Page:Encyclopædia Britannica, Ninth Edition, v. 4.djvu/513

TILING.] BUILDING 463 support from the main one, and the cavity has to be ventilated, artltion Besides the outer or main walls of a house, there are alls - interior walls, or partitions as they are called. Thes a in large structures are always executed in brickwork ; in smaller ones they are usually constructed of timber ; and these timbers are often filled in between the uprights by brickwork formed of bricks laid Hat or on edge according to the thickness of it. A plate of wood is occasionally introduced to strengthen the work, which is then plastered over This is called a brick-nog partition. In many of the model lodging-houses in London the partition walls have been constructed a half brick in thickness in good mortar, for the whole height of the building, the floor joists being fixed against them to steady them. , ollow Another sort of wall consists of two skins of brickwork alls. w ith a few inches between them ; this is called a hollow wall. The two skins, either both of half a brick thick, or the outer one of one brick and the inner one of half a brick, are tied together by iron band-ties at various intervals. These when straight are sometimes found to transmit the wet blown through the outer facing to the inner one, so a bend or loop is formed in the centre of the tie, which throws oft the water. This hollow space tends to make the houses both dry arid warm, but it is said to form receptacles for insects, &c. An addition to such walls has been lately made by a series of these looped ties supporting a course of slates placed not quite vertical but sloping back slightly. The next course of ties is built in at such a level that it fixes the top of this first course of slate in place, and pro vides a starting for the next course. Thus, in the heart of the wall there is a continuous surface of slates, slightly overlapping at joists and at beds, and so placed that what ever moisture blows through the outer skin is not able to penetrate, but will trickle down the slates to the bottom of the cavity in the hollow wall. This is one of the many building patents of Mr John Taylor. iterials A rod of brickwork will consume about 4500 bricks, (1 labour though the number will be a few more or less than this, ckwork as ^ ie Bricks happen to be below or above the average size, and as the joints are made thicker or thinner. The quantity of mortar, it is evident, will be affected by the latter consideration also ; but in London it is generally reckoned at from ninety to a hundred striked bushels to the rod, or from four to four and a half cart-loads, each containing about one cubic yard. The labour on a rod of brickwork may be done on an average by a labourer in four days ; this, however, does not include making and turning the mortar, nor scaffolding. Many things will, however, affect the time in which the work may be performed, both of the bricklayer and his labourer ; the former can do one-fourth as much more, at the least, in walls which are to be plastered, as in those in which he has to keep the perpends and draw the joints, &c., and more in thick walls than in thin ones ; and the capability of the latter will depend, inversely, on the rate at which the former can proceed, on the distance he may have to carry the bricks and mortar to the foot of the ladder, and mainly on the height he has to carry the materials up the ladder. In great heights, however, the materials should be hoisted. I of tiling. Tiling being much less in vogue than formerly, in con sequence of the better appreciation of the superior qualities of slate for covering roofs, and the moderate cost at which slates are now furnished to the builder, it no longer maintains its separate artificer, but is performed, when it is required, by the bricklayer. Tiling is for the most iin tiles, part of two sorts plain tiling and pantiling. Plain tiles are simple parallelograms, generally about 10| inches in length, 6 inches wide, and -| of an inch thick ; and each tile has a hole pierced through it near one end, to receive the oak pin by which it is hooked to the lath. The tiles are laid in mortar and sometimes in hay, or moss, on the laths, which in England are of oak or fir, with an overlap of 6, 7, or 8 inches. The greatest overlap or smallest gauge makes the securest work, though it does not present so good an appearance externally as a longer gauge does ; and it requires, moreover, a greater number of tiles and laths, thereby adding materially both to the weight and the cost. The great overlap and the mortar (or hay or moss) are both necessary to prevent the rain and snow from driving in between and under the tiles, especially when of a low pitch. Plain tiling requires the pitch of the roof to be at an angle of at least 50, and is one of the heaviest coverings that can be used, though it is at the same time one of the warmest. The tiles, however, readily and rapidly absorb moisture, which they communi cate to the laths and rafters under them, to the serious injury of both the latter; and the mortar in which they are set requires to be frequently pointed, the constant atmospheric changes to which it is exposed occasioning it Other de- to crumble and fall away in no long time. Terro-metallic scriptions tiles are made with projections at the back to catch on the of tilin S- laths, in lieu of pegs. Italian tiles have been made in England since about 1840, and are occasionally used. They are slightly curved, fit easily one into another, and have a horizontal indentation across the upper part to prevent the wind drifting the rain over the head of the tile. They have either wide or narrow vertical rolls. Taylor s new roofing tiles have a plane surface with slightly turned up edges at the sides, and a lump on the surface near the upper edge to prevent the upper tile slipping. The cover tile is of a similar size and form. They are recommended as half the weight of the common tiling ; they are about as light as slating, and may be laid to nearly as flat a pitch, pantiles. Pantiles are parallelograms of irregular surface, straight in the direction of their length, which is 13i inches, but twisted in the transverse section. Measuring the whole surface across, a tile is 9 inches wide, but in a right lino from point to point not more than 7, and its thickness is half an inch ; a small tongue or lip is bent down at one end from its flatter convexity, on the under side, to hook it to the lath by, instead of a wooden pin through it, as in a plain tile. Pantiles are set dry or in mortar, on laths. They are not laid side by side, but overlap laterally as in fig. 8 ; consequently all the overlap they have longitudinally is 3 or 4 inches only, or enough to prevent rain and snow from driving up under the upper, over the end of the lower tile ; and hence pantiling is but little more than half the weight of plain tiling. It is, however, a much less warm covering for houses, and is more liable to be injured by violent gales or gusts of wind than the latter is; but again, it presents a far more pleasing appearance to the eye. Pantiling will not bear a much flatter pitch than the other. It is greatly improved by being pointed on the inside with lime and hair. Sometimes, indeed, the whole of the work is, as we have said, set in mortar ; but this mode has disadvantages to which pointing internally is not liable, and its superiority in other respects is questionable. In both pan and plain tiling large concave tiles are used to cover the hips and ridges of a roof. These are not generally made to overlap each other in any situation, but arc set in mortar, and fastened with nails and hooks fitted for the purpose, and driven into the woodwork of the roof. In addition to these an ornamental ridging or cresting is often introduced. A variety of

patterns are now made for this purpose. Another form of