What is drip edge on a roof, and how is it installed?
Short answer. Drip edge on a roof is the L or T shaped metal flashing nailed along the eaves and rakes so water drips clear of the fascia and into the gutter. Roofers install it at the eaves before the underlayment and at the rakes after the underlayment, lapping each piece and nailing it to the deck.
The common profiles
- L-style (often called Type C). A simple bent angle. Cheap and common, but water can cling to the bottom edge.
- T-style (often called Type D). Has a flared lip that kicks out past the fascia so water drips cleanly. A better choice for most Georgia eaves.
- Gutter apron. A longer leg that reaches down into the gutter, used where the gutter sits low.
How it is installed
- Old drip edge comes off with the old roof, and the deck edge and fascia are checked for rot.
- Eave drip edge goes on the bare deck, nailed into the decking, not the fascia, at 12 inches or closer.
- Underlayment or ice and water membrane laps over the eave metal.
- Rake drip edge goes on top of the underlayment along the sloped edges.
- Pieces lap at least 2 inches, and corners are cut and folded so the rake piece overlaps the eave piece and sheds water downhill.
- Starter strip and shingles finish the edge, overhanging the metal slightly.
Common mistakes
Nailing into the fascia instead of the deck, reversing the lap order at the eaves, setting the bottom edge tight against the fascia so water wicks behind it, and skipping the rakes. Each one leads to fascia rot. Fasteners should be compatible with the drip edge metal, so aluminum edge gets aluminum or galvanized nails, never copper. For the code rule and more detail, see drip edge explained and roof flashing explained.