Professional Roofing Glossary of Terms

A type of roof discoloration caused by algae. Commonly called fungus growth.

A bituminous waterproofing agent applied to roofing materials during manufacturing.

Asphalt-based cement used to bond roofing materials. Also known as flashing cement or mastic; should conform to ASTM D-458

American Society for Testing and Materials. A voluntary organization concerned with development of consensus standards, testing procedures and specifications.

That portion of the flashing attached to or resting on the deck to direct the flow of water onto the roof covering.

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

package of shingles. There are 3, 4 or 5 bundles per square.

The lower edge of the shingle tabs.

To fill a joint with mastic or asphalt cement to prevent leaks.

A line made on the roof by snapping a taut string or cord dusted with chalk. Used for alignment purposes.

The highest fire-resistance rating for roofing as per ASTM E-108. Indicates roofing is able to withstand severe exposure to fire originating from sources outside the building.

Fire-resistance rating that indicates roofing materials are able to withstand moderate exposure to fire originating from sources outside the building.

Fire-resistance rating that indicates roofing materials are able to withstand light exposure to fire originating from sources outside the building.

A method of valley treatment in which shingles from one side of the valley extend across the valley while shingles from the other side are trimmed two inches from the valley centerline. The valley flashing is not exposed.

A layer of viscous asphalt applied to the base material into which granules or other surfacing is embedded.

Pre-formed flange placed over a vent pipe to seal the roof around the vent pipe opening. Also called a vent sleeve.

The change of water from vapor to liquid when warm, moisture-laden air comes in contact with a cold surface.

That portion of the flashing attached to a vertical surface to prevent water from migrating behind the base flashing.

row of shingles or roll roofing running the length of the roof.

A peaked saddle construction at the back of a chimney to prevent accumulation of snow and ice and to deflect water around the chimney.

The surface installed over the supporting framing members to which the roofing is applied.

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

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

A non-corrosive, non-staining material used along the eaves and rakes to allow water run-off to drip clear of underlying construction.

The horizontal, lower edge of a sloped roof.

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

Boards nailed along eaves and rakes after cutting back existing wood shingles to provide secure edges for reroofing with asphalt shingles.

Fibrous material saturated with asphalt and used as an underlayment or sheathing paper.

An asphalt roofing base material manufactured from glass fibers.

Pieces of metal or roll roofing 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.

Factory Mutual Research Corp.

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

A type of roof containing sloping planes of the same pitch on each side of the ridge. Contains a gable at each end.

A type of roof containing two sloping planes of different pitch on each side of the ridge. The lower plane has a steeper slope than the upper. Contains a gable at each end.

Ceramic-coated colored crushed rock that is applied to the exposed surface of asphalt roofing products.

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

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

A type of roof containing sloping planes of the same pitch on each of four sides. Contains no gables.

Condition formed at the lower roof edge by the thawing and re-freezing of melted snow on the overhang. Can force water up and under shingles, causing leaks.

Strip shingles containing more than one layer of tabs to create extra thickness. Also called three-dimensional shingles.

Method of installing asphalt shingles on roof slopes between two and four inches per foot.

A type of roof containing two sloping planes of different pitch on each of four sides. The lower plane has a much steeper pitch than the upper, often approaching vertical. Contains no gables.

Finely ground limestone, slate, traprock or other inert materials added to asphalt coatings for durability and increased resistance to fire and weathering.

Method of valley construction in which shingles on both sides of the valley are trimmed along a chalk line snapped on each side of the valley. Shingles do not extend across the valley. Valley flashing is exposed.

An asphalt roofing base material manufactured from cellulose fibers.

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

The degree of roof incline expressed as the ratio of the rise, in feet, to the span, in feet.

A compound used to seal flashings and in some cases to seal down shingles as well as for other small waterproofing jobs. Where plastic cement is required for sealing down shingles, use a dab about the size of a quarter unless otherwise specified.

Asphalt-based cement used to adhere tabs of strip shingles to the course below. Also used to adhere roll roofing laps applied by the concealed nail method.

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

The inclined edge of a sloped roof over a wall from the eave to the ridge.

A plastic or paper strip that is applied to the back of self-sealing shingles. This strip prevents the shingles from sticking together in the bundles, and need not be removed for application.

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

The vertical distance from the eaves line to the ridge.

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

Asphalt used to impregnate an organic felt base material.

An asphalt-impregnated felt used as an underlayment between the deck and the roofing material.

A thermal-sealing tab cement built into the shingle to firmly cement the shingles together automatically after they have been applied properly and exposed to warm sun temperatures. In warm seasons, the seal will be complete in a matter of days. In colder seasons, sealing time depends on the temperature and amount of direct sunlight hitting the shingles. Hand sealing with plastic cement should be done to ensure sealing in winter.

Shingles containing factory-applied strips or spots of self-sealing adhesive.

Factory-applied adhesive that bonds shingle courses together when exposed to the heat of the sun after application.

Slight differences in shingle color that may occur as a result of normal manufacturing operations.

Exterior grade boards used as a roof deck material.

A roof containing only one sloping plane. Has no hips, ridges, valleys or gables.

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

The degree of roof incline expressed as the ratio of the rise, in inches, to the run, in feet.

The finished underside of the eaves.

A vent pipe that penetrates the roof.

The horizontal distance from eaves to eaves.

A self-adhering, waterproofing shingle underlayment designed to protect against water infiltration due to ice dams or wind driven rain.

A unit of roof measure covering 100 square feet.

Asphalt roofing applied at the eaves that provides protection by filling in the spaces under the cutouts and joints of the first course of shingles.

Method of installing asphalt shingles on roof slopes greater than 21 inches per foot.

Flashing application method used where a vertical surface meets a sloping roof plane.

A shingle distortion that may arise when a new roof is applied over an uneven surface.

See laminated shingles.

The most popular type of asphalt shingle usually 12" x 36" in size with three tabs.

Underwriters Laboratories, Inc.

Label displayed on packaging to indicate the level of fire and/or wind resistance of asphalt roofing.

A layer of asphalt saturated (sometimes referred to as tar paper) which is laid down on a bare deck before shingles are installed to provide additional protection for the deck.

The internal angle formed by the intersection of two sloping roof planes to provide water runoff.

Any material used to prevent the passage of water vapor.

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.

Method of valley construction in which shingles from both sides of the valley extend across the valley and are woven together by overlapping alternate courses as they are applied. The valley flashing is not exposed.