Roofing Terms Glossary

The words you’ll hear from a roofer

Plain-English definitions for the terms used on quotes, insurance scopes, and inspection reports — so you can make informed decisions about your roof.

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1 term

3-Tab Shingle: A flat, single-layer asphalt shingle with three uniform tabs. Lowest cost and the thinnest profile; largely replaced by architectural shingles.

5 terms

ACV (Actual Cash Value): The depreciated value of your roof at the time of loss. Older policies or older roofs often pay ACV only.
Algae Streaks: Dark horizontal stains caused by Gloeocapsa magma algae — common in humid climates.
Architectural Shingle: A multi-layer "dimensional" asphalt shingle that simulates the depth of wood shakes. Standard on most modern homes.
Asphalt Shingle: The most common residential roofing material, made of a fiberglass mat coated in asphalt and surfaced with mineral granules.
Attic Ventilation: The balanced airflow (intake + exhaust) that keeps an attic dry and cool — critical for shingle longevity.

4 terms

Blistering: Raised bubbles on shingles, usually caused by moisture trapped in the mat or poor attic ventilation.
Boot / Penetration: Any object passing through the roof (pipes, vents, skylights) that needs its own flashing.
Box Vent: A passive static vent installed near the ridge to release attic heat.
Built-Up Roof (BUR): A traditional multi-ply flat roof made of alternating layers of bitumen and fabric, finished with gravel.

2 terms

Counter Flashing: A second flashing piece mounted into a chimney or wall to cover the top edge of step flashing.
Curling: Shingle corners that turn upward — a sign of age, poor ventilation, or heat stress.

4 terms

Deductible: The portion of a claim you pay before the insurer pays anything. For roofs, this is often 1–2% of the dwelling limit.
Dormer: A vertical window projection that sticks up from a sloped roof.
Downspout: The vertical pipe that carries water from the gutter to the ground.
Drip Edge: Metal flashing installed at the eaves and rakes to shed water away from the fascia and deck.

3 terms

Eave: The lower horizontal edge of a roof where the gutter is attached.
EPDM: Ethylene Propylene Diene Monomer. A black synthetic-rubber single-ply flat-roof membrane known for longevity.
Exposure: The portion of each shingle left visible after the next course overlaps it — typically 5-5/8 inches.

2 terms

Fascia: The vertical board that runs along the eave where gutters are mounted.
Flashing: Thin metal pieces installed around chimneys, walls, skylights, and valleys to direct water away from joints.

4 terms

Gable: The triangular wall section between two sloping roof planes.
Granule Loss: Loss of the mineral granules that protect asphalt shingles — common in older roofs or after hail.
Gutter: The channel along the eave that collects rainwater from the roof and directs it to downspouts.
Gutter Guard: A screen or cover installed over a gutter to keep out leaves and debris.

1 term

Hip: An external sloped edge where two roof planes meet (not the ridge).

3 terms

Ice & Water Shield: A self-adhered membrane installed in valleys, along eaves, and around penetrations to block wind-driven rain and ice dams.
Ice Dam: A ridge of ice formed at the eave that blocks meltwater and forces it back under the shingles.
Impact-Resistant Shingle: A Class 4 UL 2218–rated shingle designed to resist hail. May earn an insurance discount in Texas and Louisiana.

3 terms

Lifting: Shingles that have lost their seal, often after high winds or improper installation.
Linear Footage (LF): The total length of an edge feature (ridge, hip, valley, eave, or rake) in feet.
Low Slope: A roof with a pitch less than 2/12 — requires membrane or built-up systems, not shingles.

3 terms

Manufacturer Warranty: Coverage on shingles themselves — covers defects in materials, not workmanship.
Metal Roofing: A long-life roof made of steel, aluminum, copper, or zinc — available as standing-seam panels or stone-coated steel.
Modified Bitumen: A multi-ply asphalt-based flat-roof system (torch-down or peel-and-stick) used on low-slope roofs.

1 term

Nail Zone: The manufacturer-specified band on each shingle where nails must be placed for the warranty to apply.

1 term

Overlay / Recover: Installing new shingles directly over an existing layer. Most codes allow at most two layers total.

6 terms

Pipe Boot: A flashing collar with a rubber gasket that seals around plumbing vent pipes.
Pitch: The steepness of the roof, typically expressed as rise-over-run (e.g., 6/12 means 6 inches of rise per 12 inches of run).
Plane / Facet: A single flat surface of the roof bounded by eaves, rakes, hips, valleys, or the ridge.
Ponding Water: Water that remains on a flat roof more than 48 hours after rain — warranty exclusion on many membranes.
Power Vent: A fan-driven attic exhaust vent, often solar or thermostat-controlled.
PVC Membrane: A heat-welded single-ply flat-roof membrane that resists chemicals and grease — popular on restaurants and warehouses.

7 terms

Rafter: A sloped framing member that supports the roof deck. Modern homes often use trusses instead.
Rake: The sloped, angled edge of a gable roof.
RCV (Replacement Cost Value): The full cost to replace your roof with like-kind materials — paid in two parts (ACV up front, depreciation after completion).
Ridge: The highest horizontal edge where two roof planes meet at the peak.
Ridge Cap: Thicker, hip- and ridge-specific shingles that bend over the peak to finish the roof.
Ridge Vent: A continuous vent running along the ridge that exhausts hot attic air.
Roof Deck: The structural wood (plywood or OSB) that roofing materials are fastened to.

11 terms

Scupper: An opening in a parapet wall that lets water drain from a flat roof to the exterior.
Seamless Gutter: Gutter formed on-site in one continuous piece (except at corners) to minimize leaks.
Soffit: The underside of the roof overhang, usually vented to allow attic airflow.
Soffit Vent: Intake vents installed in the soffit that let cool air into the attic.
Square: 100 square feet of roofing. Materials and labor are priced per square.
Standing Seam: A metal roof with raised, interlocking vertical seams between panels. Fasteners are hidden.
Starter Strip: A pre-adhered strip installed at the eaves and rakes so the first course of shingles has a factory seal.
Step Flashing: L-shaped flashing pieces woven between shingles where a roof meets a vertical wall.
Supplement: An additional payment request filed with the insurer for items missed in the original scope.
Synthetic Underlayment: A woven-polymer underlayment that outlasts traditional felt and is safer to walk on.
System Warranty: An upgraded manufacturer warranty (e.g., GAF Silver Pledge, Golden Pledge) that covers the full roof system when installed by a certified contractor.

3 terms

Tear-Off: Complete removal of the old roof down to the deck before installing a new one.
TPO: Thermoplastic Polyolefin. A white, single-ply commercial flat-roof membrane that reflects heat and is heat-welded at the seams.
Truss: A pre-built triangular framing assembly that supports the roof and ceiling.

1 term

Underlayment: A layer rolled over the roof deck before shingles are installed. Adds a second line of defense against water.

1 term

Valley: An internal angle where two roof planes meet — a natural channel for runoff.

2 terms

Waste Factor: Extra material (usually 10–15% for steeper or cut-up roofs) ordered to account for cuts, breakage, and pattern matching.
Workmanship Warranty: Coverage on the installer's labor — separate from the manufacturer warranty.

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