Composition Shingles
These products account for as much as 80 percent of the residential market. Usually called asphalt shingles, they're split into two broad categories: organic and inorganic. The terms refer to the base mat of the shingles, the part that holds the asphalt and mineral granules. Organic shingles have a "felt" base mat made of cellulose fibers, wood chips, or recycled corrugated cardboard. Inorganic shingles have a fiberglass base mat.
Characteristics. The differences in base mats affect fire rating and how the shingles will perform under certain conditions. For example, the fiberglass in inorganic shingles allows them to earn a Class A fire rating. It also tends to make these products the stronger of the two. Organic shingles have a Class C rating, but they tend to be easier to install and provide better tear and wind resistance in extremely cold weather. Some manufacturers offer a fiberglass shingle with a special polymer-modified asphalt, making the product more pliable and stronger in cold weather.
Styles. You'll hear standard asphalt shingles referred to as three-tab, because they come in a strip with notches that create what appears to be three separate shingles. Premium products are called "architectural" or "dimensional" shingles. These thicker, often laminated shingles cast shadow lines like a thick wood shake. The result is a rich, textured appearance rather than the flat surface of standard three-tab shingles.
All asphalt shingles are coated with a layer of mineral granules that protect the shingle from sunlight, add color and, in some cases, help resist algae and fungus growth. Manufacturers can discourage unwanted plant life by adding copper or zinc to the granule mix. If you live in a hot, humid climate, look for algae-resistant shingles.
Cost. Asphalt shingles are at the low end of the price scale. Good-quality asphalt products backed by 20- to 30-year warranties are available for $25 to $30 per square. Architectural shingles run to about $60 per square and come with 40-year warranties. Figure on an installed cost for midlevel shingles of $50 to $100 per square.
