Terra Nova Roofing & ConstructionHow to Repair Roof Flashing Against a Wall
Water stain on the wall below a dormer, a split-level's upper wall, or beside a chimney? Roof-to-wall flashing is one of the most common leak sources we repair in North Jersey. Here's how it's supposed to be built, why caulk doesn't fix it, and how Terra Nova Roofing & Construction repairs it properly.
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Text a photo of where the roof meets the wall to 973-200-1617 and we'll tell you what we see.
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How do you repair roof flashing against a wall?
To repair roof flashing against a wall properly, the roofer removes the bottom course of siding and the shingles along the wall, replaces wet sheathing, runs ice & water barrier up the wall, installs new step flashing — one piece per shingle course — plus a kickout at the bottom, then laps the wall's water barrier and siding back over it. Terra Nova Roofing & Construction does this repair from $950, with a free inspection and photos. Call or text 973-200-1617.
What kinds of roof-to-wall flashing are there?
Where a roof meets a wall, water has to be turned away from the joint. Which flashing does that depends on which way the roof slopes against the wall:
| Flashing | Where it goes | What it does |
|---|---|---|
| Step flashing | Sloped roof running alongside a wall (sidewall) | L-shaped pieces woven in with each shingle course, each one shedding water onto the next shingle |
| Apron / headwall flashing | Top of a roof that dies into a wall | One long L-shaped piece turning up the wall and lapping down over the top shingles |
| Kickout flashing | Bottom of a roof-to-wall joint, at the gutter end | Turns water out into the gutter instead of down the wall |
| Counter flashing | Over step or apron flashing on brick, stone or stucco | Covers the top edge of the base flashing, set into the masonry |
| Flat-roof wall flashing | Where a flat roof turns up a wall or parapet | Membrane run up the wall and terminated under a metal bar or counter flashing |
More on each type: step flashing · headwall flashing · kickout flashing · counter flashing · flat-roof flashing.
How can you tell the flashing against a wall is leaking?
Look for water damage on the wall below or beside the roof joint — inside and outside — especially after wind-driven rain. Common signs:
- A stain on the ceiling or wall right where a lower roof meets an upper wall — at a dormer, a split-level, a garage tied into the house or a second-floor addition.
- Peeling paint, soft trim or rot on the siding just below the bottom of the roof line. That's usually a missing kickout.
- Stains inside a window frame on the wall below the joint.
- Tar, caulk or roof cement smeared along the joint — a sign someone has already tried to patch it.
- No visible metal at the joint at all, with shingles simply butted against the siding.
- Leaks that appear only in storms, not in every gentle rain. Sideways rain hits the wall and finds the gap.
The stain often shows up a few feet from the actual gap, because water runs along the sheathing and framing before it drips. See roof flashing leak repair.
Why don't caulk and tar fix leaking wall flashing?
Because the leak is a layering problem, and sealant can't fix layering — it only covers the surface for a season or two. Properly built wall flashing doesn't rely on any sealant at all. It works like shingles: every upper layer laps over the layer below, so water always runs down and out.
When step flashing is missing, installed as one long piece instead of individual steps, or tucked over the siding's water barrier instead of under it, water is directed into the wall. Smearing caulk on top doesn't change where the water goes once it gets behind. And sealant on a roof joint dries, shrinks and cracks with North Jersey's freeze-thaw cycles, usually within a few seasons.
Sealant has a place — a small bead at the top edge of counter flashing in a masonry joint, for example — but it's the last detail, not the repair. More: roof flashing sealant failure.
How is a roof-to-wall flashing repair done, step by step?
Open the wall
Remove the lowest course or two of siding along the joint, carefully so it can go back on, or replace it if damaged.
Open the roof
Remove the shingles along the wall — usually one to two feet out — and the old flashing.
Fix the wood
Check the roof sheathing and the wall sheathing. Wet or rotted wood is cut out and replaced.
Seal the corner
Run ice & water barrier along the deck and up the wall several inches, so the inside corner is waterproof on its own.
Weave in step flashing
Re-shingle, placing one step flashing piece with each course — overlapping the one below, nailed to the roof only.
Add the kickout
Install a kickout at the bottom so water goes into the gutter, not down the wall.
Lap the wall back over
The wall's housewrap or felt laps over the vertical leg of the flashing, then siding goes back on.
Test and photograph
We check the joint, clean up, and photograph the finished work for you.
The key detail is step 7: the wall's water barrier has to go over the flashing, not behind it. If it's reversed, water gets in no matter how good the metal is. See also sidewall flashing repair and flashing on siding.
Why does a missing kickout flashing rot the wall below?
Without a kickout, all the water running down the roof-to-wall joint pours out at the bottom and runs straight down the face of the wall — and behind the siding. On a split-level, a garage tied into a two-story wall, or a porch roof against the house, that's a lot of water in one spot every storm.
The result is a classic pattern: rotted sheathing and framing in a triangle below the bottom of the roof line, peeling paint, and sometimes a stain inside on the lower floor. It's often found years after the house was built, because the damage is hidden behind siding. A kickout is a small part — a bent piece of metal at the bottom of the step flashing — but it's one of the most important. Guide: kickout flashing repair.
