What is the difference between drip cap and drip edge?
Drip edge: the roof's edge
Drip edge runs along the eaves and rakes. Its flange lies on the roof deck under the underlayment or shingles, and its face hangs over the fascia with a small lip that throws water into the gutter. The residential code calls for it on shingle roofs. Its job is to keep runoff from wicking back onto the deck edge and fascia.
Drip cap: the wall's ledges
Drip cap, sometimes called head flashing, sits on top of window and door trim, band boards and other horizontal pieces on a wall. It tucks up behind the house wrap and siding above, then slopes out over the trim with a small drip lip. A similar Z-shaped flashing goes between courses of panel siding. Without it, water running down the wall settles on top of the trim and works into the framing.
Why both matter
They protect different water paths, and failures in either can look alike from inside. A stain near the top of a window is often blamed on the roof when the real cause is missing head flashing, or the reverse. Tracing the water to its source saves paying for the wrong repair.
Signs drip cap is missing or failing
- Soft or rotting wood at the top of window or door trim.
- Peeling paint on head casings.
- Stains on the interior wall below a window corner.
Where they meet
Where a roof runs alongside a wall, step flashing and a kickout flashing tie the two systems together. That junction is a frequent leak point; see common causes of roof leaks, and for roof edges specifically, drip edge explained.