How to clean a chimney, where to find the right chimney sweep, and signs it needs sweeping for winter

While the idea of a chimney sweep may seem old-fashioned and reminiscent of ‘Mary Poppins’, knowing how to clean a chimney is an essential part of home ownership. 

Yes, we think you’ll agree that there’s nothing better than sitting in front of your living room fireplace as the nights get darker and the days get colder. The crackle of a roaring fire and the heat it gives off can really turn a house into a home - not to mention the fact that it can lower your gas bill. 

But it’s important to understand that an open fire is so much more than a warming winter decoration. It’s crucial that homeowners clean a chimney properly, or they risk suffering the consequences. And that’s why we’ve put together the ultimate chimney guide. From how to clean a chimney to knowing how to find the perfect chimney sweep, we’ve covered it all. 

Why you should sweep your chimney

There are two main reasons to sweep your chimney – to ensure your fire burns efficiently, and to reduce the risk of a chimney fire. Regular sweeping removes any build up of flammable materials, such as coal soot or wood tar, which can otherwise build up to the level where they ignite.

Thankfully, chimney fires are far less common than they used to be, with 2,608 occurring from 1 April 2021 to 31 March 2022. Government fire statistics show that the number of chimney fires has fallen 66% over the previous decade, and account for less than 2% of total fires in the last year.  

That said, 2,608 fires is still significant, and with more of us turning to wood burning for heat to save money, the trend could reverse. 

HETAS is a non-profit organisation that accredits approved heating installers, retailers and chimney sweeps, as well as appliances and fuels. Its CEO, Bruce Allen, says, ‘Over the last ten years, the number of chimney fires has decreased, but there is still more we can do to take action against the risk of chimney fires. It’s really important that we continue to help people find and use approved professionals for sweeping and maintaining their appliances and chimneys efficiently and safely.’

How do you find the right chimney sweep?

Although there are many people out there who could clean your chimney for you, that doesn’t mean that they should. To find the right chimney sweep, you need to consider a few things.

Property expert Gregory Smith at PriceYourJob.co.uk says, ‘It is recommended that you look for a chimney sweep that is registered with HETAS. This ensures the sweeper has had proper training and knows the correct safety standards in place.’ But that’s not all you need to research. 

‘It is also a good idea to check whether your chimney sweep has liability insurance. This means that you won’t be held liable if anything were to go wrong during the process, and you will be insured against any potential damages.’

Of course, as with hiring any tradesperson, it’s also a good idea to consider their reputation. If possible, read online reviews from previous customers. And while word-of-mouth recommendations from friends and family are helpful, you should always do your own research to ensure it’s the right fit for you.

How to clean a chimney

Step-by-step guide

1. Inspect your chimney

Before you call your sweep, inspect your chimney and flue from both the inside and outside of the house. Look for any signs or nesting birds and animals, and for any cracks or damage that could be cause for concern. It’s helpful to alert your chimney sweep to anything you’ve spotted. 

2. Identify your flue liner

If you have a modern chimney or renovated house, your chimney may have been fitted with flexible metal tube liner that help to channel smoke and particles through the stack and out into the open. 

If you have a liner, it’s worth letting your sweep know before they come to clean it, since the job may need to be done in a different way.

3. Book a chimney sweep

‘HETAS operates a chimney sweeps’ approval scheme that ensures all approved sweeps are trained and experienced in their work,’ says Bruce Allen. 

The scheme works with both chimney sweep trade organisations and independent sweeps, and the list is comprehensive. To find a sweep in your area, visit HETAS online or call 01684 278170.  

4. Declutter your fireplace

‘It’s helpful to a chimney sweep if you do a little prep work to make sure a professional has a clean and safe space to work,’ says Colin Burton. ‘Clear the mantelpiece and fireplace of any ornaments or valuables as it can be quite a messy job. You may even want to cover furniture just in case, especially if it hasn’t been swept for a while – I say this speaking from experience!’

The vast majority of chimney sweeps will bring their own protective coverings and do their utmost to ensure your decor isn’t damaged.

5. Remove any leftover wood or fuel, and piles of ash

Make sure you’re wearing clothes you don’t mind getting dirty for this job, and protect the surrounding areas with sheets.

Fireplace specialist Glowing Embers recommends that you ‘start by moving any large pieces of debris with your hands and placing them straight in your bin bags. If you don’t want to get too dirty, use a dustpan and brush to help you move some of the debris. When you’ve got rid of the big pieces, use a handheld vacuum cleaner to help with the smallest bits.’

6. Let the sweep do their job

Now it’s over to your chimney sweep. A standard sweep (known as a Level 1 inspection and sweep) will involve them checking your chimney from the inside using a torch and perhaps a camera. 

They'll look for signs of obstructions like birds nests, and any build up of creosote and soot. They won’t need to access your roof. They may alert you to any signs of damage, which will need to be dealt with separately by a professional. 

Then, they will prep the space for cleaning, and use poles, brushes and a vacuum to clear your chimney. 

7. It’s your turn to tackle the brickwork and grate

Once the chimney is swept, you can finish the job. Remove the fire grate and clean it with soapy water. Glowing Embers suggests that you clean the brick surrounds with ‘a solution made from cream of tartar and water. If you have a soot stain that’s particularly stubborn, you may need to use a specialist cleaning solution, like a trisodium phosphate cleaner.’ We like the Intralabs Trisodium Phosphate Industrial Cleaner, £7.29, Amazon.

If you do use trisodium phosphate, also known as TSP, be mindful that it is toxic and can be dangerous if used incorrectly. Always wear protective gloves, goggles, and make sure your arms and legs are fully covered. Prepare using the instructions on the packaging. 

6 signs your chimney needs sweeping

Aside from knowing its time for your annual or bi-annual sweep, there are extra signs that your chimney needs sweeping sooner rather than later. ‘If you’re not sure when you last had it checked, there are some “smoke signals”, so to speak, to look out for,’ says chimeny expert Colin Burton. 

‘If the fireplace surround is turning black, soot’s dropping down into the chimney, or there are any unpleasant lingering smells, it’s a warning sign to get your chimney swept.’

Here’s a more comprehensive list:

1. You suspect that birds or other animals are nesting in your chimney. You might spot birds gather at your chimney stack or hear regular scratching noises.
2. Soot is blowing into the room or falling back down the chimney into your hearth.
3. You struggle to keep your fire lit or it doesn’t burn as strongly as usual. This is called ‘bad drafting’.
4. There is a bad, creosote or tar-like smell – even if the fire isn’t lit.
5. You can see very dark smoke coming out of the chimney.
6. Your fire surround has turned black with soot.

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