Roofing Terminology



Deck: A structural component of the roof. The deck supports the design, dead, and live loads, including the weight of the roof system, and additional live loads (ie. snow etc.) as set forth (required by) in building codes. The deck also provides the substrate to which the roofing or waterproofing system is applied to the structural surface of a building. Decks can be non combustible, metal, concrete, gypsum, or combustible, wood, plywood, osb etc.

Dormer: Pop up from the main roofline, like a small house with its own walls, roof, and window. Roof dormers provide light, added space, and ventilation to the topmost spaces in the house.

Eave: The lower part of a roof that overhangs the walls.

Flashing: Sheet metal used in waterproofing roof valleys or hips or the angle between a chimney and a roof.

Gable: Triangular end of a building from cornice or eaves to ridge.

Hip: The external angle formed by the meeting of two sloping sides of a roof that have their wall plates running in different directions.

Rake: The pitched edge of a gable roof. Rakes may be close, or extend from the building to allow for an overhang.

Ridge: The line of intersection at the top between the opposite slopes or sides of a roof.

Roofing Square: A 10' x 10' area that equals 100 sq. ft.

Underlayment: An asphalt saturated felt, or other sheet type material installed between the roof deck and other roofing materials. Underlayments are also a second line of defense in shedding water on steep sloped roofs.

Valley: A change in roof direction, where two planes meet at the bottom of their pitch to make a valley with two steep slopes running up and away from it.

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.