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Roofing glossary

Plain-English definitions for the terms contractors use — so you know exactly what's being quoted.

What Is Class 4 Impact Rating?

Class 4 is the highest impact-resistance rating under UL 2218 testing standards, indicating a shing…

What Is Drip Edge?

Drip edge is a metal flashing strip installed along the roof's eaves and rakes that directs water a…

What Is Eave?

The eave is the lower edge of a roof that overhangs the exterior wall, directing water away from th…

What Is Fascia?

Fascia is the vertical board running along the edge of the roofline, typically where gutters are mo…

What Is Flashing?

Flashing is thin sheet metal installed at roof joints and penetrations to redirect water away from …

What Is Gable Roof?

A gable roof has two sloping sides meeting at a ridge, with triangular vertical wall sections (gabl…

What Is Hip Roof?

A hip roof slopes on all four sides with no vertical gable ends, generally offering better wind res…

What Is Ice & Water Shield?

Ice and water shield is a self-adhered, waterproof underlayment installed at roof eaves and valleys…

What Is Rafter?

Rafters are the sloped structural framing members that support the roof deck, running from the ridg…

What Is Ridge Vent?

A ridge vent is a ventilation component installed along the roof's peak that allows hot, moist atti…

What Is Roof Decking?

Roof decking (or sheathing) is the structural wood layer — typically plywood or OSB — fastened to t…

What Is Roof Pitch?

Roof pitch is the steepness of a roof, expressed as a ratio of vertical rise to horizontal run (e.g…

What Is Roof Truss?

A roof truss is a pre-engineered, factory-built triangular structural framework that supports the r…

What Is Roof Underlayment?

Underlayment is a water-resistant layer installed between the roof deck and the visible roofing mat…

What Is Roof Valley?

A roof valley is the internal angle formed where two roof planes meet and slope toward each other, …

What Is Soffit?

The soffit is the underside surface of a roof's eave overhang, typically ventilated to allow fresh …

What Is Standing Seam?

Standing seam is a metal roofing style with raised, interlocking vertical seams and no exposed fast…

What Is Vapor Barrier?

A vapor barrier is a material layer that limits moisture (water vapor) movement through the roof or…