Fiberglass base
Fiber glass shingles carry a Class A fire resistance rating from Underwriters Laboratories (UL), the highest fire rating available. Thus, fiber glass shingles are the best protection against the spread of flame on a roof.

Fiber glass shingles are built on a core, or mat, of fiber glass reinforcement. Asphalt coating is applied directly to this mat, and protective, colored granules are embedded into the coating. Since the mat does not need to be saturated with asphalt, fiber glass shingles are lighter in weight than organic shingles and are more resistant to heat and humidity. Perhaps the most important factor that influences the quality of fiber glass shingle performance is the quality of the mat used in the construction of the shingle. Throughout the roofing industry, the quality of fiber glass mats varies widely. The best measurement of fiber glass shingle performance is ASTM D3462, a standard established by the American Society for Testing and Materials specifically for fiber glass shingles.

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