Roofing Definitions and Glossary of Important Terms



Rooftop fungus that can  leave dark stains on roofing


Asphalt is a sticky, black and highly vicious liquid or semi-solid form of petroleum. It may be found in natural deposits or may be a refined product; it is a substance classed as a pitch.


Asphalt Roofing Manufacturers Association is an organization of asphalt roofing manufacturers.

Asphalt Primer

Asphalt-based primer used to prepare the surface of concrete, metal, or other materials to enhance the adhesion of asphalt adhesives or asphalt sealant.  Meets ASTM D41. 

Air Barrier

The assembly of materials used in building construction to reduce or slow the passage of air into and out of the building.

Angled Fasteners

Roofing nails and staples driven into decks at an angle – not perpendicular to the roof deck surface. 

APA: The Engineered Wood Association

The APA: The Engineered Wood Association is a trade organization that develops product standards, installation standards, and does certification testing of engineered wood products such as plywood and OSB (oriented strand board).

Asphalt Plastic Cement

A solvent-based asphalt sealant used for hand sealing shingles and sealing other locations on asphalt roofs.  Meets ASTM D4586 Type I or II.

Apron Flashing

Metal flashing used at chimney or dormer fronts.


ASTM International (formerly The American Society for Testing and Materials), an organization that develops and publishes voluntary consensus standards, test methods, and specifications for a wide variety of materials, including roofing.


Base Sheet

First layer or base ply in low-slope multi-ply roofing systems.


When shingles are subjected to high winds and are forced off a roof deck by the wind.


A visible wrinkle or ripple in shingles or underlayments.  

Butt Edge

The lower edge of the shingle or shingle tabs.

Back Surfacing

A material (normally a fine-mineral material) applied to the back of shingles or roll products to keep them from sticking together in the package during shipping, storage, and delivery.


Bubbles or pimples in roofing materials. Usually moisture related.


Camelot® Shingle

A GAF Designer shingle with oversized tabs and an ultra-dimensional profile.

Cap Sheet

Top or final layer on low-slope roof systems.

Cant Strips

A triangular strip of material typically used on low-slope roofs for deflecting water away from flashing areas. 

Cool Roof

A roof system that uses products with a top surface of highly-reflective and emissive material. Cool roof surfaces can remain at markedly lower temperatures when exposed to solar heat in service than surfaces of roofs constructed with traditional non-reflective roofing products. Timberline® Cool Series® is one example. 

Counter Flashing

The metal or siding material installed over rooftop base flashing systems.



A raised roof extending out of a larger roof plane.

Drip Edge

A non-corrosive metal lip that keeps shingles up off the deck at roof edges and extends shingles out over eaves and rakes that allows water to drip clear of underlying construction and to provide a finished look.

Dragon Teeth

The exposed section of double thickness on Timberline® Shingles – also called saw-teeth. Shaped to imitate a wood shake look on the roof.


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.


FeltBuster® Roof Deck Protection

Quality, synthetic roof deck protection to help prevent wind-driven rain from infiltrating under the roof’s shingles and potentially damaging the home’s structure and interior.

Fiberglass Mat

Glass fibers formed into strong, resilient mats for use in roofing materials. 


Federal Housing Authority.


The flat metal extending out on the roof from around flashing pieces, usually at chimneys and plumbing vents.


Components used to weatherproof or seal roof system edges at perimeters, penetrations, walls, expansion joints, valleys, drains, and other places where the roof covering is interrupted or terminated.

Flashing Cement

Sealant designed for use around flashing areas as a component in the flashing system, typically thicker than asphalt plastic cement.


A flexible sheet manufactured by the interlocking of fibers with a binder or through a combination of mechanical work, moisture, and/or heat.

Gable Roof

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

GAF Shingle & Accessory Ltd. Warranty

GAF standard shingle limited warranty that covers GAF asphalt shingles and GAF accessories.

Golden Pledge® Warranty

The strongest GAF limited warranty for shingles.

Grand Canyon® Shingles

Ultra-Premium Designer roofing shingle.  The ultimate choice for a rugged wood-shake look.

Grand Sequoia® Shingles

GAF value collection designer roofing shingle with a rugged wood-shake appearance.


Crushed rock that is colored with ceramic coating and used as the top surface of shingles and other roofing material.



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

Hip Legs

The down-slope ridges on hip roofs.

Hip & Ridge Cap Shingles

The final layer of the roof at the ridge or hip, used to ensure protection at the highest areas of the roof and to accentuate the natural beauty of the roof by adding dimension and depth. 

High Nailing

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