Roofing Glossary

Roofing Glossary & Terminology

3-tab shingle: An asphalt shingle consists of a single layer with the exposed area separated by cut-outs into three tabs that are approximately 12 to 13 inches.

Architectural shingle: An asphalt shingle made up of multiple layers. The tabs on these shingles are cut to different sizes and shapes to give the roof a more three-dimensional appearance. Also called dimensional or laminated shingles.

Asphalt shingle: A shingle created by covering a fiberglass mat with an asphalt-based coating, then adding mineral granules to the surface. One of the most common residential roofing materials, it is known for its durability and ease of installation.

Cool roof shingle: Shingles that are specially designed to remain at lower temperatures than traditional, non-reflective shingles when exposed to the sun’s rays, which may reduce attic temperature and help save on cooling costs.*

Cricket: A device that helps divert water around or away from chimneys and other large roof projections.

Designer shingle: Asphalt roofing shingles with highest-end multidimensional designs made to appear similar to slate or wood shake shingles. Often called a “premium” or “luxury” shingles.

Dimensional shingle: Another name for an architectural shingle.

Drip edge: Rigid material that is installed at the edge of the roof to keep shingles off the deck, extending them out over eaves and gutters. This helps control the direction of dripping water that could damage underlying components.

Flashing: A material installed around a roof penetration or along an edge to help keep moisture from seeping into the layers below. Can be found along the roof’s perimeter or at penetrations, walls, expansion joints, valleys, drains, and other places where the roofing is interrupted or terminated.

Laminate shingle: Another name for an architectural shingle.

Ridge cap shingles: Material specifically made to cover the peak ridge or hips of the roof.

Roof deck protection: Also known as underlayment, these GAF products are often synthetic or fiberglass-reinforced felts. They provide a water-shedding secondary layer of protection under the final roof covering.

Roof ridge vent: An air slot cut into the roof deck at the highest point on the roof. The vent construction protects the inside from the weather while allowing air to flow freely through the attic.

Roofing felt: A material laid down on top of the roof decking to protect the structure underneath. Typically made of asphalt-saturated paper or synthetic materials. Similar to underlayment.

Roofing underlayment: Asphaltic saturated organic or synthetic-based rolled materials designed to be installed under the main roofing materials to help shed water and resist weather infiltration. Sometimes referred to as felt.

Shingle: A small piece of roofing material designed to be installed in overlapping rows or courses.

Slope: The steepness of the roof expressed as a ratio. For example, a 4:12 slope means there are 4″ of vertical rise for every 12″ of horizontal length.

Solar panels: Racked solar panels (aka modules), which are separate from and on top of your roof, with the panels attached by dozens of roof penetrations

Solar roofing: A roofing system in which the solar is integrated into your home’s roof materials. See GAF Energy and this glossary of solar terms for more information.

Square: A measurement of roof area equal to 100 square feet or enough roofing material to cover 100 square feet of a roof deck.

Starter strip: The first row of roofing that is installed at the edge of the eave. They are also installed along the rakes to improve the wind resistance of the roof.

Tab: The bottom portion of a shingle, where the material is separated by the shingle cut-outs.

Valley: The place where two downward-sloping sections of a roof join, creating a “V” shaped depression.

Vapor retarder: A material used to impede the passage or movement of water vapor. Usually included as a layer during roofing installation.

Building Components

Attic vent: An opening that allows air, heat, and water vapor to escape from the attic. This helps prevent damage to roofing materials caused by overheating.

Decking: The structural material over which roofing is applied. Usually plywood, boards, or planks.

Dormer: A small, raised roof area protruding from the roof plane, usually housing a window.

Eave: The edge of a roof that overhangs the wall.

Fascia: The wood trim around the perimeter of a building, just under the roofing. Often nailed to the ends of trusses or rafters and used to hang gutters.

Gable roof: A traditional roof style in which two roof planes meet at the ridge line.

Hip roof: A roof with four roof planes coming together at a peak and four separate hip legs.

Sheathing: The structural material over which roofing is applied. Usually plywood, boards, or planks.

