Glossary of Roofing Terms
- 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 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, 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 effects shingles or their underlayments.
- Closed-cut valley – A shingle valley installation method where one roof plane’s shingles completely cover the others. The top layer is cut to match the valley lines.
- Corrosion – When rust, rot, or age negatively effect roofing metals.
- Counter-flashing – The metal or siding material that is installed over roof-top base flashing systems.
- 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 the deck at the edges and extends out over eaves and gutters, and prevents water from backing up under shingles.
- 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 roofing underlayment.
- 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.
- 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. 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; the size of a U.S. $.25 coin.
- Racking – Method of installing shingles in a straight-up-the-roof manner.
- Rake edge – The vertical edge of gable style roof planes.
- 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.
- Self sealant – Sealant installed on shingles. After installation, heat from the 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.
- Side-laps – The area on rolled material where one roll overlaps the rolled material beneath it. Also called selvage 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 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 weatherproofing.
- 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.
- 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 shingle 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.
- Woven valleys – The method of installing valleys by laying one shingle over the other up the valley center.