| SCRATCH-COAT PROPORTIONS | |||
| Hydrated lime | 133 | parts | by weight |
| Sand | 400 | “ | “ |
| Hair | 1 | part | “ |
| BROWN COAT | |||
| Hydrated lime | 100 | parts | “ |
| Sand | 400 | “ | “ |
| Hair | ½ | part | “ |
| FINISHED COAT | |||
| Smooth Finish | |||
| 1 part by volume of calcined gypsum. | |||
| 3 parts“lime paste. | |||
Metals
The most used metal in the small house is the so-called tin-plate or roofing tin. It is not a true tin-plate, for it contains 75 per cent lead and 25 per cent tin, applied to a base of soft steel or wrought iron. It comes in two grades, IX and IC, the former being No. 28 gauge and the latter No. 30 gauge. The lighter is used for roofing and the heavier for valleys and gutters. The tin does not entirely protect the base metal, so that it is necessary to paint both sides before it is applied.
Galvanized iron is another form of sheet metal which is extensively used for work on the small house. It consists of sheet iron or steel, covered with zinc. This coating should be free from pinholes or bare spots, and of a thickness to prevent cracking or peeling. If the coating is sufficient and well done, it is superior in lasting quality to the ordinary tin-plate.
Copper, since the war, has come back into use again as a sheet metal for the small house, for its cost has dropped within reason. In order to meet a certain popular demand a light grade of copper sheet roofing has been placed on the market, although it has generally been considered that sheets weighing less than 16 ounces per square foot were not suitable for roofs.
Glass
There are two kinds of window-glass used, double thick and single thick. The former is ⅛ inch thick or less, and the latter is ¹/₁₂ inch thick. It is customary to use double thick in all window-panes over 24 inches in size. The grading is AA, A, and B, according to the presence of defects, such as blisters, sulphur stains, smoke stains, and stringy marks.
Plate glass is used only where the expense will permit. It is different from window-glass in that the latter is made from blown glass, while plate glass is made from grinding and polishing down sheets of rolled glass.
There are quite a number of other minor materials which enter into the construction of the small house, but they are more or less identified with the mechanical equipment and the finishing, and will be considered under these headings.
Sheet lead weighing 5 to 6 pounds per square foot is often used for counter-flashing. Leaders and leader heads of cast lead have been made practical by one company, which has developed a method of hardening the lead.