Roofing Terminology

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.

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.

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  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).

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  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 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.

Stepflashing 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.

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.

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