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. 


Asphalt Roofing Manufacturers Association. Organization of roofing manufacturers. 


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.


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. 


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. 


When shingles are subjected to high winds, and are forced off a roof deck. 


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.  


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


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.


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


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. 


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.


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


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


Nails or staples used to secure roofing to the deck.


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 


Materials used to waterproof a roof around any projections 

Flashing Cement

Sealant designed