How to Install Drip Edge Flashing

Drip edge is the silent guardian of your roof deck. Without this simple L-shaped piece of metal, water curling around the edge of your shingles will inevitably soak the fascia board and rot the sub-roofing. Done well, it creates a seamless transition that forces water to drop directly into your gutters rather than wicking back underneath your roofing materials. Installing it correctly requires understanding the sequence of water flow. You want to layer the flashing so that each subsequent layer overlaps the one below it. When you get this right, you save yourself years of structural damage and expensive wood repairs. It is the cheapest insurance policy you can buy for your home's exterior.

1. Measure Twice, Cut Once. Measure the length of your eaves and rakes, adding two inches for overlaps. Use tin snips to cut the drip edge to length, keeping your cuts clean and straight to prevent buckling.
2. Seat the Eave Edge. Place the drip edge directly onto the roof deck along the eaves, with the flange overlapping the fascia board. Ensure the metal is flush against the wood to prevent rattling in the wind.
3. Nail It Down Tight. Nail the top flange into the roof deck using roofing nails every 12 inches. Space your nails consistently to keep the metal tension even across the entire perimeter.
4. Layer the Underlayment. Roll your roofing felt or synthetic underlayment over the eave drip edge. The underlayment should extend about an inch over the metal flange to provide a final protective layer.
5. Flip the Script at Rakes. Along the sloped rake edges, install the drip edge over the underlayment. This reverses the order used at the eaves, ensuring water running down the rake flows over the metal rather than behind it.
6. Seal the Weak Spots. At the corners where the rake meets the eave, miter the drip edge for a clean, professional finish. Ensure no gaps exist where wind-driven rain could penetrate the corner joint.