What Is Drip Edge?
Drip edge is the metal flashing installed at your roof's eaves and rakes to direct water off the deck and away from your fascia. Here's why it matters.
Drip edge is a metal flashing — typically a bent L- or T-shaped strip of aluminum or galvanized steel — installed along the lower edges and angled side edges of your roof. Its job is to direct water off the deck and away from the fascia and soffit below. It's not decorative and it's not optional: IRC Section R905.2.8.5 requires it on all asphalt shingle roofs, and most Texas building departments enforce that requirement.
What drip edge actually does
When rain hits your roof, it flows down the shingles toward the eave. Without drip edge, water at the edge tends to follow the fascia board by capillary action — a slow creep that causes rot before you ever notice a leak inside. Drip edge breaks that capillary path. The flashing extends at least a quarter inch below the roof sheathing, forcing water to drip clear of the fascia rather than run along it.
It does two other things worth knowing about. At the rakes — the sloped edges that run from eave to ridge — drip edge installed over the underlayment helps hold the edge of the roof system down in wind. And along the entire perimeter, it covers the gap between the roof deck edge and the first course of shingles, which would otherwise be an entry point for insects and windblown rain.
Installation order — why it's easy to get wrong
The sequence of drip edge and underlayment installation is different at the eaves versus the rakes, and confusing the two creates a leak path.
At the eaves, drip edge goes down first, directly on the roof deck. Underlayment then lays on top of it. That way water flowing down the underlayment runs onto the metal and off the edge — not behind it.
At the rakes, the order flips. Underlayment goes on first, then drip edge lays on top. This holds the underlayment's edge down against wind uplift. GAF's installation guidelines spell this out explicitly, and it matches the IRC requirement.
Adjacent pieces of drip edge need to overlap at least 2 inches. Code also requires mechanical fasteners — nails or screws — every 12 inches along the deck.
What to check if your roof is older
Drip edge wasn't always included in reroofing work the way it is now. Code requirements tightened with the 2012 IRC cycle, and some older Texas homes were reroofed before local jurisdictions adopted those provisions. If your home was last reroofed more than 10-15 years ago, it's worth asking whether drip edge was installed — and whether what's there is in good shape. Every residential roofing job we do in Amarillo includes new drip edge as part of the standard scope.
Signs of missing or failed drip edge usually show up at the fascia first: paint peeling from the inside edge of the fascia board, soft spots when you press on it, or rust streaks on the siding below the gutter line. If your gutters are pulling away from the fascia, that's often rot from years of water running the wrong direction.
Why this matters more in Amarillo
Potter County sits in Hail Alley — the stretch of the Southern Plains where dry air from New Mexico and Gulf moisture collide. The area averages 8 to 12 hailstorms per year, and since 2000 has logged 131 hail days. Wind is a constant factor too, with average speeds of 14.3 mph. The largest recorded hailstone near Amarillo measured 4.25 inches — softball-sized — in May 2019.
Hail and high-wind events stress every component of the roof edge, not just the shingles. A drip edge that's been dented by hail, lifted by wind, or corroded through years of moisture contact is no longer doing its job. After a significant storm, it's worth having the perimeter flashing inspected along with the shingles — a gap or lifted section at the eave becomes a fast path for windblown rain to get under the roof system.
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Frequently Asked Questions
Is drip edge required by code?
Yes. IRC Section R905.2.8.5 requires drip edge at all eaves and rakes on asphalt shingle roofs. It must extend at least 1/4 inch below the roof sheathing, reach 2 inches back up the deck, and be fastened every 12 inches. Texas building departments adopt the IRC, so skipping it isn't a code-compliant option.
Does drip edge go over or under the underlayment?
Both, depending on where you are on the roof. At the eaves, drip edge goes under the underlayment so water flows over the metal and off. At the rakes, it goes on top of the underlayment to resist wind uplift. The installation sequence matters — swapping the order creates a pathway for water to get behind the fascia.
What is drip edge made of?
Most residential drip edge is galvanized steel or aluminum. Aluminum is lighter and resists rust without coatings; galvanized steel is stiffer and holds its shape better in high-wind areas. Copper is an option on high-end projects. Whatever material is used, code requires it to be corrosion-resistant.
How long does drip edge last?
Aluminum and galvanized steel drip edge typically outlasts the shingles above it when installed correctly. Problems usually show up at joints where adjacent sections weren't overlapped enough (code requires 2-inch overlaps) or where contractors reused old drip edge during a reroof.
What happens if drip edge is missing or wrong?
Without drip edge, water runs down the fascia instead of dripping clear of it. Over time that produces rot behind the gutter, fascia deterioration, and sometimes soffit damage. In a hail-prone market like the Texas Panhandle, a missing or damaged drip edge can also become a wind-entry point along the roof edge.
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