Asphalt Shingles Roofing

Shingles are judged by weight per square. Organic shingles contain around 40% more asphalt per square (100 sq. ft.) than fiberglass shingles which makes them weigh more and gives them excellent durability and blow-off resistance. Shingle durability is ranked by warrantied life, ranging from 20 years to 50 years and in some cases lifetime warranties are available.

Fiberglass shingles have a base layer of glass fiber reinforcing mat. The glass fiber mat is not waterproof by itself. Fiberglass mat is made from wet, random-laid fiberglass bonded with urea-formaldehyde resin. The mat is then coated with asphalt which contains mineral fillers and makes the fiberglass shingle waterproof. Fiberglass reinforcement was devised as the replacement for asbestos paper reinforcement of roofing shingles and typically ranges from 1.8 to 2.3 pounds per square foot. The older asbestos versions were very durable and hard to tear, an important property when considering wind uplift of shingles in heavy storms. Fiberglass has replaced mostly all versions in the United States. Widespread hurricane damage in Florida during the 1990s prompted the industry to adhere to a 1700 gram tear value on finished asphalt shingles. A newer design of fiberglass asphalt shingle, called laminated or architectural, uses two distinct layers which are bonded together with asphalt sealant.

Laminate shingles are heavier, more expensive, and arguably more durable than traditional 3-tab shingle designs. Laminated shingles also give a more varied, contoured visual effect to a roof surface. Per the 2003 International Building Code Sections 1507.2.1 and 1507.2.2, asphalt shingles shall only be used on roof slopes of two units vertical in 12 units horizontal (17-percent slope) or greater. Asphalt shingles shall be fastened to solidly sheathed decks.