This is most common in homes built since 2000, where production rooflines have more dormers and wall intersections, and where builder-grade installs tend to repeat the same shortcut across a whole street.
1Why these spots leak
- Step flashing missing or skipped. Each course of shingle along a wall should have its own piece of flashing. Shortcuts use one long piece or caulk. See step flashing at a wall intersection.
- Layers in the wrong order. Flashing has to tuck behind the siding’s weather barrier, not sit on top of it, so water is shed outward.
- No kickout at the bottom. Where a roof edge ends against a wall, a kickout flashing turns water into the gutter. Without it, water runs down the wall.
- Sealant doing flashing’s job. Caulk can hide a missing detail for a few years, then fail.
2How to check
- Look inside firstStains on ceilings or walls below a dormer or where a lower roof meets a taller wall point to the transition above.
- Look at the outside wallStaining, soft spots, or swelling siding below the bottom end of a roof-to-wall line often means a missing kickout.
- Use binoculars on the rooflineLook for heavy caulk instead of metal, gaps along the wall, or flashing you can’t see at all.
- Check in the atticOn a dry day after rain, look for damp wood or stains near the wall or dormer.
- Note when it leaksLeaks only in wind-driven rain from one direction help a roofer find the source.
3Fixing it
Do it yourself
- Document stains with dates and the weather
- Find the installer’s workmanship warranty
- Protect the inside from active leaks
Hire a pro
- Opening the siding and shingles to see the flashing
- Installing step flashing and kickouts correctly
- Checking for rot in the sheathing behind the wall
- Anything at height or on a steep pitch
Sealing over a missing flashing may stop the drip for a while, but water keeps getting into the wall where you can’t see it. Ask for the flashing to be corrected.
4What drives the cost
The price depends on how much siding and shingle has to come off to reach the flashing, how many wall intersections are affected, whether sheathing or framing has rotted, and the height and pitch of the roof. If the installer’s warranty is still live, this may be a workmanship claim. See roof still under the manufacturer warranty.
Talk to a local roofer who will open it up and correct the flashing, not just caulk over it.
877-360-46575Questions
Do I need a roofer or a siding contractor?
Often both trades are involved, since the flashing sits under the siding. Many roofers handle the siding they disturb. Ask.
Why does it only leak in some storms?
Wind-driven rain from one direction pushes water into a weak detail that ordinary rain doesn’t reach.
Is this a warranty issue?
It can be. Flashing is workmanship. If the installer’s warranty is live, contact them in writing first.
Written by Jaylan Jones. I Like To Exterior Services earns a referral fee when a call connects to a contractor. See our business-model disclosure.
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