-walk, barns, and common country houses, where greater nicety is required in jointing, he may lay about 1,000 per day ; and in gray-stock, or marl fronts, done with great care, he will hardly exceed 500 in a day. The expense per rod will also depend upon the articles of living, and consequently upon the times. One example, however, will be sufficient ; the prices of materials and labour may be had from a Price Book. In the Łt4 10 6 In making the calculation of a wall where the bricks of the facing are of a superior quality to the backing, it is pm per to observe, that the number of bricks in the theing of a rod of Flemish-bond work will vary from 1,500 to 2,000, according to the size of the bricks and closeness of the joints; this number of bricks must be deducted from the whole number that would constitute a rod ; and each number of bricks must be valued according to their respective qualities.