Below are a series of roofing terms that our Twin Cities area roofing customers may find helpful. Feel free to
email us any time if you have
any additional roofing questions.
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. Tests and sets standards for all varieties of plywoods 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, 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 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.
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 base flashing systems.
Country Mansion® & Country Estates™ - GAFMC's limited lifetime warranty shingle.
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 form a curl or cup.
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 of the deck at edges, and extends shingles out over eaves and gutters, and prevents water
from backing up under shingles.
Dubl-Coverage® Mineral Guard - Roll roofing material with 19" selvage edge for double coverage over roof deck.
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
(underlayments, rolled roofing).
Exposure - The area on any roofing material that is left exposed to the elements.
Fasteners - Nails or staples used in securing roofing to the deck. Felt-Organic or paper-based rolled material saturated with asphalt to serve as
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 through the roof deck.
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.
GAFCant® - GAFMC cant strips for deflecting water away from flashing areas. Typically used on low slope roofs.
Golden Pledge® - GAFMC's strongest limited warranty for shingles. America�s strongest steep slope warranty.
Grand Sequoia® - GAFMC shingle with wood shake appearance.
Grand Slate™ - GAFMC shingle with slate appearance.
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" a roof 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. GAFMC Timberline® Series, Country Mansion® and Grand Sequoia®
Shingles. 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.
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.
Over-driven - The term used for fasteners driven through roofing material with too much force, breaking the material.
Over-exposed - Installing shingle courses higher than their intended exposure.
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 wind - The most common direction of wind for a particular region.
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 Weather Watch® and StormGuard® 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 Timberline® Series shingles. 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.
Shingle-Mate® - GAFMC's shingle underlayment. Breather type with fiberglass backing to reduce wrinkles and buckles.
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.
Smart Choice® Limited Warranty - GAFMC's standard shingle limited warranty.
Smart Choice® System Plus Limited Warranty - GAFMC's next grade of enhanced warranty. Extended coverage for owners.
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.
Step-flashing - Metal flashing pieces installed at side-walls and chimneys for weather-proofing.
StormGuard® - GAFMC waterproof underlayment. Film surfaced rolled underlayment, 1.5 squares coverage per roll.
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. Shingles installed over buckled shingles may show some buckles.
Timberline® Series - GAFMC's trademark name for laminated wood shake style shingles.
TIMBERTEX® - GAFMC enhanced Hip and Ridge Shingles.
Transitions - When a roof plane ties into another roof plane that has a different pitch or slope.
Under-driven - 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.
Ventilation - The term used in roofing for the passage 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.
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.
Weather Stopper® Integrated Roofing System™ - GAFMC's complete roofing system and components.
Weather Watch® - GAFMC's granule surfaced waterproof underlayment.
Woven Valleys - The method of installing valleys by laying one shingle over the other up the valley center.