Roofing Terms

The following is a list of roofing terms to help you have a better knowledge about your roof and roofing materials. This however is not a complete listing of all roofing terms. Therefore, do not hesitate to ask your roofing supplier or contractor to explain to you any thing that you do not fully understand.

Base flashing: Flashing attached to the deck to direct the flow of water onto the roof surface.

Bundle: A package of shingles.

Butt edge: The lower exposed edge of a shingle.

Caulk: To make watertight by filling in a joint with mastic or asphalt cement.

Chalk line: A line used for aliment. It is made by snapping a taut string or cord dusted with chalk.

Class "A": Indicates that the roofing material is able to withstand severe exposure to fire originating from outside the building, such as with a brushfire.

Class "B": Indicates that the roofing material is able to withstand moderate exposure to fire that has originated outside the building.

Class "C": Indicates that the roofing material is able to withstand light exposure to fire that has originated outside the building.

Collar: Pre-formed flange placed over a vent pipe and used to seal the roof around the vent pipe opening.

Counter flashing: Flashing attached to a vertical surface.

Course: A row of shingles running the length of the roof.

Coverage: Amount of weather protection provided by the roofing material.

Cricket: A peaked saddle construction that is placed at the back of a chimney to deflect water away from the chimney, it is also used to prevent the accumulation of snow.

Deck: Plywood or oriented-strand board (OSB) sheathing to which the roofing is applied.

Dormer: A framed window that projects through the sloping plane of a roof.

Downspout: A pipe for draining water from the gutters.

Drip edge: A non-corrosive, non-staining material used along the eaves and rakes to ensure that water will run-off and drip clear of underlying construction.

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

Exposure-- The part of a shingle that is exposed to the weather.

Felt: Roofing material saturated with asphalt and used as an underlayment that creates a secondary, watertight barrier between the roofing products and the roof deck.

Gable: The upper portion of a sidewall, which forms a triangular point at the ridge of a sloping roof.

Gable roof: Contains a gable at each end.

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, which runs from the ridge to the eaves.

Hip roof: A type of roof containing sloping planes with the same pitch on all four sides, but does not contain any gables.

Hip shingles: Shingles used to cover the inclined external angle formed by the intersection of two sloping roof planes.

Ice: dam: Forms at the lower roof edge and is created by the thawing and re-freezing of melted snow on the overhang. Ice-dams can force water up and under shingles, causing leaks.

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

Pitch: The slope of a roof as expressed as the ratio of a roof's rise (vertical distance) to each foot of run (horizontal distance). A 3/12 pitch means the roof rises 3 inches for every 12 inches of horizontal distance.

Rafter: The framework that supports the roof deck and roofing, sloping from the ridge to the wall plate.

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

Ridge: The uppermost, peak where two sloped roof sections meet.

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

Roll roofing: an Asphalt roofing product that is manufactured in roll form.

Run: The horizontal distance of the roof. One half the span.

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

Soffit: The finished underside of the eaves.

Soil stack: A vent pipe that penetrates the roof.

Span: The horizontal distance from eaves to eaves.

Specialty eaves flashing membrane: A self-adhering, waterproofing shingle underlayment, which is used to protect against water infiltration due to ice dams or wind driven rain.

Square: A unit of roof measure that equals 100 square feet (an area 10' by 10').

Telegraphing: Distortions that are seen through a new roof, which are originally seen on the old roofing surface, this is seen when new shingles are applied over old or existing shingles.

Underlayment: 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.

Valley: The angle formed where two sloping roof surfaces intersect to provide water runoff.

Vent: Any device installed on the roof, gable, or soffit as an outlet for air.

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