Roofing Glossary

Algae: Rooftop fungus that can leave dark stains on roofing.

Angled Fasteners: Roofing nails and staples driven into decks at angles not parallel to the deck.

Apron Flashing: Metal flashing used at chimney fronts.

ARMA: Asphalt Roofing Manufacturers Association. Organization of roofing manufacturers.

Asphalt: A bituminous waterproofing agent used in various types of roofing materials.

Asphalt Concrete Primer: Asphalt based primer used to prepare concrete and metal for asphalt sealant.

Asphalt Plastic Cement: Asphalt based sealant material, meeting ASTM D4586 Type I or II. Used to seal and adhere roofing materials. Also called mastic, blackjack, roof tar, bull.

ASTM: The American Society for Testing and Materials. Organization that sets standards for a wide variety of materials, including roofing.

Back Surfacing: Granular material added to shingle’s back to assist in keeping separate during delivery and storage.

Blistering: Bubbles or pimples in roofing materials. Usually moisture related. In shingles blisters are caused by either moisture under the material or moisture trapped inside the material.

Blow-Offs: When shingles are subjected to high winds, and are forced off a roof deck.

Buckling: When a wrinkle or ripple affects shingles or their underlayments.

Closed Cut Valley: A shingle valley installation method where one roof plane’s shingles completely cover the other’s. The top layer is cut to match the valley lines.

Cobra®: GAF’s respected brand name for ventilation products.

Counter Flashing: The metal or siding material that is installed over roof-top base flashing systems.

Country Mansion®: GAF’s limited lifetime warranty shingle.

Crickets: A peaked water diverter installed behind chimneys and other large roof projections. Effectively diverts water around projections.

Cupping: When shingles are improperly installed over an existing roof or are over-exposed, they may form a curl or cup. May also be due to a manufacturing defect.

Deck: The substrate over which roofing is applied. Usually plywood, wood boards, or planks.

Deck Armor: Premium breathable roof deck protection. It provides a critical extra layer of protection between your shingles and your roof deck to help prevent wind-driven rain (or water from other sources) from infiltrating under your shingles and causing damage to your roof structure or to the inside of your home.

Dormer: A raised roof extending out of a larger roof plane.

Drip Edge: An installed lip that keeps shingles up off the deck at edges, and extends shingles out over eaves and gutters, and prevents

Eaves: The roof edge from the fascia to the structure’s outside wall. In general terms, the first three feet across a roof is termed the eave.

End Laps: When installing rolled products in roofing, the area where a roll ends on a roof, and is overlapped by the next section of rolled material.

Exposure: The area on any roofing material that is left exposed to the elements.

Fasteners: Nails or staples used to secure roofing to the deck.

FHA: The Federal Housing Authority sets construction standards throughout the U.S.

Fiberglass Mat: Fibers condensed into strong, resilient mats for use in roofing materials.

Flange: Metal pan extending up or down a roof slope around flashing pieces. Usually at chimneys and plumbing vents

Flashing: Materials used to waterproof a roof around any projections

Flashing Cement: Sealant designed for use around flashing areas, typically thicker than plastic cement.

Gable Roof: Traditional roof style; two peaked roof planes meeting at a ridge line of equal size.

GAFCant®: GAF cant strips for deflecting water away from flashing areas. Typically used on low slope roofs.

Golden Pledge®: GAF’s strongest limited warranty for shingles. America’s strongest steep slope warranty.

Grand Sequoia®: GAF shingle with wood shake appearance.

Grand Slate: GAF shingle with slate appearance.

Granules: Crushed rock that is coated with a ceramic coating and fired, used as top surface on shingles.

Hand-Sealing: The method to assure sealing of shingles on very steep slopes, in high wind areas, and when installing in cold weather.

High Nailing: When shingles are nailed or fastened above the manufacturer’s specified nail location.

Hip Legs: The down-slope ridges on hip roofs.

Hip Roof: A roof with four roof planes coming together at a peak and four separate hip legs.

Ice Dam: When a snow load melts on a roof and re-freezes at the eave areas. Ice dams force water to “back-up” under shingles and cause leakage.

“L” Flashing: Continuous metal flashing consisting of several feet of metal. Used at horizontal walls, bent to resemble an “L”.

Laminated Shingles: Shingles made from two separate pieces that are laminated together. Such as GAF Timberline® Series, Country Mansion® and Grand Sequoi® Shingles. Also called dimensional shingles and architectural shingles.

Laps: The area where roll roofing or rolled underlayments overlap one another during application (see also side laps and end laps).

Liberty: Self-adhering low slope roofing. Liberty systems are applied without torches, open flames, hot asphalt, or messy solvent-based adhesives.

Low Slopes: Roof pitches less than 4/12 are considered low sloped roofs. Special installation practices must be used on roofs sloped 2/12-4/12. Shingles can not be installed at slopes less than 2/12.

Mansard: A roof design with a nearly vertical roof plane that ties into a roof plane of less slope at its peak.