NCCER Roofing key terms

The incline of a roof surface stated as a ratio of vertical rise to horizontal run, such as 4:12. Slope controls which underlayments, fastening methods, and flashing details a crew may use.

A traditional way of expressing roof steepness as a fraction of the span, often written with the rise over twice the run. Crews still use the term informally on the jobsite.

A roof with a slope generally at or below 3:12. These roofs normally require membrane or built-up systems rather than standard shingles and demand careful drainage design.

The lower edge of a sloped roof that projects past the exterior wall. Eaves shed water away from the building and typically receive edge metal, underlayment, and the first courses of roofing.

The inclined edge of a sloped roof at a gable end, running from eave to ridge. Rakes are finished with rake edge metal or trim and are common wind-uplift locations.

The highest horizontal line where two opposing roof planes meet. The ridge is capped with ridge material, and its height sets the total rise used in slope calculations.

An external roof edge formed where two sloping planes meet at an outside corner. Hip roofs have hips instead of gables and need hip flashing or hip and ridge cap products.

The internal intersection where two roof planes meet and concentrate water flow. Valleys require special flashing or lining and are the most leak-prone area of a steep-slope roof.

The triangular section of wall at the end of a pitched roof, or the roof style that ends in that triangle. Gable ends are closed with siding or rake trim above the wall line.

A sheet material installed over roof decking beneath the finished roof covering. It provides a secondary weather barrier and is required by code on most steep-slope assemblies.

The structural surface that receives roofing materials, usually plywood, oriented strand board, or plank sheathing. Deck condition, thickness, and fastening determine whether a new roof can be installed.

The panels or boards fastened to rafters or trusses to form the roof deck. Sheathing must be properly gapped, nailed, and sound before underlayment and covering go down.

Metal flashing installed along eaves and rakes to direct water off the roof and away from fascia. It also helps support the overhanging edge of shingles.

Metal or membrane material used to seal roof joints and penetrations against water entry. Flashing is installed at walls, valleys, chimneys, skylights, and vent pipes.

L-shaped metal pieces woven into each course of shingles where a sloped roof meets a sidewall. Each piece sheds water onto the shingle below rather than behind it.

Flashing embedded in or attached to a wall or chimney that laps over the base flashing below. It keeps water from getting behind the lower flashing.

A self-adhering waterproof membrane installed along eaves and in valleys before underlayment. It protects against water backup caused by ice dams and is required in many cold-climate codes.

A ridge of ice that forms at the eave and traps melting snow water, forcing it under shingles. Causes include heat loss through the roof and inadequate attic ventilation.

Intake and exhaust openings that move air through the attic or roof assembly. Good ventilation reduces heat buildup, moisture condensation, and ice dam formation.

A continuous exhaust vent installed along the ridge under the ridge cap. It works with soffit intake vents to create balanced airflow through the attic.

The underside surface of an eave overhang, often fitted with intake vents. Soffit vents supply the low air needed for a balanced ridge-vent system.

The finished board along the eave that covers the rafter ends and supports the gutter. Fascia is often replaced when drip edge or gutter work is performed.

A roof covering made of asphalt-saturated felt or fiberglass mat coated with mineral granules. It is the most common steep-slope product and is rated by wind and fire class.

The first row of shingles or starter strip installed at the eave before field shingles. It seals the eave edge against wind-driven rain and wind uplift.

A horizontal row of shingles laid across the roof. Courses overlap according to the manufacturer's exposure requirement so water sheds down the roof.

The portion of a shingle course left uncovered by the next course above. Exposure is set by the manufacturer and determines coverage, nailing pattern, and the number of courses.

The required number and placement of fasteners for each shingle or panel. Manufacturers specify pattern and nail location, and inspectors check it closely because it controls wind resistance.

A nail, screw, or staple used to attach roofing components to the deck or framing. Fastener type, length, and corrosion resistance must match the material and code requirements.

A sheet or fluid-applied layer that resists water under hydrostatic pressure. It is used on low-slope roofs and in critical details such as valleys and parapet walls.

A low-slope roof made of alternating layers of bitumen and reinforcing ply felt, topped with surfacing. Layer count gives the roof its designation, such as a three-ply system.

A rolled low-slope membrane made of asphalt blended with modifiers such as SBS or APP rubber. It is applied by torch, hot asphalt, or adhesive depending on the product.

A flexible sheet membrane such as TPO, PVC, or EPDM used on low-slope roofs. Sheets are joined by heat welding or adhesive and are fastened or ballasted to the deck.

A low wall extending above the roof edge, common on commercial buildings. Parapets need base flashing, counterflashing, and coping to keep water out of the wall assembly.

The cap installed on top of a parapet wall to shed water away from the wall face. Coping joints and end laps must be sealed to prevent leakage behind flashing.

A fitting that carries water from a low-slope roof surface into the building's drainage piping. Drains need strainers and must sit at the low point of the roof slope.

An opening through a parapet or wall that lets roof water drain to the exterior. Scuppers are used with roof drains or as emergency overflow paths.

Systems and practices that prevent workers from falling from roof edges or openings. Common measures include guardrails, personal fall arrest, and warning lines required by safety rules.

A bracket that supports staging or planks on a sloped roof and protects the roof surface. Roof jacks must be installed securely and removed before the final courses are completed.