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.

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

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.

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.

: 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.

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 underlayment overlap one another during application (see also side laps and end laps).

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.

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.

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.

: Metal flashing pieces installed at sidewalls and chimneys for weatherproofing.
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.

: 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.

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