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.