Roof Terms & Definitions

If you’ve had a recent roof repair or replacement or you’ve recently met with a professional roofing company to install a new roof, you may have heard some terms you’re unfamiliar with. We’ve compiled a list of common roof terms and definitions so you won’t be confused when your roofing contractor discusses your roofing issues with you in the future.

Common roof terms you might hear include:

Aggregate – Stone, rock, water-worn gravel or slag (in a range of different sizes) used for UV protection; granule is an example

Apron flashing – flashing at the juncture of the top of a sloped roof and a vertical wall

Area Divider – raised, flashed assembly that extends above the roof’s surface when an expansion joint isn’t required or to separate large roof areas

Back surfacing – mineral matter that is applied to the back of shingles so they don’t stick

Ballast – different materials used to protect roofing from UV rays (see aggregate)

Base flashing – part of the flashing attached to (or resting on) the deck, which is used to direct the flow of water onto the roof covering

Blister – bubble that sometimes appears on the roof’s surface after installation or is caused by expansion of trapped air or water

Built-up roof (BUR) – flat roofing or low-sloped roofing that has multiple layers of asphalt and ply sheets

Cap sheet – granulated surface used as the top ply of a BUR; when used, aggregate isn’t required

Caulk – mastic or asphalt cement used to fill prevent small leaks in the flashing

Cladding – material used for the exterior wall of a building

Cornice – the top set of moldings below the roofline

Coverage – the amount of weather protection provided by your roofing material

Counterflashing – usually metal sheeting attached to a pipe, rooftop unit or other surface to protect the upper edge of the base flashing

Deck – surface (typically plywood) where materials are applied

Dormer – a structural element protruding from the surface of a sloped roof, creating more usable space inside the building or house

Dormer rafter – roof rafters that frame the dormer roof

Downspout – vertical pipe that carries water from the gutter to the ground

Drip edge – overhang (usually metal flashing) used to direct dripping water away from the rest of the underlying roofing structure

Eave – lower edge of a sloped roof that extends down past the wall

Eave vent – opening along the edge of the roof used to dissipate heat and moisture

Fascia – a flat board at the cornice’s outer edge, running along the eaves of the roof

Flashing – elements used to weatherproof or seal roof edges at perimeters, walls, expansion joints, drains and other areas where roofing material ends

Gable – section of a sidewall that forms a triangle at the ridge of a sloped roof

Interlocking shingles – individual shingles that attach to each other and don’t require sealing strips, used to provide extra wind resistance

Laminate – process of joining layers together using some type of adhesive (like mastic)

Rafter – a component designed to support the deck and roofing system, usually installed from the highest point (ridge) to the eave

Rake – inclined edge of a roof over a wall

Soffit – finished underside of the eaves

Truss – triangular structure used for support; multiple trusses are used to assemble the roof’s framework

Vent – a pipe or stack that protrudes through the roof deck to ventilate the underside of the deck

For any other questions about roof terms and definitions or if you need any roofing services in the Maryland, Washington, DC and Virginia area, contact Shanco today!



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