What does drip edge go on?
What it attaches to
The roof flange of a drip edge lies flat on the plywood or OSB decking and is nailed through the deck, not into the fascia. The vertical leg hangs in front of the fascia board with a small gap and a kick-out at the bottom so water drips clear. The International Residential Code requires it at the eaves and rakes of shingle roofs, extending at least 2 inches onto the deck and at least 1/4 inch below the sheathing, fastened no more than 12 inches apart, with pieces lapped at least 2 inches.
The order of layers
- At the eaves: drip edge first, then underlayment or ice and water membrane over it, so water running down the underlayment lands on top of the metal.
- At the rakes: underlayment first, then drip edge over it, so wind-driven rain cannot get behind the underlayment at the side edge.
- Starter strip and shingles on top, overhanging the drip edge slightly.
Where gutters fit
On a guttered eave, the drip edge should drop water into the gutter, not behind it. When the gutter hangs low or the fascia is uneven, roofers use a profile with a longer leg or a gutter apron that reaches down into the gutter. A gap between drip edge and gutter is a common reason for rotted fascia and stained siding on Georgia homes. See gutter sizing, seamless gutters and guards.
For the full rundown, read drip edge explained.