The hard part is finding the cause, because water can travel a long way before it shows. We check the chimney from the roof and the loft before we quote, so you pay for the repair that actually stops the leak.
Why chimneys leak
- Lead flashing that has split, slipped or pulled out of the mortar joints where the stack meets the roof.
- Worn or missing pointing, letting rain soak into the brickwork.
- Cracked flaunching (the mortar on top of the stack), letting water straight into the stack.
- Open or broken pots on unused flues, letting rain run down the inside.
- Porous or spalled bricks that no longer shed water.
- Earlier repairs with sealant or flashing tape that have failed.
Signs of a chimney leak
- Damp patches or peeling paint on the chimney breast, especially after rain
- Water stains on the ceiling next to the chimney
- Wet timbers or staining in the loft around the stack
- Water, soot stains or a musty smell in the fireplace
- White salty deposits on the brickwork inside
Leak or condensation?
Not every damp chimney breast is a leak. When a fireplace is blocked up and the flue is capped with no ventilation, moist air trapped inside the chimney condenses and soaks into the brickwork. The fix is different: the flue needs venting at the top and the bottom, not more sealing. Telling the two apart is the first thing we check.
Fixing it for good
Most chimney leaks are fixed by renewing the lead flashing, repointing the stack, re-laying the flaunching or capping unused flues with a ventilated cap. Where a stack is unused and in poor condition, taking it down and making good the roof can be cheaper than repairing it, and ends the problem for good.
£ Cost guide
Chimney Leak Repair costs
Every chimney is different, so we price each job individually. These are the things that change the price:
- Access: whether scaffolding is needed to reach the stack safely
- The cause: re-wedging flashing is quicker than renewing it, and a cap costs less than a rebuild
- How much of the stack needs repointing or new flaunching
- Roof covering around the stack and how many tiles or slates need lifting
- Whether internal damp damage needs making good afterwards
Send us photos and we'll give you a clear written quote.
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