covering, materials, roofs
There are different covering materials for roofs:1) Corrugated sheets — that is, corrugated iron or steel, black galvanized or with protective coatings. This material is very suitable for the roofs of storage buildings, and buildings of a temporary character;
2) Aluminum — aluminum sheets and rolls as a light material having insulation properties are largely used. They must be applied to a roof cover using aluminum nails with screw shanks.
3) zinc — it is a material largely used as a roof covering, strong durable, and light and rather cheap. It is usually supplied in sheets and may be in corrugated form Zink sheets are 7 ft. or 8 ft. long be 3 ft. wide, weighing from 1.
1/2 or to 25 oz. per square foot; 4) Lead — sheet lead forms a much heavier roof covering than other sheet metals, but it lasts much longer and more easily with stands the attacks of polluted air. Lead must be laid on a close boarding, because it is very ductile; 5) Slate — it is a strong and very impermeable material, it can be easily split into thin plates suitable to laying, and its cost is rather low. Slates are cut to many different sizes, varying in length from 10 in. to 36 in. and in widths from 5 in. to 24 in. The rule for using different sizes is that the steeper the pitch, the smaller the slate and vice versa. Slates may be fixed by nailing at the head or about the middle; 6) Tile — tiles for roofs are made from clay and baked in a kill like bricks; they produce a strong and non-porous covering. Tiles may be of many colours and tints from yellowish-red, red and brown to dark blue. Their quality depends on the burning — under burned tiles are weak, porous and liable to decay; overturned tiles will cause warping and variations in colour. Insulation is an integral part of the roof assembly of buildings For the purpose of reducing the conductivity of the roof assembly, a low density material composed of vegetable fibres, cork glass fibres, or mineral wool are formed into "rigid" units, semirigid units or flexible strips.
