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What to do if your chimney leaks

A leaking chimney can cause damage throughout your home. We explain how to fix it and what it’ll cost.

A chimney leak is a serious issue that should not be ignored.

If water is leaking through the chimney, the structural integrity of the chimney is being threatened, and it’s crucial you act without delay.

Signs of a leaking chimney

Some of the telltale signs of a leaking chimney include:

  • Water or condensation inside the fireplace
  • The sound of dripping water in the chimney
  • Moisture, leaks, or water staining on the walls or ceilings around the chimney
  • Musty odours coming from the fireplace, especially after it rains
  • Cracks to the interior or exterior masonry

Why is my chimney leaking water?

chimney flashing

There could be a number of reasons why your chimney is leaking water, which is why it’s important to get it properly inspected by a chimney repair specialist.

Some of the most common reasons for a chimney leaking water are:

Chimney flashing

Chimney flashing is the material around the base of the chimney stack, where it joins the roof.

If the flashing becomes damaged or has deteriorated, the seal will no longer be watertight and water will be able to penetrate through.

Chimney flaunching

Chimney flaunching is the top layer of the chimney stack, usually a mortar covering, that holds the chimney pots in place and stops rain and snow from getting into the chimney.

If the flaunching is cracked or broken, it won’t be able to protect your chimney stack as it should. Cracks can often be repaired before they become more of a problem. However, if ignored, parts of the flaunching can break off, and it may need to be completely rebuilt.

Chimney stack

The chimney stack is constantly exposed to the elements, and as such, it’s inevitable that over time, cracks can appear in the brickwork. If this occurs, water will be able to penetrate the chimney stack, causing a leak.

Chimney pointing

Chimney pointing is the mortar joints, in between the bricks of the chimney stack. Over time, this will weather and deteriorate, making it susceptible to leaks if it’s not renewed.

Chimney cap

A chimney cap may not have been installed when your chimney was constructed, but it’s a vital part of the chimney to prevent rainwater from entering.

What to do if your chimney leaks

As a leaking chimney stack can create significant damage to your home, it’s advisable to get your chimney leak repair booked in sooner rather than later.

Use our request a quote feature to receive quotes from certified chimney repair specialists in your area. You can also use our search function below to find reputable tradespeople that your neighbours have used and would recommend.

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What you need to know about chimney flashing repair

chimney flashing being repaired

The thing to understand about chimney flashing is that it covers the gap between the roof tiles and the chimney stack. It must be installed expertly for a watertight seal to be created, preventing water from leaking in through the chimney.

When looking to have your lead flashing repaired or replaced, ask whether your tradesperson has a lead workers’ certificate, i.e. that they have been trained in this specialist skill.

A specialist will also be able to advise whether the existing flashing can be repaired, or whether it must be completely replaced.

How to fix a chimney leak

It goes without saying that working up on the roof is very dangerous.

In addition, unless the cause of the leak is obvious, e.g. a missing chimney cap, you’ll need a chimney inspection to uncover the cause of the leak.

A chimney repair specialist will have the necessary equipment to carry out this work safely and is trained to carry out any repairs to a professional standard. And let’s face it, if water is leaking through your chimney and into your home, you’ll not want anything short of that.

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How much does it cost to repair a chimney leak?

A chimney leak can be caused by a number of different issues, therefore it depends on what’s causing the leak as to how much it’ll cost to fix.

If the chimney leak is due to the deterioration of the chimney pointing, it could cost anywhere from £500 – £1,000 to have it repointed, depending on the extent of the work.

Chimney flashing normally costs in the region of £300 – £400 to replace, depending on the scale of the job.

Key takeaways

  • Common reasons for a leaking chimney include a missing chimney cap, damaged flashing, cracks in the brickwork or the flaunching, or deterioration of the pointing.
  • Water penetrating your chimney can cause water damage and staining to internal walls and ceilings and threaten the structural integrity of your chimney.
  • A professional inspection by a chimney repair specialist will identify the cause of the chimney leak and make sure repair work is carried out to a high standard.
  • The cost to repair a leaking chimney depends on what’s causing the leak. Repointing a chimney normally costs between £500 – £1,000. Repairing chimney flashing can cost between £300 – £400.


How do I stop my chimney from leaking?

The best way to stop your chimney from leaking is to make sure it is inspected regularly and receives any maintenance required. This way, you’ll be alerted to any minor issues before they become bigger, more costly problems.

How much does it cost to fix a leaking chimney?

It depends what’s causing the leak. If the chimney needs to be repointed, it can cost anywhere from £500 – £1,000, depending on the extent of the work. Chimney flashing normally costs in the region of £300 – £400 to replace, depending on the scale of the job.

How do I find a leak in my chimney?

Call in a chimney repair specialist to inspect the chimney fully. They will be able to identify the cause of the leak and carry out the necessary repairs.

What is causing my chimney leak?

A chimney leak can be caused by any number of factors. The chimney flashing, flaunching, or pointing could be in disrepair, or there might be cracks in the chimney stack. A professional chimney specialist will be able to inspect and diagnose the problem.

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