Roofing Terminology

Once you have realized that you have a need for roofing work, it is important to be able to discuss your options for repair or replacement with your contractor. Knowing the common language and terms used in the roofing industry will help immensely in this pursuit.  In an effort to help, the following is a handy list of some of the most important terms commonly used among roofing contractors.

Algae Discoloration
Black streaks or discoloration caused by the growth of Algae on your roof.

Architectural Shingles
Also called dimensional or laminated shingles, these are made from fiberglass and asphalt. They are then laminated or textured to give them an attractive 3D look.

Blisters
Bubbles that may appear on the asphalt roofing materials after they are installed.

Bundle
A package of shingles, 3 bundles of standard shingles will cover one roofing square. [10’x10′ or 100 sq. ft.]

Caulk
Used to fill joints or cover nail heads to prevent leaks.

Closed Valley
A type of valley where the shingles are installed over the valley flashing, so that the flashing is not exposed.

Collar
A flange placed over a stack type vent to seal the roof around the pipe, also sometimes referred to as a vent sleeve.

Counter Flashing
A flashing that is attached to a vertical surface (such as a wall) to prevent water from seeping under a base flashing.

Course
This is a row of shingles that runs the length of the roof.

Decking
This is the plywood that covers the roof’s wooden frame. The deck or decking can also be called sheathing.

Dormer
A small structure projecting from a sloped roof that usually has a window.

Drip Edge
A kind of flashing that is usually made of steel goes along eaves at a 90° angle to direct rain water runoff into the roof gutters. A non-corrosive metal flashing installed along the lower edge and often up the rake of the roof. Its purpose is to direct water draining from a roof into the gutters preventing damage to the underlying construction.

Eave
An eave is the horizontal lower edge of a sloped roof that overhangs the exterior wall of the home or building.

Fascia
Often called ‚”the boards behind the roof gutters”, this vertical roof trim is found just under the roof where it covers the rafter tails at the eaves.

Felt
A paper-like material used as a protective layer on top of the decking and under the roof’s shingles. It is often impregnated with asphalt and acts as an additional water barrier.

Flashing
This is usually made of metal and is used to help prevent leaks around roof elements like pipes, chimneys, dormers, and valleys.

Gable Roof
A 2-sided roof with matching slopes on either side.

Granules
Ceramic-coated, crushed rocks that are applied to the exposed surface of asphalt shingles. These granules are often colored.

Hip Roof
A roof with four sloping sides of the same pitch. There will be no gables on a Hip Roof.

Ice Dam
Ice formed at the lower edge of a roof that is caused by the thawing and re-freezing of melted snow. An ice dam can force water under the shingles.

Ice & water shield
An impenetrable roofing membrane installed under shingles to prevent water that may seep under the shingles from entering the house, normally installed at the eaves edge.

Louvers
Slatted devices installed in a gable or soffit to ventilate the space below a roof deck and equalize air temperature and moisture.

Leak Barrier
This is a self-adhering and self-sealing material which is applied to the roof’s deck to protect it from severe rain storms.

Mansard Roof
A roof with an extreme pitch, often it will appear vertical. These roofs will sometimes have a flat roof on top, or a low sloped hip roof.

Overlay
A term used to describe installing a second or third layer of shingles. This is not a recommended practice.

Pitch
The roof incline measured as the ratio of the rise, in feet, to the run, in feet. This is also referred to as the slope.

Ply
The number of layers of roofing material, i.e. one-ply or two-ply.

Rafter
The individual pieces of wood that make up the roof’s frame are referred to as Rafters. Rafters support the decking and extend from the peak of the roof down to where the roof meets the exterior walls. Rafter Tailsare the end points of the rafters.

Rake
The inclined edge of a roof.

Ridge
The uppermost angle of the roof, where the two slopes meet.

Rise
The vertical distance from the eaves line to the ridge of the roof.

Roofing Square
100 square feet of roofing material installed with proper exposure. It is not literally 100 square feet of roofing material, however, it is the amount of material required to cover 100 square feet of a roof deck.

Run
The horizontal distance from the eaves to a point directly under the ridge. This is always one half of the span of the roof.

Roof Ventilation
An important system for removing hot air and moisture from the attic area, proper ventilation can be power-driven or static and is critically important to the roof’s ability to maintain a comfortable inside temperature level.

Stack Vent
A vent pipe used for ventilation from sewage drains in the house.

Starter Strip
Shingles applied at the roofs edge to provide protection under the cutouts and joints of the first course of shingles.

Step Flashing
Flashing used to protect areas where a vertical surface meets a slope.

Soffit
This is the finished underside of the eaves, or roof overhang.

Tab
The exposed portion of a shingle, defined by a cutout.

Truss
Engineered components that supplement rafters in many newer homes and buildings. Trusses are designed for specific applications and cannot be cut or altered.

Valley
The intersection formed by two slopes meeting.