Roofing, Guttering & Soffit/Fascia Terms Algae — A type of fungus that can leave dark stains on a roof.Angled fasteners — An installation-related problem that occurs when the shaft of roofing nails or staples are driven into decks at angles that are not perpendicular to the roof's deck.Asphalt — A bituminous waterproofing agent used in various types of roofing materials.Blistering — Bubbles in roofing materials that are usually caused by a poorly insulated roof and are usually moisture-related.Blow-offs — When shingles are torn loose from their position on the roof by high winds. Shingles that are nearing the end of their normal life cycle are prone to blow-offs, as are shingles that have been improperly installed (i.e., angled, under-driven or over-driven fasteners or high nails and/or over-exposed shingles).Buckling — A wrinkle or ripple in the shingles or underlayment.