Roofing Terms Glossary

Also known as dimensional or laminated shingles. They are premium asphalt shingles composed of multiple layers, creating a dimensional/shadow texture that mimics slate or wood shakes and lasts longer than standard 3-tab shingles.

The space immediately beneath the roof framing and above the ceiling of the top story of a house. Proper attic ventilation is critical to manage temperature and moisture.

A package of shingles sold by manufacturers. For asphalt shingles, three bundles typically cover exactly one roofing square (100 square feet) of roof surface area.

A horizontal framing member (lumber) connecting opposing rafters in the upper third of a roof slope. They prevent the rafters from spreading or sagging under heavy wind or snow loads.

A structural element of a building that protrudes vertically from the plane of a sloping roof. Dormers contain windows and add usable space/light to attics, but increase roof calculation complexity.

An L-shaped metal flashing strip installed along the eaves and rake edges of a roof. It directs water away from the fascia board and into the gutters, preventing water infiltration under shingles.

The horizontal lower edge of a roof that overhangs or extends past the exterior walls of a house, where gutters are typically installed.

A highly durable synthetic rubber single-ply waterproofing membrane commonly used on low-slope and flat roofs. It is highly resistant to heat, UV rays, and weathering.

The flat, vertical wooden or metal board mounted along the roof edge at the eaves, supporting the gutters and enclosing the ends of the rafters.

Thin metal sheets (usually galvanized steel, copper, or aluminum) installed around roof joints, valleys, chimneys, and walls to direct water flow away from seams and prevent leaks.

A classic roof design featuring two sloping planes that meet at a center ridge, creating a triangular wall extension (the gable) at each end.

A Dutch-style barn roof characterized by two slopes on each side, with the lower slope being much steeper than the upper slope to maximize interior attic headroom.

A roof design where all four sides slope downward toward the exterior walls, with no vertical gables. It is highly stable and recommended for high-wind areas.

A self-adhering, rubberized asphalt underlayment applied along eaves, valleys, and vulnerable joints. It acts as a waterproof barrier to protect against leaks caused by ice dams.

A French-style four-sided roof with a double slope on each side, where the lower slope is nearly vertical and contains dormer windows, and the upper slope is low-pitched.

A engineered wood sheathing panel made from compressed wood strands and waterproof adhesives. It is the most common material used for roof decking.

The portion of the roof structure that extends beyond the exterior walls of the house. Eave overhangs run horizontally, while rake overhangs slope up the gable ends.

The angle or slope of a roof, expressed as the vertical rise in inches for every 12 inches of horizontal run (e.g., 6/12 pitch rises 6 inches per foot).

A strong decking panel made of thin layers of wood veneer glued together with alternating grain directions. Premium alternative to OSB for roof sheathing.

Polyvinyl Chloride single-ply roof membrane. It is extremely durable, weldable, fire-resistant, and chemically stable, making it a premium choice for flat roofs.

A sloped structural lumber beam that supports the roof decking and external roofing materials, running from the ridge board to the eave.

The sloped outer edges of a gable roof extending from the eave up to the ridge peak.

The peak horizontal line formed where two sloping roof planes meet at the highest point of the roof structure.

Special shingles or metal covers designed to fit over the ridge peak to seal the joint between opposing roof slopes and prevent leaks.

A standard unit of measure in roofing, representing exactly 100 square feet of roof surface area. Materials like shingles and underlayment are priced and ordered by the square.

A single-slope roof design resembling a lean-to. Often used for home additions, porches, and modern residential architectures.

A geometric multiplier (pitch multiplier) used to convert a flat horizontal footprint area into the true sloped roof surface area.

The underside of the roof overhang, located between the fascia board and the home's exterior wall. Often contains intake vents to draw cool air into the attic.

A single-ply reflective flat roofing membrane made of rubber and polypropylene. It is highly energy-efficient and heat-reflective.

A water-resistant barrier (usually asphalt-saturated felt or synthetic woven polymer) installed directly over the wood roof decking before laying shingles.