Drip Edge: The Cheap Part That Prevents Expensive Damage
Drip edge is a strip of bent metal that runs along the edges of a roof. It costs very little, it takes a crew almost no time to install, and its absence is responsible for a surprising amount of rotted timber on otherwise sound houses.
It is also one of the easiest things for a homeowner to check without leaving the ground, which makes it a useful proxy for how carefully the rest of a roof was built.
What it actually does
Water running off a roof does not simply fall. Surface tension pulls it around the edge of whatever it is running over, so water reaching the end of a shingle course will curl back underneath it and travel along the sheathing and fascia rather than dropping cleanly into the gutter.
Drip edge gives that water a hard outward edge to release from. It projects past the fascia, and the lower lip is kicked out so water leaves the metal instead of tracking back. Three consequences follow:
- The fascia board stays dry rather than being wetted every time it rains.
- The edge of the roof sheathing, which is the most vulnerable part, stays protected.
- The gap between the deck edge and the fascia is closed, which keeps out wasps, bats, birds and rodents.
Where it goes, and the detail people get backwards
There are two different edges and the sequence is different on each. This is the part that separates a properly built roof from one that looks finished:
- At the eaves, the horizontal lower edge, drip edge goes under the underlayment. Water on top of the underlayment then runs over the metal and away.
- At the rakes, the sloped edges up the gable, drip edge goes over the underlayment, because here water is being shed sideways off the roof rather than running down toward it.
Get either one the wrong way round and the metal channels water into the assembly instead of out of it. It is a genuinely counterintuitive detail and it is installed backwards more often than you would expect.
And where the gutter fits
The drip edge should extend over the back of the gutter so water is delivered into the trough. If the drip edge stops short of the gutter, water falls into the gap behind it and runs down the fascia. This is why gutters and roofs are best built as one system rather than a year apart.
How to check yours in two minutes
- Stand back and look along the lower edge of the roof. You should see a thin line of metal projecting slightly beyond the fascia, below the first course of shingles.
- Look up the gable edges too. Same thing, metal running along the edge under the shingles.
- If the shingles simply overhang the fascia with nothing beneath them, there is no drip edge.
- Look at the fascia paint. Peeling, staining or dark streaking in a consistent line along the board is the signature of water tracking back.
- Press the fascia gently with a finger somewhere accessible. Softness means the damage is already done.
Why it gets left off
Cost, mostly, and not much of it. On a job priced to win, drip edge is a line that can quietly disappear. It is also invisible from a distance once the roof is on, so nobody notices for years.
The other reason is age. Drip edge was not universally used on older houses, so plenty of roofs built decades ago never had it, and each subsequent re-roof simply reproduced what was there.
It is worth knowing that drip edge at both eaves and rakes has been a residential code requirement in most places for years now. A recent roof without it was very likely not inspected.
Retrofitting it
At the rakes, drip edge can often be added to an existing roof without much disruption, because the metal goes over the underlayment and under the shingle edge.
At the eaves it is harder, because the metal belongs under the underlayment. Doing it properly means lifting the first courses of shingles, which is realistically a job to fold into a roof replacement rather than a standalone repair. If your roof has years left and no eave drip edge, the honest answer is usually to address the fascia, keep the gutters clear, and put it right when the roof is replaced.
Our roofing repair team handles edge metal and fascia work, and drip edge at both eaves and rakes is standard on every roof replacement we do. If you are unsure what is on your roof now, a free roof inspection will tell you, and it is worth naming drip edge specifically when you compare estimates, see how to read a roofing estimate.
Drip edge questions
A strip of bent metal installed along the roof edges. It projects past the fascia and kicks water outward so it drops into the gutter instead of curling back under the shingles and running down the sheathing and fascia board.
Drip edge at eaves and rakes has been a residential code requirement in most jurisdictions for years. Plenty of older roofs do not have it, and a recent roof without it suggests the work was not inspected. Your local building department is the authority for your address.
It depends which edge. At the eaves it goes under the underlayment, so water on top of the underlayment runs over the metal. At the rakes it goes over the underlayment. Getting either backwards channels water into the roof rather than out of it.
Look along the lower and gable edges of the roof for a thin line of metal projecting slightly past the fascia beneath the first shingle course. If the shingles just overhang with nothing under them, it is missing. Peeling paint or dark streaking on the fascia is a supporting sign.
At the rake edges, often yes. At the eaves it is much harder, because the metal belongs underneath the underlayment and the first shingle courses have to be lifted. In practice eave drip edge is usually best added during a roof replacement.
Water tracks back under the shingle edge and wets the fascia and the edge of the roof sheathing every time it rains. Over years that produces rotted fascia, soft sheathing at the perimeter, failing gutter fixings, and an open gap that insects and small animals use to get into the roof space.