Testing Drip Edge Installations on Roofing
Ask This Old House general contractor Tom Silva demonstrates the importance of a properly installed drip edge
- A roof without a drip edge can draw water off the roof into the end grain of the sheathing through surface tension, rotting the sheathing, the fascia, and the structure underneath.
- A metal drip edge will help protect the sheathing under the roof, but if it’s installed too closely to the fascia board, it can still cause water to be drawn into the fascia.
- The best installation method is to leave a gap between the drip edge and the fascia board, about the width of a finger. The shingles should also overhang the drip edge 3⁄8 to 1/2 an inch.
Drip edges and shingles can be found at home centers.