Is a crooked chimney in Mississauga and Oakville dangerous, and how much time do I have to rebuild it?
A crooked chimney is a structural hazard. This is no joke - if the chimney has clearly deviated from the vertical, time is working against you.
Why is it dangerous?
- Risk of collapse: A chimney is a huge mass (several hundred kilograms to several tons). A tilt means that the center of gravity is off-axis. Stronger winds, water-soaked bricks, or a shock can cause it to collapse onto the roof, piercing the ceiling or injuring someone below.
- Duct leakage: When a chimney tilts, cracks form inside. Carbon monoxide or sparks can escape through these cracks into the house, posing a risk of attic fire.
- Roof damage: As the chimney “works,” it tears apart the aforementioned flashings, causing immediate and massive flooding of the house.
How much time do you have?
It depends on the cause, but in construction, three scenarios are assumed:
Immediate mode (days/weeks): If the cracks are fresh, wide, and you can see that the chimney is “working” (the gaps are getting bigger), you need to act immediately. Call a chimney sweep or builder to assess whether the chimney needs to be demolished urgently.
One season (months): If the chimney has been crooked “forever” (old construction errors) but is airtight and stable, you theoretically have time until next summer. However, winter is the worst time – frost in the cracks will accelerate the destruction process.
Until the first inspection: Building regulations require annual inspection of chimney flues. When a chimney sweep sees a crooked chimney, they are required to take it out of service, which means no more burning in the stove/fireplace.
What to do about it?
Usually, a crooked chimney cannot be “straightened.” There are two solutions:
- Demolition and rebuilding: Demolish the part above the roof and rebuild it (the safest option).
- Reinforcement with a steel structure: Sometimes steel corsets are used, but this is a temporary solution and often more expensive than replacing the bricks.
My advice: Don't wait until winter. Go up to the attic and see if there are any cracks where the chimney passes through the ceiling. If so, call a professional today.
