Chimney Care

Damaged chimneys – stacks, liners and flues

The two main reasons for damage to a chimney stack are:

  • A chimney fire

  • Weathering with age

A mixture of external weathering and internal corrosion from soot means that your chimney will need regular maintenance. Your local Guild sweep will make a number of checks prior to starting the job and visually inspecting the stack is just one. In the event of damage they will also be able to offer appropriate repair advice.

Damage to the chimney stack and flue can affect he performance of your chimney and reduce its ability to remove harmful gases. You can lower the risk of damage to your property by keeping on top of your repairs and having your chimney swept regularly be a Guild Sweep. In the event of a chimney fire we recommend that an integrity test and camera survey is carried out on the installation and flue before it is used again.

Chimney terminals

The terminal, or top of your chimney, is a very important part of the system. If a terminal is wrong or fitted incorrectly then it may interfere with the passage of poisonous gases. A professional Guild Sweep will be able to advise on the correct material, design and fit of the terminal to ensure maximum safety at all times.

Landlord and tenant advice

A chimney fire can result in thousands of pounds worth of damage to a property and landlords also risk a claim from their tenants. Current legislation states that the landlord has a duty of care towards the tenant to keep the property safe from unnecessary fire risks. This includes aspects such as blocked flues that could result in harm towards the tenant, in the event of a fire or carbon monoxide poisoning. We therefore recommend that the landlord takes responsibility for having the chimney swept regularly and maintained. The tenant remains responsible for using the appliance as instructed, burning the correct fuels and reporting any problems to the landlord.

Protect yourself against carbon monoxide poisoning

Carbon Monoxide (CO) is a poisonous gas which is given off when burning solid fuel. Normally, CO gas passes harmlessly out of the top of the chimney, however, if the chimney is blocked or leaky, the appliance is faulty or if the ventilation to the fire is inadequate, CO gas may enter your property. You can’t see, taste or smell it, but CO gas can kill quickly and without warning. It is therefore important that you take steps to remove the risk to yourself and your family:

We therefore recommend that you:

  • Ensure your chimney is swept regularly by a trained and registered Guild Sweep.

  • Ensure that the fire has adequate ventilation at all times. Don’t block vents.

  • Use only HETAS registered installers for fitting solid fuel appliances

  • Fit a Carbon Monoxide Alarm in your property.

Every time your chimney is swept by a Guild Sweep, they will make a number of checks to your chimney and appliance including checking for adequate ventilation and can offer advice on CO alarms. For further information on Carbon Monoxide speak to your Guild Sweep or visit which has an excellent section explaining Carbon Monoxide poisoning in more detail.

Ventilation requirements

It is very important to let your solid fuel appliance breath properly with adequate ventilation from an outside source. A lack of ventilation can be dangerous which can lead to poor burning, low heat production and reduced efficiency.

Open Fires

An open fire, with or without a boiler, should include an air opening of at least 50% of the throat opening area, the narrowest part of the fireplace – Ask your Guild Sweep for advice. This is typically 5 inch diameter and provides ventilation to the room from outside the building.

Stoves and Room Heaters

If the house was built before 2008 than a vent is usually only required of the appliance is larger than 5kW. The vent would need to be 550mm2 per kW over 5kW. This means that an 8kW stove would require a vent of 1650mm2.

If the house was built after 2008 then a 550m2 per kW vent needs to be fitted. For instance, an 8kW stove would need ventilation of 4400mm2.

It is sometimes necessary to fit a vent in an older property with a 5kW stove if there is not sufficient air flow. Your Guild Sweep will be able to advise you on your ventilation requirements.

Correct fuel, correct use

Burning the correct fuel on your solid fuel appliance will help you to get the most efficient use from it. Similarly, it is important to check that your liner/chimney is suitable for the type of fuel you are using. Using the wrong type of fuel for a liner will reduce is life considerably due to increase corrosion.

Using the correct fuel for your appliance will also dramatically reduce the amount of soot or tar that builds up and will decrease the risk of a chimney fire.

It is vital that coal and smokeless fuels are not used on dedicated wood burners as this will lead to a greater build-up of soot and damage to the appliance. Suitable kiln dried wood can be used in multi-fuel stoves and we recommend that you look for a product with a moisture content of less than 20%. With wood fuels it is important to store it correctly to improve aeration and keep moisture levels low. If storing logs outside, use a purpose built log store or at the very least raise the logs off the ground on pallets and simply cover the top (but not the sides) of the pile to protect from rainfall.

Wood burning and air quality see how to get the best out of your stove Click here

Any questions?

Chimney Matters

Blacksmiths Lane, Rede
Bury St Edmunds

IP29 4BE

Tel: 01284 789663

Mobile: 07767 864127


Find Chimney Matters on the Find a Sweep, Guild of Master Sweeps and HETAS websites


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