Knowledgeable Roofing Company Serving Residential & Commercial Clients Since 2008

Being able to effectively communicate with your roofing company can help your roofing project go as seamlessly as possible. We know how daunting the whole roofing process can seem, especially if you know nothing about roofs or the materials used. That’s why Kerrigan Roofing and Restoration has come up with a glossary of common roofing terms that you can use throughout your project to stay in the loop with your contractor.

• Algae – Rooftop fungus that leaves dark staining on your roof
• Angled Fasteners – Roofing nails & staples driven into decks at angles not parallel to the deck
• Apron Flashing – Metal flashing used at chimney fronts
• ARMA – Asphalt Roofing Manufacturers Association, an 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 & metal for asphalt sealant
• Asphalt Plastic Cement – Asphalt-based material used to seal & adhere roofing materials, meeting ASTM D4586 Type I or II. It’s also called mastic, blackjack, roof tar and bull.
• ASTM – American Society for Testing and Materials, an organization that sets standards for a wide variety of materials, including roofing
• Back Surfacing – Granular material added to shingle’s back to keep shingles separated during delivery & storage
• Blistering – Bubbles or pimples in roofing materials, which are usually moisture related. In shingles, blisters are caused by either moisture under the material or moisture trapped inside the material.
• Blow-Offs – When shingles are subjected to high winds & are forced off a roof deck
• Buckling – When a wrinkle or ripple effects shingles or their underlayment
• 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.
• Cobra® – GAF’s respected brand name for ventilation products
• Counter Flashing – The metal or siding material that’s installed over roof-top base flashing systems
• Country Mansion® – GAF’s limited lifetime warranty shingle
• Crickets – A peaked water diverter installed behind chimneys & other large roof projections to effectively divert water 
• Cupping – When shingles are improperly installed over an existing roof or are over-exposed, they may form a curl or cup. This may also be due to a manufacturing defect.
• Deck – The substrate over which roofing is applied. It’s usually plywood, wood boards or planks.
• Deck Armor™ – Premium breathable roof deck protection. It provides a critical extra layer of protection between your shingles & your roof deck to help prevent wind-driven rain or water from other sources from infiltrating under your shingles and causing damage to your roof structure or to the inside of your home.
• Dormer – 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
• 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, this is the area where a roll ends on a roof and is overlapped by the next section of rolled material
• EWA – Engineered Wood Association, which tests and sets standards for all varieties of plywood used in the United States
• Exposure – The area on any roofing material that is left exposed to the elements
• Fasteners – Nails or staples used to secure roofing to the deck
• FHA – The Federal Housing Authority, which sets construction standards throughout the United States
• 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 & plumbing vents
• Flashing – Materials used to waterproof a roof around any projections
• Flashing Cement – Sealant designed for use around flashing areas. It’s typically thicker than plastic cement.
• Gable Roof – Traditional roof style with two peaked roof planes meeting at a ridge line of equal size
• GAF Cant – GAF cant strips that deflect water away from flashing areas. Typically used on low-slope roofs.
• Golden Pledge® – GAF’s strongest limited warranty for shingles & America’s strongest steep-slope warranty
• Grand Sequoia® – GAF shingle with wood shake appearance
• Grand Slate™ – GAF shingle with slate appearance
• Granules – Crushed rock that is coated with ceramic, fired and used as a 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” under shingles and cause leakage.
• “L” Flashing – Continuous metal flashing consisting of several feet of metal. Used at horizontal walls and bent to resemble an “L”.
• Laminated Shingles – Shingles made from two separate pieces that are laminated together, such as GAF Timberline® Series, Country Mansion® and Grand Sequoia® Shingles. Also called dimensional shingles and architectural shingles.
• Laps – The area where roll roofing or rolled underlayment overlap one another during application (see also side laps and end laps)
• Liberty™ – Self-adhering low-slope roofing. Liberty™ systems are applied without torches, open flames, hot asphalt or messy solvent-based adhesives.
• 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. Shingles cannot be installed on slopes less than 2/12.
• 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 & certain rolled products
• Modified bitumen – Rolled roofing membrane with polymer modified asphalt & either polyester or fiberglass reinforcement
• Mortar – Mixture of sand, mortar, limestone & water used in bonding a chimney’s bricks together
• Nail Guide Line – Painted line on laminated shingles that aids 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 and aligning courses with the original roof to avoid shingle cupping
• NRCA – The National Roofing Contractors Association, a respected national organization of roofing contractors
• Open Valley – Valley installation using metal down the valley center
• Organic Mat – Material made from recycled wood pulp & paper
• Organic Shingles – Shingles made from organic (paper) mats
• OSB – Oriented Strand Board, a decking made from wood chips & lamination glues
• Overdriven – The term used for fasteners driven through roofing material with too much force, breaking the material
• Overexposed – Installing shingle courses higher than their intended exposure
• Quarter Sized – Term for the size of hand sealant dabs, size of a 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 WeatherWatch® & StormGuard® underlayment. Used for packaging & handling, it must be removed before installation.
• Rigid Vent – Hard plastic ridge vent material
• Roof Louvers – Rooftop rectangular-shaped roof vents. Also called box vents, mushroom vents, airhawks and 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. Also called dragon teeth, they’re shaped to imitate the wood shake look on a roof.
• Self-Sealant – Sealant installed on shingles. After installation, heat & sun will activate sealant to seal the shingles to one another.
• Selvage – The non-exposed area on rolled roofing. It’s an area without granules that’s designed for nail placement & sealant.
• Shed Roof – Roof design of a single roof plane. Area does not tie into any other roofs.
• Shingle-Mate® – GAF’s shingle underlayment. It’s a breather type with fiberglass backing to reduce wrinkles & 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
• GAF Shingle & Accessory Ltd. Warranty – GAF’s standard shingle limited warranty
• 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
• Stepflashing – Metal flashing pieces installed at sidewalls and chimneys for weatherproofing
• StormGuard® – GAF waterproof underlayment. It’s a film-surfaced rolled underlayment with 1.5 squares of coverage per roll.
• Tab – The bottom portion of a 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. For example, shingles installed over buckled shingles may show some buckles.
• Timberline® Series – GAF’s trademark name for laminated wood-shake style shingles
• TimberTex® – GAF enhanced Hip and Ridge Shingles
• Transitions – When a roof plane ties into another roof plane that has a different pitch or slope
• Underdriven – Term used to describe a fastener not fully driven flush to the shingle’s surface
• Underlayments – Asphalt-based rolled materials designed to be installed under main roofing material as added protection
• Valleys – Area where two adjoining sloped roof planes intersect on a roof to create a V-shaped depression
• Vapor – Term used to describe moisture-laden air
• Warm Wall – The finished wall inside of a structure. Used in roofing to determine how far up the deck 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 that are designed to seal wood decks & waterproof critical leak areas
• Weather Stopper® Integrated Low-Slope Roofing System™ – GAF’s complete roofing system & components
• Weather Stopper System Plus Ltd. Warranty Plus Limited Warranty – GAF’s next grade of enhanced warranty that offers extended coverage for owners
• WeatherWatch® – GAF’s granule-surfaced waterproof underlayment
• Woven Valleys – The method of installing valleys by laying one shingle over the other up the valley center