Roofing Glossary


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.


APA - American Plywood Association. Test and sets standards for all varieties of

of plywood used in the U.S.


Apron flashing - Metal flashing used at chimney fronts.


ARMA - Asphalt Roofing Manufacturer's 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 or bull.


ASTM - The American Society for Testing and Materials. Organization that sets standards for a wide variety of materials, including roofing.



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.


Cobra® - GAFMC's respected brand name for ventilation products.


Corrosion - When rust, rot or age negatively affect roofing metals.


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


Crickets - a peaked water diverter installed behind chimney and other large roof projections. Effectivley diverts water around projections.


Cupping - When shingles are improperly installed over an existing roof or are overexposed, they form a curl or cup.



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



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 a top surface on shingles.



Ice Dam - When a snow load melts on roof and re-freezes at the eave areas. Ice dams force water to "back-up" a roof and cause leakage.



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.



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.


Over-driven - A term used for fasteners driven trough roofing material with too much force, breaking the material.


Over-exposed - Installing shingles courses higher than their intended exposure.



Quater sized - Term for the size of hand sealant dabs, size of a U.S. 25¢ piece.



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 in rolled roofing. Area without granules. Designed for nail placement and sealant.


Shed roof - Roof design of a single roos 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 from main roof material.


Steep slope roofing - Generally all slopes higher than 4/12 are concidered steep slopes.


Step-flashing - Metal flashing pieces at side-walls and chimneys for weather-proofing.



Under-driven - Term used to describe a fastener not fully driven flush to the shingle surface.


Underlayments - Asphalt based rooled materials designed to be installed under main roofing material, to serve as added protection.


Back-surfacing - Granular material added to shingle's back to assist in keeping seperation during delivery and storage.


Blistering - Bubbles or pimples in roofing materials. Usually moisture related. In shingles blisters are either moister unger the material or moister trapped inside the material.


Blow-offs - When shingles are subject to high winds, and are forced off a roof deck.


Buckling - When a wrinkle or ripple affects shingles or their underlayments.



Deck - The substate over wich roofingis applied. Usually plywood, wood boards, or planks.


Dormer - A rasised roof extending out of a larger roof plane.


Drip-edge - An installed lip that keeps shingles off the deck at edges, and extends shingles out over eaves and gutters, and prevents water from backing up under shingles.



Fasteners - Nails or staples used in securing roofing to the deck.


Felt - Organic or paper-based rolled material saturated with asphalt to serve as roofing underlayment.


FHA - The Federal Housing Authority. Sets construction standards throughout the U.S.


Fiberglass mat - Fibers condensed into strong, resilientmats 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 through the roof deck


Flashing cement - Sealant designed for use around flashing areas, typically than plastic cement.



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.



"L" flashing - Continuous metal flashing consisting of several feet of metal. Used at horizontal walls, bent to resemble an "L".


Laps - The area where roll roofing or rolled underlayment overlap one another durring application (see also side laps and end laps).


Low slopes - Roof pitches less than 4/12 are concidered low sloped roof. Special installation practices must be used on roofs sloped 2/12-4/12.



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.



Pitch - Ratio of the rise of the roof to the span of the roof.


Power vents - Electrically powered fans used to move air from attics and structures.


Plastic cement - Asphalt based sealant. Also called bull mastic, tar, asphalt cement.


Plumbing vents - Term used to describe plumbing pipes that project through a roof plane. Also called vent stacks.


Prevailing wing - The most common direction of wind for a particular region.



Racking - Method of installing shingles in a straight up the roof manner.


Rake edge - The vertical edge of gable style roof planes.


Ridge vent - Hard plastic vent that runs the ridge. It replaces the old style roof louvers.


Roof louvers - Rooftop rectangular shaped roof vents. Also called box vents, mushroom vents, airhawks, soldier vents.


Roof plane - A roofing are defined by havingfour seperate edges. One side of a gable, hip or mansard roof.



Tab - The bottom portion of traditional shingle seperated 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. Shingles installed over buckled shingles ma show some buckles.


Transitions - When a roof plane ties into another roof plane that has a different pitch or slope.



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.


Ventilation - The term used in roofing for the passege of air from an enclosed space.



Warm wall - The finished wall inside of a structure, used in roofing to determine how to install waterproof underlayments at eaves.


Waterproof underlayments - Modified bitumen based roofing underlayments. Designed to seal 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.