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.

Duble-Coverage Mineral Guard®- Roll roofing material with 19″ selvage edge for double coverage over roof deck.

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.

EWA- Engineered Wood Association. Tests and sets standards for all varieties of plywood used in the U.S. 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 Sequoia® 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.

Mats- The general term for the base material of shingles and certain rolled products.

Modified bitumen- Rolled roofing membrane with polymer modified asphalt and either polyester or fiberglass reinforcement.

Mortar- Mixture of sand, mortar, limestone and water used in bonding a chimney’s bricks together. Nail Guide Line- Painted line on laminated shingles, to aid in the proper placement of fasteners.

Nail-Pop- When a nail is not fully driven, it sits up off the roof deck. Nesting- Installing a second layer of shingles aligning courses with the original roof to avoid shingle cupping.

NRCA- The National Roofing Contractors Association. Respected national organization of roofing contractors.

Open Valley- Valley installation using metal down the valley center. Organic Mat- Material made from recycled wood pulp and paper.

Organic Shingles- Shingles made from organic (paper) mats.

OSB- Oriented Strand Board. A decking made from wood chips and lamination glues.

Overdriven- The term used for fasteners driven through roofing material with too much force, breaking the material. Overexposed- Installing shingle courses higher than their intended exposure.

Quarter Sized- Term for the size of hand sealant dabs, size of a U.S. 25¢ piece.

Racking- Method of installing shingles in a straight up the roof manner. Rake Edge- The vertical edge of gable style roof planes.

Release Film- The plastic sheet installed on the back of WeatherWatch® and StormGuard® underlayments. Used for packaging and handling. Remove before installation.

Rigid Vent- Hard plastic ridge vent material.

Roof Louvers- Rooftop rectangular shaped roof vents. Also called box vents, mushroom vents, airhawks, soldier vents.

Roof Plane- A roofing area defined by having four separate edges. One side of a gable, hip or mansard roof.

Sawteeth- The exposed section of double thickness on Timberline® Series shingles – also called dragon teeth. Shaped to imitate wood shake look on the roof.

Self-Sealant- Sealant installed on shingles. After installation, heat and sun will activate sealant to seal the shingles to each other.

Selvage- The non exposed area on rolled roofing. Area without granules. Designed for nail placement and sealant.

Shed Roof- Roof design of a single roof plane. Area does not tie into any other roofs.

Shingle-Mate®- GAF’s shingle underlayment. Breather type with fiberglass backing to reduce wrinkles and buckles.

Side Laps- The area on rolled material where one roll overlaps the rolled material beneath it. Also called selvage edge on rolled roofing.

Side Walls- Where a vertical roof plane meets a vertical wall. The sides of dormers etc.

Soffit Ventilation- Intake ventilation installed under the eaves, or at the roof edge.

GAF Shingle & Accessory Ltd. Warranty- GAF’s standard shingle limited warranty.Starter Strip- The first course of roofing installed. Usually trimmed from main roof material.

Steep-Slope Roofing- Generally all slopes higher than 4/12 are considered steep slopes.

Stepflashing- Metal flashing pieces installed at sidewalls and chimneys for weatherproofing.

StormGuard®- GAF waterproof underlayment. Film-surfaced rolled underlayment, 1.5 squares coverage per roll.

Tab- The bottom portion of traditional shingle separated by the shingle cut-outs.

Tear-Off- Removal of existing roofing materials down to the roof deck.

Telegraphing- When shingles reflect the uneven surface beneath them. Ex: Shingles installed over buckled shingles may show some buckles.

Timberline® Series- GAF’s trademark name for laminated wood-shake-style shingles.

TimberTex® – GAF enhanced Hip and Ridge Shingles.

Transitions- When a roof plane ties into another roof plane that has a different pitch or slope.

Underdriven- Term used to describe a fastener not fully driven flush to the shingles surface.Underlayments- Asphalt-based rolled materials designed to be installed under main roofing material to serve as added protection.

Valleys- Area where two adjoining sloped roof planes intersect on a roof creating a “V” shaped depression.

Vapor- Term used to describe moisture laden air.

Warm Wall- The finished wall inside of a structure, used in roofing to determine how far up the deck to install waterproof underlayments at eaves.

Warranty- The written promise to the owner of roofing materials for material related problems.

Waterproof Underlayments- Modified bitumen based roofing underlayments. Designed to seal to wood decks and waterproof critical leak areas.

Weather Stopper® Integrated Low-Slope Roofing System™- GAF’s complete roofing system and components.

Weather Stopper System Plus Ltd. WarrantyPlus Limited Warranty- GAF’s next grade of enhanced warranty. Extended coverage for owners.

WeatherWatch® – GAF’s granule-surfaced waterproof underlayment.

Woven Valleys- The method of installing valleys by laying one shingle over the other up the valley center.