How often should you sweep your chimney?
We recommend at a very minimum once a year, but depending on what fuel you burn in your stove you may need to do this more often.
Why sweep your chimney?
1. Removing flammable deposits:
Deposits from the smoke rising up your chimney can condense on its surface, the most dangerous is creosote, a black tarry mix of chemicals that is highly flammable and burns at over 1000°C.
Other deposits can include soot which hinders the smoke from rising, allowing it to cool too quickly in the flue and deposit creosote, heavy deposits can block the chimney causing smoke blowback into your room.
2. Removing blockages:
As well as build-ups caused by smoke deposits, even with a cowl on your chimney, debris (leaves, twigs etc...) can still be blown in your chimney and block it. Birds are an issue too, as once they climb into your chimney they can rarely get out and may die in there causing a partial blockage.
3. Checking its condition:
Older chimneys are made from bricks, newer ones are concrete-lined, over time they crack and bits fall off. Metal flues can corrode (depending on material) and can also crack and split. Creosote is acidic and will attack all three types. Your chimney sweep will also check the condition of the chimney and advise you of any safety issues they might find.
How often do I sweep?
Always have your chimney or flue swept before your first fire of the season then get it swept regularly to keep you and your property safe.
- Wood – Once after your last fire of the season (fresh deposits are easier to remove), then again before your first fire of the season (to remove any debris that may have fallen into the chimney). If you are using it a lot then you may want to play safe and have it swept again about halfway through the season.
- Smokeless fuels – At least once a year.
- Bituminous coal (house coal) – It is now illegal for domestic use in most of the UK and is too dangerous to burn in stoves. For open fires still using it, before your first fire of the season then at least every three months whilst in use.
- Oil burners – Once a year.
- Gas fires – Once a year.
Can I sweep my own chimney?
NO unless you are an accredited chimney sweep never try and clean your chimney yourself. A professional, accredited chimney sweep knows what to do and what to look for. DIY attempts can miss vital safety issues and may damage your chimney or flue.
What about DIY chemical cleaners?
There are a range of these available, most are for professional use or require professional application.
There are some DIY chemicals that can be sprayed on firewood before lighting, or sprayed up the flue and are supposed to reduce creosote build-up.
If you are planning on using any DIY chemicals always talk to a professional sweep first and follow their guidance.
These are to be used as well as a sweep, not instead of!
How to guard against chimney fires
Line your chimney:
No matter the condition of your chimney we advise using a chimney liner or flue, these are much better suited for modern wood and multi-fuel burning stoves, safer to use and easier to maintain.
Make sure that your chimney is swept regularly, its structure is safe and well-maintained (crumbling stack, get it repaired before bricks start tumbling down your flue).
You can have a fire without knowing it if it is confined to the upper part of the flue, so carry out a visual inspection of your chimney or flue outlet at least once a week (you can use binoculars for this).
Use the right fuel:
Never use house coal in any stove, the smoke released is highly volatile and apart from the dangers of an explosive flash in your chimney the smoke can catch fire and can burn for up to 30 minutes.
Only use wood in a wood-burning stove, it is not designed to burn anything else. Only use manufacturer recommended smokeless fuels in multi-fuel burning stoves.
Any wood you burn must be dry or seasoned with a moisture content of less than 20%. Wet (green or unseasoned) wood burns inefficiently, is environmentally damaging, and creates condensation leading to creosote build-up in your chimney. It is now illegal in the UK to burn wet wood in domestic stoves.
Never use builders offcuts that contain paint, varnish, glue, preservatives, plastics or foreign bodies such as nails or screws. The chemicals can give off dangerous gases such as cyanide, and sticky particles that cling to your flue. Foreign bodies can damage the inside of your stove.
Lighting your fire
Never light your fire using liquids like petrol, paraffin or oil. As well as releasing toxic chemicals, using flammable liquids can cause explosions. Use kindling as explained in our fire lighting guide.
Never put any paper or other rubbish on your fire once it’s burning, these can create floating embers that could start a chimney fire.