What should you do when a chimney is leaking inside the house?
Short answer. When a chimney leaks inside the house, protect the area, photograph the water, and note where it appears and in what kind of rain, because the location points to the cause. Water on the ceiling or wall beside the chimney usually means flashing or a missing cricket, water in the firebox points to the cap or crown, and damp stains that appear in cold weather without rain may be condensation from a gas appliance flue.
Right away
- Catch the water and move furniture and rugs.
- If a ceiling is bulging with water, puncture it at the low point over a bucket so it does not collapse.
- Photograph the stains inside and out, with dates.
- Hold off on using the fireplace until a professional checks it, since water can damage the firebox and liner.
What the location tells you
- Ceiling or wall next to the chimney: step flashing, counterflashing, or water ponding behind a chimney with no cricket.
- Inside the firebox or on the damper: missing cap, cracked crown or a damaged flue liner.
- In the attic, down the chimney sides: flashing or brick absorption.
- High on the chimney breast inside: saturated masonry or a crown problem.
The condensation look-alike
Gas furnaces and water heaters venting into an old, unlined or oversized masonry chimney can produce condensation inside the flue. It shows as damp, white, chalky stains on the chimney walls inside the house, often in winter and even without rain. That is a venting problem for a chimney professional or HVAC contractor, often solved with a properly sized liner, not a roof repair.
Insurance
Sudden damage from a storm, such as a limb hitting the chimney or wind tearing the flashing, may be covered. Gradual leaks and wear usually are not, so report storm damage promptly. See chimney leaks and crickets and how insurance treats interior water damage from roof leaks.