When a material accepts quantities of gases or liquid, such as moisture.

Algae Discoloration

Roof discoloration that can be caused by algae. Commonly described incorrectly as fungus growth.

Angled Fasteners

Roofing nails and staples driven into decks at angles not parallel to the deck to fit into tons of tight spaces without running the nailer’s handle into a...


The Asphalt Roofing Manufacturers Association, a trade association upholding standards for North American manufacturers of asphalt roofing.