What flashing actually does
Shingles are great at shedding water downhill across an open field. They're helpless at corners, walls, and holes. Flashing bridges those transitions: thin metal shaped and layered so water flowing down the roof gets carried over the seam and back onto the shingles below.
When flashing is right, those transitions outlast the shingles. When it's wrong (or just old), the most vulnerable points on your roof are protected by the weakest material on it.
How flashing fails
The failure modes we see most on roofs around Damascus, Clackamas, and Happy Valley:
- Cracking: sealant and older mastic-style flashing dry out and split, exactly like the photo above.
- Rust and corrosion: decades of Oregon moisture eventually win against bare steel.
- Pulling away: temperature cycles and settling work chimney and wall flashing loose from the masonry or siding.
- Bad installation: caulk where layered metal should be. Caulk is a sealant, not a flashing system, and it has a service life measured in a few years.
- Storm damage: wind lifts flashing edges, and once bent, metal doesn't reseal itself.
Signs your flashing is the problem
Leaks that show up near chimneys, around skylights, at ceiling corners along exterior walls, or high on a wall inside the house all point toward flashing. So do stains that reappear after a 'fixed' leak comes back, since misdiagnosed flashing leaks are commonly patched at the wrong spot.
From the ground, look for visible gaps between flashing and chimney, rust streaks, or shiny caulk smeared along seams (a sign someone took a shortcut up there).
What a proper flashing repair looks like
A real flashing fix means removing and replacing the failed metal, layered correctly with the shingles and counter-flashed where it meets masonry, not running a new bead of caulk over the old problem. It's detail work, which is exactly why it gets skipped.
If your leak traces to flashing, here's what our repair service covers. For the bigger leak picture, the Roof Leak Guide starts at the beginning.