Many types of roofing are available – asphalt or asbestos-cement shingles, roll roofing, galvanized steel, aluminum, wood shingles, slate, and others. They vary in durability, fire resistance, insulating value, and other properties. Make your own selection carefully, whether you are covering a new building or re-roofing an old one. Some important considerations in selecting roofing are roof slope, weight of roofing material, cost, fire resistance, appearance, and location. Slope For each different type of roofing, there is a minimum roof slope using the standard end or side lap. If the slope is less than the minimum, there can be serious damage from leakage. Weight Roofingmaterials vary in weight. If the roofing is too heavy for the framing, sagging may occur. A roof that sags is unsightly and hard to keep repaired. Cost Roofing materials vary widely in price. Cost in roofing, however, involves more than the cost of materials. Labor, decking, scaffolding, and other factors make up a large part of the cost. In selecting roofing from the standpoint of cost, keep these points in mind: 1. Good quality, long-lived roofing should be used on permanent building, even though the first cost is high. If maintenance, repair, and replacement are considered, low-quality roofing can be more expensive in the long run. 2. Long-lived roofing is warranted when the cost of applying the roofing is high in comparison with the cost of the materials, or when access to the roof is hazardous. 3. Near a supply center, good quality roofing may be available at lower-than-normal cost. For example, slate, one of the most durable roofing materials, usually is one of the most expensive. However, near the quarry, the price may be comparable with that of lower quality, less-durable roofing. Fire Resistance Roofing materials vary in fire resistance. Slate, asbestos-cement shingles, and metal roofing are the most fire resistant. Others, such as asphalt shingles and roll roofing, provide satisfactory protection if they are of good quality and are kept in good condition. Your house and other important buildings on your property should have a fire-resistant roof covering, if possible. Buildings closely grouped together—less than 150 feet apart—also should have fire resistant coverings. If one catches fire, the danger of fire from flying sparks to the other buildings will be minimized. Location Along seacoasts the air is saturated with salt: around industrial works it may be polluted with fumes. The salt and fumes may corrode galvanized or aluminum roofing and shorten their life. Steel roofing, even though galvanized, is particularly susceptible to such corrosion. If used, it must be kept well painted. For maximum service and protection, install the roofing properly and keep it in good repair. Improper installation and poor maintenance can result in leaks or other trouble and can shorten the life of the roofing.