Roofing Terms Glossary

Helpful Roofing Terms & Roofing Definitions

Check out the top roofing terms and roofing definitions to make it as easy as possible to discuss your needs with our team.

A bituminous waterproofing agent applied to roofing materials during manufacturing.

Back Surfacing
Fine mineral matter applied to the back side of shingles to keep them from sticking.

Bubbles that may appear on the surface of asphalt roofing after installation.

Built-Up Roof
A flat or low-sloped roof consisting of multiple layers of asphalt and ply sheets.

To fill a joint with mastic or asphalt cement to prevent leaks.

Class "A"
The highest fire-resistance rating for roofing as per ASTM E-108.  Indicates roofing is able to withstand severe exposure to fire originating from sources outside the building.

Class "B"
Fire-resistance rating that indicates roofing materials are able to withstand moderate exposure to fire originating from sources outside the building.

Class "C"
Fire-resistance rating that indicates roofing materials are able to withstand light
exposure to fire originating from sources outside the building.

Concealed Nail Method
Application of rolled roofing in which all nails are driven into the underlying course of roofing and covered by a cemented, overlapping course.  Nails are not exposed to the weather.

The change of water from vapor to liquid when warm, moisture-laden air comes in contact with a cold surface.

Amount of weather protection provided by the roofing material.

The surface, usually plywood or oriented strand board (OSB), to which roofing materials are applied.

A small structure projecting from a sloped roof, usually with a window.

A pipe for draining water from roof gutters.  Also called a leader.

Drip Edge
An L-shaped strip (usually metal) installed along roof edges to allow water run-off to drip clear of the deck, eaves and siding.

The horizontal lower edge of a sloped roof.

Edging Strips
Boards nailed along eaves and rakes after cutting back existing wood shingles to provide secure edges for re-roofing with asphalt shingles.

A flat board, band or face located at a cornice's outer edge.

A sheet of asphalt-saturated material (often called tar paper) used as a secondary layer of protection for the roof deck.

Pieces of metal or roll roofing used to prevent seepage of water into a building around any intersection or projection in a roof such as vent pipes, chimneys, adjoining walls, dormers and valleys.

Fire Rating
System for classifying the fire resistance of various materials. Roofing materials are rated Class A, B or C, with Class A materials having the highest resistance to fire originating outside the structure.

The upper portion of a sidewall that comes to a triangular point at the ridge of a sloping roof.

Ceramic-coated colored crushed rock that is applied to the exposed surface of asphalt roofing products.

The trough that channels water from the eaves to the downspouts.

A rigid board of various widths from 1/2 "to 6", usually applied with some form of mechanical fasteners. When more than one layer is applied the second layer will be applied with an adhesive, either hot or cold.

Interlocking shingles
Individual shingles that mechanically fasten to each other to provide wind resistance.

Slatted devices installed in a gable or soffit (the underside of eaves) to ventilate the space below a roof deck and equalize air temperature and moisture.

Oriented strand board (OSB)
Roof deck panels (4 by 8 feet) made of narrow bits of wood, installed lengthwise and crosswise in layers and held together with a resin glue. OSB often is used as a substitute for plywood sheets.

That portion of the roof structure that extends beyond the exterior walls of a building.

Vents, pipes, stacks, chimneys—anything that penetrates a roof deck.

The degree of roof incline expressed as the ratio of the rise, in feet, to the span, in feet.

The supporting framing to which a roof deck is attached.

The inclined edge of a roof over a wall.

The top edge of two intersecting sloping roof surfaces.

The boards or sheet materials that are fastened to rafters to cover a house or building.

The finished underside of the eaves.

Measured by rise in inches for each 12 inches of horizontal run: A roof with a 4-in-12 slope rises 4 inches for every foot of horizontal distance.

The common measurement for roof area. One square is 100 square feet (10 by 10 feet).

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

A layer of asphalt saturated (sometimes referred to as tar paper) which is laid down on a bare deck before shingles are installed to provide additional protection for the deck.

The angle formed at the intersection of two sloping roof surfaces.

Vapor Retarder
A material designed to restrict the passage of water vapor through a roof
system or wall.

Any device installed on the roof, gable or soffit for the purpose of ventilating the underside of the roof deck.

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