Roof Edge Flashing (Drip Edge) Guide

Roof edge flashing is the bent metal strip that runs along the eaves and rakes of your roof, and skipping it is one of the fastest ways to rot a fascia board. When I tear off an old roof and find no drip edge, I already know what the deck under the first course of shingles looks like: soft, gray, and crumbling.

This guide walks through what roof edge flashing does, the profiles you’ll see at the supply house, how to size and install it, and what it costs. None of it is complicated, but the details decide whether water runs off your house or behind it.

What Roof Edge Flashing Actually Does

Shingles overhang the roof deck by about 3/4 inch. Without a metal edge underneath, water clinging to the underside of that overhang follows the shingle back toward the wood by capillary action — it literally curls under and drips onto the fascia and sheathing instead of into the gutter.

Drip edge solves that with a simple bent lip. The metal kicks the water out past the fascia and directs it into the gutter trough. It also stiffens the shingle overhang so it doesn’t sag or blow up in wind, and it gives the fascia a physical shield against wind-driven rain. The 2018 IRC (Section R905.2.8.5) makes it code on most asphalt shingle roofs for exactly these reasons.

Drip Edge Profiles: Type C, Type D, and Type F

There are three common bends, and the names come from ASTM D3909 shop conventions:

• Type C (L-style): A simple 90-degree angle with a hemmed bottom lip. Cheapest, fine for basic eaves, roughly a 2-inch to 3-inch face.
• Type D (T-style): Has a longer bottom leg that projects out and then kicks down, so water drips well clear of the fascia. This is my default on eaves — the extended lip keeps the wood dry.
• Type F (gutter apron / extended): A long top leg, often 4 to 6 inches, made to reach over the back of a gutter. Use it when you’re re-roofing over existing gutters so runoff lands inside the trough, not behind it.

For most houses I run Type D along the eaves and a hemmed C or D up the rakes. If the gutters stay on during a re-roof, gutter apron (Type F) on the eaves earns its keep.

Materials and Gauges

The three materials you’ll see:

• Aluminum, 0.019 in. to 0.024 in.: The everyday choice. Rust-proof, comes in white, brown, black, and mill finish. A 0.024-in. thickness holds its shape better and doesn’t oil-can. Runs about $9 to $14 per 10-foot stick.
• Galvanized steel, 26 or 24 gauge: Stiffer and cheaper per foot, but it will rust at cut edges over time. Common in older installs and budget jobs.
• Copper, 16 oz.: For slate, standing seam, and high-end work. Beautiful, lasts a century, and costs 8 to 10 times aluminum.

One hard rule: never put bare aluminum drip edge against a copper gutter, or galvanized steel against copper. Dissimilar metals in contact with water corrode galvanically. Match your metals or isolate them.

Where the Underlayment Goes (Eaves vs. Rakes)

This is the detail installers get backwards, so read it twice. The sequence flips depending on which edge you’re on.

• At the eaves (bottom edge): Drip edge goes under the underlayment. Metal first, felt or ice-and-water shield over the top of it. That way any water that gets under the shingles rides over the metal and out.
• At the rakes (gable edge): Drip edge goes over the underlayment. Felt down first, metal on top. Wind-driven rain along a rake needs the metal on the outside to shed it.

In cold climates, I run self-adhering ice-and-water membrane at the eaves lapping over the drip edge, extending at least 24 inches inside the exterior wall line per code.

How to Install Roof Edge Flashing

Here’s the working sequence for an eave run:

1. Snap a chalk line if the fascia is wavy so the metal stays straight to the eye.
2. Set the first stick tight to the deck, bottom lip past the fascia. Nail with 1-1/4 in. roofing nails every 8 to 10 inches, staggered along the top flange, not the face.
3. Overlap each successive piece 2 to 3 inches in the direction water flows. Don’t butt joints — they leak and telegraph gaps.
4. At outside corners, cut and fold a miter or use a factory corner so the lip stays continuous. A snipped, overlapped corner sheds better than a caulked butt joint.
5. Lay ice-and-water shield or felt over the eave metal, then start shingles with the starter course flush to the drip edge lip.

For rakes, run the metal up from the eave corner so the rake piece laps over the eave piece — again, always lapping downhill.

Common Mistakes I See

Nailing through the vertical face instead of the top flange — those nail heads sit right in the water path and rust-stain the fascia. Butting pieces end to end with no overlap. Reversing the eave/rake underlayment order. And the classic: no drip edge at all, with the shingles overhanging into thin air. If your existing roof has stained, spongy fascia, missing edge metal is usually why.

Cost to Add or Replace Drip Edge

Material is cheap; labor is the number that moves. Figures for a typical single-story home:

• Aluminum drip edge, material only: $0.90 to $1.40 per linear foot.
• Installed during a re-roof: $2 to $4 per linear foot — it’s rolled into the tear-off labor, so it’s nearly free to add.
• Retrofit onto an existing roof: $3 to $6 per linear foot, because the installer has to lift the first shingle course and slide metal under it.
• Whole-house eave and rake run (about 200 ft.): roughly $400 to $1,200 installed.

If you’re already re-roofing, there is no reason to leave drip edge off — the added cost is a rounding error against the total, and it’s code in most jurisdictions anyway.

How Drip Edge Works With Gutters

The relationship between edge metal and gutters trips up a lot of homeowners. The drip edge lip should extend far enough to drop water inside the front lip of the gutter, not behind it. When a gutter pulls away from the fascia even a half inch, water sneaking behind it rots the fascia board and the gutter’s back flashing.

If you’re re-roofing with gutters already hung, gutter apron (Type F) is the right call — its long top leg reaches over the gutter’s back edge so runoff can’t slip behind. On a fresh gutter install after a new roof, the installer tucks the gutter’s back flange up under the existing drip edge. Either way, the goal is one continuous downhill path from shingle to metal to gutter with no gap for water to jump.

Color, Finish, and Curb Appeal

Drip edge is a visible trim line, so match it to the fascia or the shingle. White drip edge against a dark fascia frames the roof like a pinstripe — sometimes you want that, often you don’t. On most homes I run brown or black to blend, or white to match painted fascia and soffit. Baked-on Kynar finishes hold color far longer than cheap painted stock and won’t chalk after a few summers of UV. Spend the extra dollar a stick on a good finish; you’re looking at this edge every time you pull in the driveway.

Signs Your Existing Drip Edge Is Failing

Walk the perimeter and look for these tells: rust streaks bleeding down the fascia from nail heads, edge metal that’s pulled loose and rattles in wind, gaps at corners where pieces separated, or a wavy shadow line where the metal oil-canned. Soft, discolored fascia and peeling paint at the roof edge almost always trace back to missing or failed drip edge. If you can slide a putty knife behind the first shingle course and hit bare wood instead of metal, there’s no drip edge there at all.

When to Call a Pro

Replacing a short, accessible eave run on a single-story ranch is a reasonable DIY job if you’re comfortable on a ladder and can cut aluminum with tin snips. Once you’re on a two-story rake, a steep pitch, or you’d have to disturb a big field of shingles to retrofit, hand it to a roofer. The metal itself is forgiving; the height and the shingle-lifting are where people get hurt or cause leaks.

Get roof edge flashing right and it disappears — you never think about it again. Get it wrong or skip it, and you’ll be paying for fascia and sheathing repairs long before the shingles wear out.