Whatever type of wood you use in your fireplace or stove, you’re gong to produce creosote. It’s a natural fact of burning wood; as well as ash and smoke, fireplace owners are also left with this waste material. Creosote can be a danger if left to build up, which is why it is so important wood fireplace and stove owners understand it.
What is creosote?
Creosote is formed when the wood you burn does not combust fully (which is all the time), it’s not possible to burn 100% of the wood efficiently without producing a small amount of debris.
When the oils in the wood do not burn fully, volatiles are released into your chimney; as smoke rises the it cools and the volatiles condense on your chimney’s walls; what’s left is known as creosote.
Creosote starts out as a flaky soot which can be easily cleaned up with a standard brush, if layers form on-top however it can build up to a thick tar which is very hard to clean. Creosote is deposited into your chimney or flue each time you use the appliance.
Why creosote is dangerous
The biggest risk of creosote is a chimney fire, making it among the biggest dangers of using a wood burning appliance. Creosote is highly flammable and presents a serious risk to a chimney if the fire spreads.
The NFPA (National Fire Protection Association) says that failing to remove creosote can cause a fatal fire.
How to remove creosote from the flue
The method used to clear creosote depends on how much there is and how long it has been building up. In the early stages you can use a standard chimney brush to sweep away the flaky soot. For more stubborn residue a specialist drill known as a rotary loop may be used. Some chemical removers can also be used. In serious cases the chimney liner may need to be removed.
To be safe it is best to contact a professional chimney cleaner.
How to reduce creosote build-up
There will always be some residue left behind when you burn your fireplace or stove, but you can limit the amount.
- Always use seasoned firewood – It should be dried out for at least 6 months.
- Allow sufficient airflow – Glass doors and inserts can restrict air.
- Ensure the chimney is sufficiently insulated – If the chimney is outside the home, the difference in temperature can lead to inefficient combustion.
- Burn hot instead of smouldering as this does not burn as completely.
You can help keep your chimney safe with an annual chimney cleaning service which will remove the majority of creosote and minimize the risk of fire.