Fibreglass Shingle

A fibreglass shingle (US spelling: fiberglass) is an asphalt shingle whose reinforcing core is a non-woven mat of glass fibres bonded with resin, usually urea-formaldehyde. The mat is coated with asphalt that contains powdered mineral filler, then surfaced with granules. Almost all asphalt shingles made today are of this type.

History

Glass-fibre mats were introduced in 1960 with limited success at first. Improvements in mat and coating technology followed, and by about 1982 fibreglass shingles had overtaken organic-felt shingles in the United States. By 2011 organic shingles had disappeared from North American production.

Properties

• Lighter: the glass mat needs less asphalt, so area weights are typically about 1.8-2.3 lb/sq ft (8.8-11.2 kg/m²).
• Fire resistance: glass-mat shingles can achieve a Class A fire rating under ASTM E108 / UL 790, the highest class.
• Moisture: the glass mat does not absorb water, so the shingle is less prone to rot-related curling.
• Brittleness: early products could crack in cold weather or during handling; polymer-modified asphalts were later introduced to improve flexibility.

Standards

In the United States, ASTM D3462 is the main product standard for glass-felt asphalt shingles surfaced with mineral granules, and the International Building Code requires asphalt shingles to comply with it. The standard sets a minimum Elmendorf tear strength of 1,700 g. In Canada, CSA standards apply, and in Europe glass-fibre bitumen shingles are covered by the European harmonised standard for bitumen shingles.

Quality

Weight alone is no longer a reliable sign of quality. Industry commentary notes that mat strength and coating quality vary between products, and a moderate-weight shingle with a strong mat can outperform a heavier one with a weak mat.