Roofing felt is a substance composed largely of hair saturated with an asphalte composition, and should be chosen more for closeness of texture than excessive thickness. It is sold in rolls 2 ft. 8 in. wide and 25 yd. long, thus containing 200 ft. super in a roll. Before the felt is laid on the boards (¾ in. close boarding), a coating composed of 5 lb. ground whiting and 1 gal. coal tar, boiled to expel the water, is applied, while still slightly warm, on the boards themselves; the felt is then laid on, taking care to stretch it smooth and tight, and the outside edge is nailed closely with ⅞ in. zinc or tinned tacks. The most common application to a felt roof is simple coal tar brushed on hot and sprinkled with sharp sand. It is not well adapted to dwellings.
Dachpappe is a kind of asphalte pasteboard much employed in Denmark; it is laid on close boarding at a very low pitch, and forms a light, durable covering, having the non-conducting properties of thatch. It is sold in rolls 2 ft. 9 in. wide and 25 ft. long, having a superficial content of 7½ sq. yd., at the rate of 1d. per sq. ft. When laid, it requires dressing with an asphalte composition called “Erichsen’s mastic,” sold at 9s. 9d. per cwt., 1 cwt. of the varnish sufficing to cover a surface of 65 sq. yd.
Willesden paper is another extremely light, durable, and waterproof roofing material, which differs essentially from the 2 preceding substances in needing to be fixed to rafters or scantling, and requiring no boarding on the roof. It is a kind of cardboard treated with cuprammonium solution, and has become a recognized commercial article. It is made in rolls of continuous length, 54 in. wide, consequently, when fixing the full width of the card (to avoid cutting to waste), the rafters should be spaced out 2 ft. 1 in. apart from centre to centre, so that the edge of one sheet of card laid vertically from eaves to ridge will overlap the edge of the adjoining sheet 4 in. on every alternate rafter.
By far the most important and generally used roofing material in this country is slate. Its splitting or fissile property makes it eminently useful as a roofing material, as, notwithstanding the fact that it is one of the hardest and densest of rocks, it can be obtained in such thin sheets that the weight of a superficial foot is very small indeed, and consequently, when used for covering roofs, a heavy supporting framework is not required. Slate absorbs a scarcely perceptible quantity of water, and it is very hard and close-grained and smooth on the surface; it can be laid safely at as low a pitch as 22½°. In consequence of this, the general introduction of slate as a roofing material has had a prejudicial effect upon the architectural character of buildings. The bold, high-pitched, lichen-covered roofs of the middle ages—which, with their warm tints, form so picturesque a feature of many an old-fashioned English country town—have given place to the flat, dull, slated roofs. The best roofing slate is obtained from North Wales, chiefly in the neighbourhood of Llanberis. Non-absorption of water is, of course, the most valuable characteristic; an easy test of this can be applied by carefully weighing one or two specimens when dry, and then steeping them in water for a few hours and weighing them again, when the difference in weight will of course represent the quantity of water absorbed. The light-blue coloured slates are generally superior to the blue-black varieties. (J. Slater.)
Some architects bed the roofing slates in hydraulic cement, instead of having them nailed on dry in the usual way, which leaves them subject to be rattled by the wind, and to be broken by any accidental pressure. The cement soon sets and hardens, so that the roof becomes like a solid wall. The extra cost is 10 or 15 per cent., and it is good economy, considering only its permanency, and the saving in repairs; but, besides this, it affords great safety against fire, for slate laid in the usual way will not protect the wood underneath from the heat of a fire at a short distance.
Tiles are much used in some districts, and are often made of a pleasant tint; but a great objection to all tiles is their porosity, which causes them to absorb much water, rotting the woodwork and adding to their own already considerable weight.
Metallic roofing embraces sheet copper, sheet zinc, sheet lead, “galvanised” iron, and thin plates of “rustless” (Bower-Barff) iron. These materials are only used on flat or nearly flat spaces.
Floors.—Tiles or flags are most frequently used for the floors of kitchens, sculleries, and lobbies. They serve this purpose very well, as they are easily washed and not likely to be injured, but the joints should be made impervious to moisture. In some parts of the country, concrete is used; this answers very well for the same purpose, but it is not good for bedrooms, as it is so cold to the feet. Wood makes the most comfortable floor for sitting or bed rooms, and the best is hard wood capable of bearing a polish. From its convenience and cheapness, common deal is used very generally, and too often in a damp and unsound state, so that the boards shrink and wide gaps are left between. This allows all the foul air from any space—as a cellar or a cavity between the floor and the soil—to ascend into the room. The boards ought to be as close together as possible, and any spaces left between them should be packed tightly with oakum. If this is done, the floors may be stained and varnished, when they can be swept and rubbed clean, and do not require such frequent washing as the ordinary unvarnished floors. This is an important gain, for there is no doubt that emanations rising with the damp from newly-washed floors are often most injurious. If a varnished floor is washed, it dries almost at once. Spaces must be left under the floors, on the ground level, if they are of wood, or they will soon decay; and they ought to be well ventilated. Ceilings, leaving a space between them and the boards of the room above, have come into use, most likely to deaden sound. They often fail of this, while affording fine playgrounds to mice, and even rats. Well-laid boards, of sufficient thickness, and plugged with oakum, would, as regards health, be preferable. (Dr. Simpson.)
General Arrangement.—The chief points to be insisted on in a dwelling are enumerated by Simpson as follows:—Every room should obtain light and air from the outside, and there should be free communication from front to back, so that a current of air may pass through the house. What are called back-to-back houses are very objectionable, and to be carefully avoided. If there is a closet attached to the house, it should, as a matter of course, be ventilated by a window opening both above and below, and, if possible, should be built in a projecting wing or tower, and have double doors, with space between them for a window on each side, so as to have cross ventilation. When there is no closet in the house, it should be completely detached from it, and all piggeries, middens, &c., should be as far removed as possible. Speaking even of large houses, Eassie remarks that they are often very faultily planned in respect to the position in that portion of the interior which is usually appropriated to sinks and water-closets. In the basement, for instance, closets are often placed almost in the middle of the house, and the same mistake is committed on the floors above, a worse error by far; because then the closet would be placed on the landing of the stair opposite the best ground-floor, and chamber-floor rooms—the only ventilation from the closet-rooms being into the staircase, and consequently into the house.