ASPHALT SHINGLES
Asphalt shingles
are the most commonly used and among the least expensive of materials available for steep slope applications. They are very durable and are available in a wide variety of colors and textures.
Asphalt shingles consist of either an organic (wood fiber or cellulose) or fiberglass mat which has been saturated with asphalt and covered with colored mineral granules. In climates where fungus growth is a potential problem, granules treated with algicide are available. "Self-sealing" shingles have an additional strip of adhesive on the underside. The adhesive is activated by the sun's heat after installation and "seals" each shingle to the one below it, providing extra wind uplift resistance for the roof system.
Shingles were once available in only one thickness, but today many manufacturers offer shingles where several layers have been laminated together to produce three-dimensional profiles and appealing shadow lines. These are known as "dimensional" or "architectural" shingles.