Roof Leaks Around Dormers and Walls: Step Flashing Explained
Some of the worst leaks we find in Murfreesboro are not on the roof at all. They are in the wall below it: a stain at the top of a window on the first floor, siding that is soft at the bottom of a two-story section, a corner of drywall in the garage that keeps bubbling. Every one traces up to the line where a roof slope runs into a vertical wall, and to a piece of bent metal that was either missing, too short, or installed in the wrong order.
What step flashing is
Where a roof slope meets a wall — the side of a dormer, the wall of a two-story section rising above a one-story roof, the side of a chimney — water running down the wall and water running down the roof meet. Step flashing is a series of L-shaped metal pieces, one per shingle course, each lapped over the shingle below and under the shingle above, with the vertical leg running up the wall behind the siding. Water that hits the wall runs down the vertical leg, onto the horizontal leg, and out onto the shingle below. Each piece steps down the roof; that is the name.
Done right, it is close to permanent. Done wrong, it leaks from the first storm, but slowly enough that nobody notices for years.
How it goes wrong on Murfreesboro houses
Most of the city was built between 2005 and 2020 by production crews working fast, and the wall-to-roof junctions are where the speed shows.
Short flashing. Pieces cut too short up the wall, so wind-driven rain gets over the top. Common where a crew ran out of stock and made do.
Continuous flashing instead of step. One long strip of metal caulked along the joint instead of individual stepped pieces. The caulk fails in three summers of Tennessee heat and the strip becomes a gutter aimed into the wall.
No kick-out. At the bottom of the run, where the roof edge meets the wall, a kick-out flashing is supposed to turn the water out into the gutter. Without it, every drop that came down that wall goes behind the siding at the corner. On a two-story house in Blackman or Salem with a one-story garage roof running into the main wall, the missing kick-out shows up as rot at the bottom corner of the wall, usually right where the gutter ends.
Housewrap lapped wrong. The housewrap should lap over the top of the vertical flashing leg so water on the wrap runs out onto the flashing. When the flashing goes on after the wrap, water on the wrap runs behind the flashing. On new builds we see this constantly.
Dormers on the newer farmhouse builds. The 2016–2022 houses south of the city with two or three dormers on the front slope have six wall junctions each, and every one is a chance to get it wrong.
How to spot it from inside
- A stain on the ceiling or the top of a wall directly below where a higher roof section meets the wall
- A stain at the top of a window on a lower floor, under a dormer or a roof-to-wall line
- Siding that is soft, discolored or pulling away at the bottom corner of a two-story wall
- In the attic of a one-story section, a dark line on the framing along the wall it butts into
The leak is often several feet from the stain because the water runs down the inside of the wall before it finds drywall. Our post on tracing a leak from inside covers the attic side.
What the repair involves
A real fix means taking off the siding along the junction and the shingles in the first few courses, then rebuilding it in the right order: underlayment or membrane up the wall, step flashing woven course by course, a kick-out at the bottom, housewrap lapped over the flashing, and siding reinstalled. Caulk is not a repair here; it is a delay.
| Job | Typical Murfreesboro price |
|---|---|
| Step flashing, one wall junction, 8–15 ft | $450 – $1,100 |
| Add a kick-out flashing at one corner | $150 – $350 |
| Dormer, both sides and the front | $700 – $1,600 |
| Chimney step and counter-flashing | $600 – $1,500 |
| Replace rotted sheathing behind the wall | $90 – $150 per sheet, plus siding |
Vinyl siding comes off and goes back easily. Brick is a different job: the flashing has to be counter-flashed into a mortar joint, and the price goes toward the top of each range.
Why builders skipped it
Step flashing takes time, kick-outs are an extra part, and neither is inspected closely on a production build. Tennessee adopted the International Residential Code, which requires flashing at every roof-to-wall intersection, but "flashing" on a fast build often meant one strip and a tube of caulk. The result is a whole generation of houses in Rutherford County where the roof itself is sound and the walls under it are quietly getting wet.
Getting it checked
If your house has a two-story section over a one-story roof, a dormer, or a chimney, and it was built after 2005, the junctions are worth a look before a leak shows up inside. It is part of every roof inspection we do, and a fix now is a $450–$1,100 repair instead of a wall rebuild in three years.
Need roof work in Murfreesboro?
Call for a free estimate. Mon–Sat 7am–7pm.