Stop
A leaning or separating chimney can collapse; stay clear of the area beneath it, stop using it, and get a professional structural evaluation promptly.
Symptoms
- Chimney visibly tilts away from or toward the house when viewed from a distance
- Growing gap between the chimney and the house siding or roof
- Cracks in brick or mortar concentrated near the base or where it meets the house
Likely causes
- CommonFoundation settling under the chimney separately from the houseChimneys often have their own smaller footing, which can settle at a different rate than the main house foundation.
- CommonDeteriorated mortar and structural connections over decadesOld ties and flashing connecting the chimney to the house can corrode and fail, allowing separation.
- PossibleWater damage weakening the masonry or footing over timeChronic water intrusion softens mortar and can undermine the base.
What to do
- View the chimney from across the street or yard in good light to confirm and measure the extent of any lean.
- Photograph the base and the point where it meets the roof or house from multiple angles.
- Stop using a fireplace connected to a visibly leaning chimney until it's inspected.
- Keep people and pets away from the immediate area beneath a chimney showing significant lean or gapping.
- Get a structural engineer or experienced mason to evaluate the cause and severity.
- Follow their recommended repair plan, which could range from repointing and rebuilding to partial or full chimney reconstruction.
- Don't delay on a leaning chimney, since the problem typically worsens over time rather than stabilizing on its own.
Tools and parts
- Camera
- Level (for reference against a known vertical line)
When to call a pro
Call a structural engineer and an experienced chimney mason as soon as possible.
Safety
Stop
A leaning or separating chimney can collapse; stay clear of the area beneath it, stop using it, and get a professional structural evaluation promptly.