What is the purpose of drip edge?
Short answer. Drip edge directs water off the roof edge and into the gutter or away from the house, instead of letting it curl back under the shingles and soak the fascia and deck edge. It also supports the overhanging shingle edge, closes the gap that lets insects and small animals into the eave, and helps keep wind from getting under the first course.
Each job, explained
- Breaking the water path: water clings to the underside of a bare shingle edge and runs back toward the house. The drip edge's face and kick give it a clean place to drop off, into the gutter or onto the ground.
- Protecting wood: the top of the fascia and the edge of the deck are end grain that soaks up water quickly. Covering them prevents the rot that shows up as soft fascia and crumbling deck edges.
- Supporting shingles: the shingle overhang rests on the metal, so it does not sag, crack or curl down over time.
- Sealing the gap: there is often a small gap between the deck and fascia. Drip edge covers it, keeping out wasps, carpenter bees, birds and squirrels.
- Wind resistance at edges: a stiff edge under a sealed starter strip helps keep wind from catching the first course.
- Code compliance: the IRC requires it at eaves and rakes of shingle roofs.
- A finished look: a straight, color-matched line along the roof edge.
Why it matters in Georgia
Heavy summer downpours send large volumes of water to the roof edge in minutes, and humid weather keeps any wet wood wet. Homes without drip edge here commonly need fascia and deck edge repairs by the time the roof is replaced.
Small part, big payoff
Drip edge is one of the least expensive components of a roof, while replacing rotted fascia, soffit and deck edges costs far more.