Chimney leak repair
A stain beside the chimney can come from several places. Finding the real source is most of the job.
Chimney leaks are common in the Twin Ports. Snow piles up on the uphill side of the chimney, melts on sunny days, refreezes at night, and works its way under flashing and into any open joint. Spring rain then finds the same gaps.
Where does the water get in?
- Flashing. The metal where the roof meets the chimney can lift, rust or lose its sealant. Flashing that's only caulked to the brick face, instead of cut into the mortar joints, is a frequent culprit.
- The crown. Cracks in the crown let water straight down inside the masonry.
- A missing cap. Rain and snow fall right down an open flue.
- The brick and mortar. Old brick and washed-out joints absorb water like a sponge.
- No cricket. A wide chimney on a sloped roof can trap snow and water behind it. A cricket, a small peaked section of roof on the uphill side, sheds it around the chimney.
Signs of a chimney leak
- Ceiling or wall stains next to the chimney
- Damp or musty smell from the fireplace, especially after rain
- Rust on the damper or firebox
- Water in the firebox or at the base of the flue
- Wet or stained framing next to the chimney in the attic
How is a leak fixed?
A good contractor checks the cap, crown, brick and flashing before recommending anything, because sealing one spot while water comes in at another wastes money. Repairs can include new step and counter flashing, a new crown or cap, repointing, a cricket, and a breathable water repellent once the masonry is sound. If roofing has to come off around the chimney, ask whether the roofer or the mason is handling it and who covers the warranty.
The chimney company prices the job after seeing the chimney, usually from the roof and inside the flue. We don't quote prices, and any figure given over the phone before an inspection is only a rough starting point.
Where we connect you with help
Common questions
Why does my chimney only leak in spring?
Snow drifts against the chimney and melts in spring sun, then refreezes. That meltwater finds gaps in flashing and mortar that summer rain might not. Have the flashing and crown checked.
Will a waterproofing sealer stop my chimney leak?
Only if the water is soaking through the brick itself. It won't fix bad flashing, a cracked crown or a missing cap. Fix those first, then consider a breathable repellent.
Related services
- Chimney masonry and tuckpointing
- Chimney crowns and caps
- Chimney liners and relining
- Chimney inspection and sweeping
More background: Duluth chimney guide.
Loose brick, a leaking chimney or a stove you haven't had checked?
Call now and a local chimney company will look at it and quote the work.