Glossary of Roofing Terms

-A-

APP Modified Torchdown Roofing - A high-quality bitumen material combined with polymeric resins and reinforced with polyester matting. Impermeable to rainwater and resistant to damaging UV rays. Approximate service life of up to 20 years.

Asphalt - a. A dark brown to black substance found in natural beds and is also obtained as a residue in petroleum or coal tar refining that consists chiefly of hydrocarbons. b. Asphaltic composition used for pavements and as a waterproof cement.

Attic - The open space between the underside of the roof sheathing and the upper side of the ceiling directly below the roof.

-B-

Base Flashing - a. That portion of the flashing that is attached to or rests on the roof deck to direct the flow of water on a roof, or to seal against the roof deck. b. A material applied to the base of a wall extending above the roofline, as protection for the junction of the vertical wall and the roof.

Bitumen - Bitumens are mixtures of hydrocarbons of natural or pyrogeneous origin; or combinations of both, frequently accompanied by their non-metallic derivatives, which may be gaseous, liquid, or solid, and which are completely soluble in carbon disulfide. In the roofing industry, the word covers both asphalt and coal tar pitch.

-C-

Cant Strip - A beveled support used at the junction of the roof deck with a vertical surface, so that bends in the roofing membrane to form base flashings can be made without damage to the membrane.

Caulk - A compound used to fill joints, gaps, and imperfections.

Closed Valley - A valley in which the flashing is covered by a shingle membrane.

Condensation - The change from water vapor to liquid water, resulting from a drop in temperature of an air vapor mixture.

Coping - The cap or highest covering course of a wall, usually overhanging the wall and having a sloping top to carry off water.

Counter Flashing - Strips of metal, roofing, or fabric inserted and securely anchored to the reglet or attached to a vertical surface above the plane of the roof, and turned down over the face flashing to protect the base flashing.

Course - A row of shingles that can run horizontally, diagonally or vertically.

Curb - A wall of wood or masonry built above the level of the roof, surrounding a roof opening for a skylight, roof fan, or other equipment.

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-D-

DeadLoad - The total weight of all installed materials and the constant weight of a roof used to compute the strength of all supporting framing members.

Deck - The top surface of a structure, serving as a substrate for the roofing membrane. Normally consists of plywood, boards, or other sheet materials such as oriented-strand board (OSB). Fastened with nails or screws.

Dormer - A separate smaller roofed structure that projects from a sloping roof to provide more space below the roof, usually containing a vertical window.

Downspout - A pipe conveying rainwater from a roof gutter to a drain.

Drip Edge - A modified L-shaped flashing used along the eaves and rakes. The drip edge directs runoff water away from the deck, fascia, eaves, and siding.

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-E-

Eave - The horizontal roof overhang that extends outward and is not directly over the exterior walls or the building interior. The horizontal lower edge of sloped roof.

Exposure - That portion of a shingle that is exposed to the weather.

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-F-

Fascia - A wood trim board used to hide the cut ends of the roof rafters and sheathing. The gutter system is usually nailed to the fascia.

Fire Rating - The Underwriters Laboratories (UL) system for classifying the fire-resistance of various materials. Roofing materials are classified as Class "A"," "B", or "C", with Class "A" materials having the highest resistance to fire originating outside the structure.

Fire-Resistant - Material that is resistant to ignition by fire.

Fire Wall - Any wall built for the purpose of restricting the spread of fire in a building. Such walls of solid masonry or concrete usually divide a building from the foundations to about a meter above the roof.

Flashing - Metal strips used to form a watertight seal between the items butted up against the shingles. Flashing is used along walls, chimneys and dormers. Metal is usually 28 gauge galvanized sheet metal, but may be lead, copper, tin or aluminum. Prevents the seepage of water around any intersection or projection in a roof, such as vent pipes, chimneys, valleys, and the joints at vertical walls.

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-G-

Gable - The triangular end of an exterior wall from the level of the eaves to the ridge of a double-sloped roof.

Gambrel Roof - A type of roof which has its slope broken by an obtuse angle, so that the lower slope is steeper that the upper slope. A double-sloped roof having two pitches.

Gravel Stop - A gravel guard used at the rakes and eaves of a built-up gravel coated roof.

Gutter - Through at the eaves of a roof to convey rainwater from the roof to downspout.

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-H-

Header - The beam into which the common joists are fitted when framing around a roof opening.

Head Lap - The overlapping of shingles or roofing felt at their top edge.

Hip Roof - A roof, which rises by inclined planes from all four sides of a building. The line where two adjacent sloping sides of a roof meet is called the hip.

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-I-

No terms defined.

-J-

No terms defined.

-K-

No terms defined.

-L-

Live Load - The total weight of all installed equipment and materials and all variable weight that will move across a surface.

-M-

Membrane - A waterproofing system or roof covering.

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