How Drip Edge Works
Drip edge is a bent piece of metal, usually aluminum or galvanized steel, that runs along the eaves (the bottom edges) and rakes (the sloped side edges) of your roof. Its L-shaped or T-shaped profile has a small lip that kicks water outward, so runoff drips off the edge instead of curling back underneath the shingles.
It is installed in a specific order relative to the underlayment and shingles: at the eaves it goes under the underlayment, and at the rakes it goes over the underlayment. This layering forces water to stay on top of the roof surface and flow into the gutter rather than seeping behind it.
Why Drip Edge Matters in the Inland Northwest
In the Spokane and North Idaho climate, drip edge does far more than tidy up the look of a roofline. Our long winters bring repeated freeze-thaw cycles, heavy snow loads, and ice dams that push water sideways and upward against the roof edge.
- Ice dams: When melting snow refreezes at the cold eave, water can back up under shingles. Drip edge gives that water a defined exit path and shields the vulnerable edge of the decking.
- Freeze-thaw: Wood fascia that gets repeatedly wet and frozen will rot and warp. Drip edge keeps that water off the wood entirely.
- Wind-driven rain: The metal lip prevents gusts from driving water back beneath the roof covering.
Without it, water wicks behind the gutters and into the fascia and sheathing, causing rot, mold, and expensive structural repairs that often go unseen until they are severe.
Drip Edge and Roof Replacement
Modern building codes and GAF installation standards call for drip edge on new roofs, and it is one of the components most often missing or improperly installed on older homes. If your roof was built before drip edge was standard, or if you are seeing peeling fascia paint and water staining along the eaves, it may not have adequate edge protection.
A full roof replacement is the ideal time to add or correct drip edge, because it must be integrated with the underlayment and first course of shingles to work properly. As a GAF Master Elite contractor, DG Contracting installs drip edge to manufacturer specification on every project.
Signs Your Drip Edge May Be Failing
Drip edge is durable, but it can be damaged, corroded, or simply absent. Watch for these warning signs around your roof perimeter:
- Water stains or rot on the fascia boards or soffit
- Gaps or rust along the metal edge of the roof
- Granules and debris collecting where water spills behind the gutter
- Peeling or bubbling paint just below the roofline
- Gutters pulling away from the house
If you notice any of these, it is worth a professional look before the damage reaches the decking.