Chimney flashing repair at the joint between brick and roof
Chimney flashing repair rebuilds the metal seal where a chimney passes through the roof: step pieces woven into the shingles and counter-flashing cut into the mortar above them. From 227 Union Street we fix leaking, tarred-over and corroded flashing on houses across New Bedford, and out to Fairhaven, Acushnet and Dartmouth, after checking every side of the stack.
Why roof-line leaks follow certain storms here
Flashing sits where two moving structures meet, and coastal weather finds that joint quickly. Three local patterns come up again and again.
Leaks that appear only in some storms
Coastal storms often blow hard from one direction for hours. If water shows up only in certain storms, the flashing or mortar on the side of the chimney facing that wind is the first place to look.
Sealant on 1970s roofs
Dartmouth and Acushnet have many houses from the 1960s and 1970s. On those, original flashing details are now around 50 years old, and caulk or roofing cement smeared over them dried out long ago.
Snow piled behind wide stacks
A broad chimney with no cricket on its uphill side catches snow and meltwater after a nor’easter. That pocket stays wet longest, freezes overnight and is where many winter leaks begin.
Housing ages, heating fuels and storm history come from the sourced notes on our community pages: New Bedford, Dartmouth, Fairhaven, Acushnet.
Rebuilding the seal around the chimney
A leak at the roof line often comes from just one face of the stack, so every side is examined before anything is pulled up.
Check all four faces
The front apron, the step pieces down each side, the back pan or cricket, the counter-flashing above them, the nearby shingles and the mortar joints are each looked at and photographed.
Strip out the shortcuts
Layers of tar, caulk and roofing cement, corroded sheet metal and counter-flashing that has pulled loose from the brick are removed back to clean material.
Weave in new step flashing
Individual L-shaped pieces are laid in with each shingle course up both sides, so every piece laps over the one below and sheds water downhill.
Cut in the counter-flashing
A groove is cut into a mortar joint and the upper layer of metal is set into it and bent down over the step pieces, letting the roof and chimney move without opening a gap.
Build a cricket where it is needed
Behind a wide chimney, a small peaked diverter is framed and flashed so snow and runoff split around the stack instead of piling against it.
Repoint the joints that hold the metal
Mortar joints around the counter-flashing are repointed so the metal stays locked in and the brick around it stops taking in water.
Flashing work disturbs the shingles right around the chimney; if the roof is near the end of its life, it can make sense to coordinate with your roofer.
On houses close to salt water, longer-lasting flashing metals are usually worth discussing before the work starts.
Signs the roof-line seal has let go
Some of these show indoors; others you can see from the ground, or better with binoculars.
- A stain that grows in driving rainA ceiling or wall stain beside the chimney that spreads in wind-driven storms or during snowmelt usually points here.
- Black tar around the baseRoofing cement smeared over the metal means earlier leaks were patched rather than repaired.
- Metal lifting off the brickCounter-flashing bent outward or pulled from its mortar joint leaves an opening for rain.
- Rust or pinholesSteel flashing on chimneys exposed to salt air corrodes and can rust through in spots.
- Damp wood in the atticDarkened rafters or roof sheathing right next to the chimney show where water has been entering.
- Ice dams on the uphill sideIce building up behind the chimney in winter shows water collecting at the weakest part of the seal.
Flashing, or a leak from somewhere else?
Flashing repair is the right call when water gets in at the joint between chimney and roof. When stains appear but the entry point is unclear, a leak diagnosis comes first.
Ask for flashing repair when
- Water shows up at the base of the chimney inside
- The flashing has been covered in tar or caulk
- Metal at the roof line is loose, bent or rusted
- Ice and snow pile up behind a wide chimney
Ask about a different page when
- You cannot tell where the water enters: Chimney Leak Repair
- Broken concrete across the chimney top: Chimney Crown Repair
- The brick itself soaks up rain: Chimney Waterproofing
What decides how much flashing work is involved
Some roof-line repairs are one side of the chimney; others are a full rebuild with a cricket. These factors set the scope.
- Width of the chimney
- A wider stack takes more step and counter-flashing, and past a certain width it usually needs a cricket behind it.
- Roofing material and slope
- Asphalt shingles, slate and metal roofs each need their own flashing details, and a steep slope slows the work.
- Shingles next to the stack
- Brittle or broken shingles around the chimney may need replacing so the new flashing has something sound to weave into.
- Mortar that holds the metal
- Eroded joints where the counter-flashing sits need repointing before new metal can be set securely.
- Years of patching
- Peeling away several generations of tar and sealant from past repairs takes extra time before new work can begin.
No price list on this site, on purpose. Two chimneys that sound the same over the phone rarely are. Once someone from the New Bedford office has looked at yours, you get the scope in writing and decide from there.
More frames of this kind of work
Taken on Chimney Champ’s jobs and kept in the company photo library that all our locations draw on. The library holds no job addresses, so no frame here is tied to a street or a town.
See the matching gallery photosPhoto story: One brick chimney, photographed from every side
Flashing questions homeowners bring us
Why not just put more sealant on it?
Sealant can stop water for a season or two, but sun, cold and the movement between roof and chimney dry it out and crack it. Properly lapped step and counter-flashing keeps water out by shape and overlap, so it does not depend on caulk to work.
What exactly is a cricket?
It is a small peaked structure built on the roof behind a wide chimney and flashed like a miniature roof of its own. It splits the water and snow sliding down the roof and steers them around the sides of the stack instead of letting them sit against its back.
I am getting a new roof. Should the flashing be replaced too?
It should at least be inspected, and in most cases replaced, because old flashing rarely comes through a tear-off in good shape. Doing the chimney flashing in step with the roofer means the shingles and metal around the stack are laid together in the right order.
Do you replace whole roofs?
No. We work on the flashing and the shingles immediately around the chimney as part of that repair. A roof that needs larger repairs or replacement is a roofer’s job, and if we see signs of that, we point them out with photos.
Why does it only leak in winter?
Snow trapped behind a chimney melts on sunny afternoons and refreezes at night. That meltwater can back up under flashing that handles ordinary rain without trouble. Correctly lapped metal, and a cricket on a wide chimney, are the usual answers.
Booking, hours and general chimney questions are on the main FAQ; how a visit runs is on what to expect.
Often looked at alongside
- Chimney Leak RepairTracing water to the crown, cap, flashing, brick or flue where it enters, then repairing that source.
- Chimney Crown RepairSealing, patching or recasting the concrete slab on top of the chimney so rain runs off the stack.
- Chimney Masonry Repair and TuckpointingCutting out failed mortar, repacking the joints with a mix suited to the brick, and replacing damaged bricks.
- Chimney WaterproofingA breathable repellent soaked into sound, repaired chimney brick so it takes up less rain and still dries out.
Background reading
- 6 minAfter a Coastal Storm: How to Check Your Chimney SafelyAfter a nor’easter or hurricane: what to look for from the ground, what not to do, and when a chimney needs inspecting before the next fire.
- 6 minSalt Air, Wind and Coastal Chimneys: What the South Coast Does to Masonry and MetalWind off the water drives rain into masonry and salt into metal. What that means for caps, flashing, crowns and mortar near the coast.
- MapThe four places we coverNew Bedford · Dartmouth · Fairhaven · Acushnet, all from one office downtown.