Chimney Flashing Repair in New Jersey
Flashing is the metal that seals the joint between the chimney and the roof. When it fails, water runs into the house along the chimney. We find where the leak starts and fix that joint.
What flashing is
A chimney and a roof move and expand at different rates, so the joint between them cannot be sealed with mortar alone. Flashing is layered metal that bridges the gap. It usually has two parts: step flashing, woven into the roofing along the sides, and counterflashing, set into the mortar joints above it and lapped over the step flashing.
On a chimney that sits on a slope, a small peaked structure called a cricket or saddle behind the chimney diverts water around it. A wider chimney with no cricket collects water and debris on the uphill side.
Signs of a flashing problem
- Water stains on the ceiling or wall near the chimney, especially after rain
- Dripping in the attic around the chimney
- Rust, gaps or lifted metal where the chimney meets the roof
- Roofing tar or caulk smeared along the joint
- Wet insulation or damp framing beside the chimney
- Mortar missing along the line where the metal is set in
Why flashing leaks
- Sealant dries out and cracks, and tar patches rarely last
- The metal corrodes or lifts over time
- The mortar joint that holds the counterflashing breaks down
- The original flashing was installed as one piece or sealed only with caulk
- No cricket on a wide chimney, so water pools behind it
How we approach it
A roof leak near a chimney is not always the flashing. It can also be the crown, the masonry or the cap. We check each of those before recommending work, so you are not paying to fix the wrong joint.
Repair options
| Option | Fits when | Notes |
|---|---|---|
| Re-seal | The metal is sound and a joint has opened | A short-term measure if the cause is not addressed |
| Re-set the counterflashing | Counterflashing is loose or the mortar line has failed | Metal is fitted into a groove cut into the mortar joint and sealed |
| Replace the flashing | The metal is corroded or was installed incorrectly | New step and counterflashing, in a metal suited to the roof and chimney |
| Add a cricket | A wide chimney has no way to shed water behind it | Built into the roof behind the chimney and flashed in |
Where roofing has to be lifted or replaced to flash a chimney properly, we explain what is involved before you decide.
Tracing a leak
Finding the source before fixing it
- Check the flashingMetal, seams, sealant and the mortar line it is set into.
- Rule out the restCrown, cap, brick and mortar above the roof can leak too.
- ExplainWe show you where the water is getting in and what we recommend.
- RepairWe repair or replace the flashing as agreed.
Related services
Chimney Crown Repair
A cracked crown can look like a flashing leak.
Learn moreChimney Repointing
The mortar line holds the counterflashing in place.
Learn moreChimney Inspection
Locate the source of a leak.
Learn moreWe work throughout New Jersey. See our service areas, or browse all services.
Questions
Frequently asked questions
How do I know the leak is from the chimney flashing?
Leaks that show up beside the chimney after rain often point to flashing, but the crown, brick and cap can cause the same stains. Checking each source is the reliable way to tell.
Why not just use roofing tar or caulk?
Tar and caulk can slow a leak for a while, but they dry and crack. Flashing works because the metal is layered to shed water, not because it is sealed.
What is a chimney cricket?
A cricket, or saddle, is a small peaked structure behind a chimney on a sloped roof. It sheds water around the chimney instead of letting it pool.
Is flashing a roofing job or a chimney job?
It is both. The flashing is set into the chimney masonry and woven into the roofing, so the repair has to suit both.
Chimney Academy
Guides that go with this page
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