What about flashing against brick, stone or stucco walls?
On masonry walls, step or apron flashing goes on the roof as usual, and a separate counter flashing is set into the wall to cover its top edge. Masonry can't be lapped over flashing the way siding can, so the counter flashing does that job.
- Brick and block — we cut a groove (reglet) into a mortar joint, insert the counter flashing, and seal the groove. On brick walls and chimneys, the counter flashing is often stepped to follow the mortar lines.
- Stone — irregular faces need the counter flashing scribed to fit, or a cut reglet into a joint.
- Stucco — this is the hardest. Correct repair usually means opening the stucco along the joint to reach the flashing and the paper behind it, then patching the stucco after. Surface caulking alone rarely holds.
The same approach applies at chimneys: chimney counter flashing repair.
How much does roof-to-wall flashing repair cost?
A small roof-to-wall flashing fix starts from $650; most full wall flashing repairs fall under standard roof repair, from $950. The exact price comes in writing after a free inspection:
| Situation | Starting price | What moves it |
|---|---|---|
| Short joint, new kickout, siding comes off easily | From $650 | Length of the joint, siding type |
| Full sidewall or headwall re-flashing | From $950 | Length, roof pitch, number of courses, siding or masonry |
| Active leak needing a temporary dry-in first | From $1,500 | Weather, size of the opening |
| Rotted roof or wall sheathing | Extra | How far the water has spread — shown to you before replacing |
Brick, stone and stucco walls take more time than vinyl or wood siding. More: how much flashing repair costs.
Can you repair wall flashing yourself?
A handy homeowner can sometimes add a missing kickout on a one-story roof, but a full roof-to-wall repair usually isn't a good DIY job. It means removing siding without breaking it, lifting shingles without tearing the ones you'll keep, working on a pitched roof against a wall, and getting the layering exactly right. Done backwards, it makes the leak worse.
If you want to look first, stay on the ground or a properly set ladder and check for: visible metal at the joint, a kickout at the bottom, and any soft or stained siding below. Photos of those three things tell us a lot. Never walk a wet roof. If there's an active leak, see emergency roof leak repair.
Should wall flashing be fixed now or with a new roof?
Fix it now if the roof has years left; fold it into the replacement if the roof is near the end of its life. Every Terra Nova roof replacement includes new step, apron, counter and kickout flashing — we never reuse old wall flashing under new shingles — along with synthetic underlayment and ice & water barrier at the walls, eaves and valleys. Most replacements take 1–3 days.
If the roof is older and you're seeing leaks in more than one place, we'll price both a repair and a replacement in writing. See repair vs. replacement, roof replacement and roof repair in New Jersey.
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Get a Free Flashing Inspection
Tell us where the roof meets the wall and send a photo if you can. We'll inspect it, show you photos and give you the exact price in writing.
Why homeowners call us about wall flashing
- A stain below a dormer or upper wall
- Rotted siding at the bottom of a roof line
- Leaks only in wind-driven rain
- Tar and caulk that keep failing
- A split-level or addition that's always leaked
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Roof-to-Wall Flashing Questions
Can roof flashing against a wall be repaired without removing siding?
Not properly in most cases. The wall's water barrier and siding must lap over the flashing, so the bottom course of siding usually has to come off and go back on.
How much does wall flashing repair cost?
Small fixes start from $650 and most full wall flashing repairs from $950. Rotted sheathing is extra. You get the exact price in writing after a free inspection.
How long does a wall flashing repair take?
Most take a few hours to a day. Long joints, steep roofs, masonry or stucco walls take longer.
Is caulking the joint good enough?
No. Caulk covers the surface but doesn't fix the layering that sends water into the wall, and it cracks within a few seasons.
What is kickout flashing?
It's a bent piece of metal at the bottom of a roof-to-wall joint that turns water into the gutter instead of down the wall. Without it, the wall below often rots.
Do I need to be home for the repair?
Not necessarily. We need access to the roof and the wall. We'll send photos of what we found and the finished work.
What if it rains during the repair?
We don't leave the joint open. If rain is coming, the roof and wall are covered with a tarp or temporary dry-in until we finish.
Will insurance pay for a flashing repair?
Sometimes, if a covered event like a windstorm damaged it. Flashing that was installed wrong or wore out usually isn't covered. The insurer decides.
What does the free estimate include?
An inspection of the joint, roof and, if needed, the attic; photos; and a written estimate with the exact price and what it includes.
Do you match the siding when it goes back on?
We reinstall the existing siding where it comes off cleanly. If pieces are damaged, we'll match as closely as possible and tell you beforehand.
Is financing available?
Financing is available for larger projects like a roof replacement. Options and terms depend on the project and approval.
Are you licensed and insured?
Yes. Licensed and insured, NJ Lic. #13VH13824700, locally owned in Garfield, NJ. Hablamos español.
Updated November 2026 by the Terra Nova Roofing & Construction team, Garfield, NJ • NJ Lic. #13VH13824700