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 i