Soffit: The exposed area under a roof eave or overhang.

Vent: An opening that allows air, heat, and water vapor from inside a building to escape to the outside.

Other Roofing Terms

Asphalt: A bituminous waterproofing material applied to roofing materials during manufacture.

Blisters: Bubbles that may appear on the surface of asphalt roofing after installation.

Butt edge: The lower edge of the shingle tabs.

Dormer: A framed window unit projecting through the sloping plane of a roof.

Downspout: A pipe for draining water from roof gutters. Also called a leader.

Drip Edge: A corrosion-resistant, non-staining material used along the eaves and rakes to allow water run-off to drip clear of underlying construction.

Eave: The horizontal, lower edge of a sloped roof.

Eave Flashing: Additional layer of roofing material applied at the eaves to help prevent damage from water back-up.

Flashing: Pieces of metal used to prevent seepage of water into a building around any intersection or projection in a roof such as vent pipes, chimneys, adjoining walls, dormers and valleys. Galvanized metal flashing should be minimum 26-gauge.

Gable: The upper triangular portion of a sidewall that comes to a point at the ridge of a double sloping roof. 

Gable Roof: A simple two-sided roof above a gable.

Granules: Typically ceramic-coated colored crushed rock that is applied to the exposed surface of asphalt roofing products.

Gutter: The trough that channels water from the eaves to the downspouts.

Hip: The inclined external angle formed by the intersection of two sloping roof planes. Runs from the ridge to the eaves.

Hip Roof: A type of roof containing sloping planes on each of four sides. Contains no gables.

Ice Dam: Condition formed at the lower roof edge by the thawing and refreezing of melted snow on the overhang. Can force ponded water up and under shingles, causing leaks.

Ice Dam Protection: One or more courses of self-adhering underlayment installed at the eaves of a building to prevent damage from water back-up due to an ice dam. Also known as “Eave Flashing”.

Laminated Shingles: Shingles containing more than one layer to create extra thickness. Also called three-dimensional shingles or architectural shingles.

Overhang: That portion of the roof structure that extends beyond the exterior walls of a building.

Rafter: The supporting framing member immediately beneath the deck, sloping from the ridge to the wall plate.

Rake: The inclined edge of a sloped roof over a wall. 

Reroofing: The process of removing existing roof coverings and replacing them with a new roofing system.

Ridge: The uppermost, horizontal external angle formed by the intersection of two sloping roof planes.

Rise: The vertical distance from the eaves line to the ridge.

Roofing Tape: An asphalt-saturated tape used with asphalt cements for flashing and patching asphalt roofing.

Run: The horizontal distance from the eaves to a point directly under the ridge. One half the span.

Single Coverage: Asphalt roofing that provides one layer of roofing material over the deck.

Slope: The degree of roof incline expressed as the ratio of the rise, in inches, to the run, in inches. For example, the roof slope of 4/12 has a 4 inch rise every 12 inches.

Smooth-Surfaced Roofing: Roll roofing that is covered with ground talc or mica instead of granules (coated).

Soffit: The finished underside of the eaves.

Soil Stack: A vent pipe that penetrates the roof.

Span: The horizontal distance from eave to eave.

Square: A unit of roof measure covering 100 square feet.

Square-Tab Shingles: Shingles on which tabs are all the same size and exposure.

Starter Strip: Asphalt roofing applied at the eave that provides protection by an additional layer of material under the cutouts and joints of the first course of shingles.

Step Flashing: Base flashing application method used where a vertical surface meets a sloping roof plane.

Strip Shingles: Asphalt shingles made from a single layer that are approximately three times as long as they are wide.

Tear Off: To remove an existing roofing system down to the structural deck.

Underlayment: Asphalt saturated felt or specially engineered synthetic material used beneath roofing to provide additional protection for the deck.

Valley: The internal angle formed by the intersection of two sloping roof planes. 

Vent: Any outlet for air that protrudes through the roof deck such as a pipe or stack. Any device installed on the roof, gable or soffit for the purpose of ventilating the underside of the roof deck.