Know Your Roof · Flashing & Roof Edge
Drip Edge: What It Is and Why Your Roof Needs It
Quick answer
Drip edge is a strip of L-shaped metal flashing along the edges of a roof. It sends water off the shingles and into the gutter, and keeps it from soaking the roof deck and fascia. It's a cheap part that protects wood that rots easily.
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What it does
It directs water into the gutters, away from the fascia. It protects the edge of the roof deck from moisture. It helps keep pests from getting in under the shingles. And it gives the shingles a clean edge to hang over.
Under or over the underlayment?
At the eaves, drip edge goes under the underlayment, so water runs down onto the metal. At the rakes, it goes over the underlayment. The order matters: put it in backward and water can get under the metal.
Types
Type C is the simple L shape. Type D has a hemmed or T-style edge, with an extra lip for stiffness and a drip line. A gutter apron is an extended version made to reach over the gutter.
Is it required?
Current residential building codes based on the International Residential Code call for drip edge at the eaves and rakes of asphalt shingle roofs, and many shingle manufacturers call for it in their instructions. Confirm with your local building department.
Signs it's missing or damaged
Rotted fascia. Water staining behind the gutters. Shingles curling at the edge. Rust on older metal.
Looking for another word? See the roofing terms glossary, A to Z.