What are asphalt shingles, and do shingles have asphalt?
Short answer. Asphalt shingles are roofing shingles made from a fiberglass mat soaked and coated in asphalt, topped with ceramic-coated mineral granules, with a sealant strip that bonds each course to the one below. They are the most common roof on Georgia homes and come as flat 3-tab, dimensional architectural and heavier designer styles.
What is inside a shingle
- Fiberglass mat: the core that gives the shingle strength. Older shingles used an organic felt mat, which has been phased out.
- Asphalt coating: the waterproofing layer, blended with fine mineral filler for durability and fire resistance.
- Granules: crushed stone coated with ceramic color. They shield the asphalt from sunlight, give the roof its color, and on algae resistant shingles include copper that discourages black streaks.
- Sealant strip: a line of heat-activated adhesive that softens in the sun and glues each shingle to the one below, which is what keeps them down in wind.
- Back surface: sand or a mineral coating so bundled shingles do not stick together, plus a release film strip over the sealant.
Types of asphalt shingles
A 3-tab shingle is a single flat layer cut into three tabs. An architectural shingle bonds two layers together for a thicker, shadowed look and longer life. Designer shingles stack more material to imitate slate or wood shake. Some impact resistant shingles use SBS modified asphalt, a rubberized blend that flexes rather than cracks.
So do all shingles have asphalt?
No. Shingle describes the shape and overlapping installation, not the material. Wood shakes, slate, metal shingles and synthetic composite shingles contain little or no asphalt. In Georgia, though, nearly every house with a shingle roof has asphalt shingles because they balance cost, appearance and storm performance well.
See architectural vs 3-tab shingles and roof anatomy explained.