Do I Need A Flue Liner?

If you have a standard masonry chimney and wish to install a woodburning or multifuel stove, it is highly advisable to fit a stainless steel flexible flue liner with the stove.

Corinium Flue Systems recommends fitting a flue liner for the following reasons;

• Masonry chimneys, particularly in older properties, are likely to have cracks. Without a liner, any fumes from the stove and creosote formed will leak through cracks in the masonry, possibly exiting in other rooms in your house or in your neighbours'.

• Creosote is a tar like substance that is formed when fumes emitted from the stove cool down as they rise. When these gaseous fumes cool down, any substances contained within the fumes condense and are deposited on the inside of the flue or chimney. A flue liner has a smooth inner skin with less surface area for creosote to be deposited onto, whereas in a masonry chimney it is likely to build up in cracks or crevices. Creosote is highly flammable and is often the cause of chimney fires.

• A flue liner is much narrower than a chimney and is the same diameter from top to bottom. This continuous, consistent pathway will allow the flue gases to exit the chimney much quicker, with less chance of deposits. A flue liner's narrow, consistent diameter also means that it will warm up much quicker than a chimney. This results in an improved draw, making it easier to get a fire burning without lots of smoke back into the stove. A flue liner will retain the heat longer than a chimney after the fire has died out, which means it will be easier to start a new fire the morning after the night before.

• A flue liner is generally more straightforward to sweep. Creosote deposits formed will be harder to remove from a large chimney, especially build ups in cracks or crevices.

A question frequently asked is whether the flue should be insulated - this is done by backfilling the chimney around the flue liner. This is not necessary, but can be beneficial if you have a particularly cold chimney i.e. external, very exposed and very large. Normally the warming of the air in the chimney surrounding the liner during burning is sufficient for insulation.

They are also frequently asked whether a flue liner is necessary to comply with building regulations. It does not state in the building regulations that a flue liner has to be fitted with a stove. However, you must be sure that the chimney is in good working condition and has been sufficiently maintained. The majority of installers and retailers will recommend fitting a flue liner; particularly in older properties, as it is safer and more efficient.

We do not advise asking your installer not to fit a flue liner purely on the basis of cost. Once you have made the one off investment, your stove and flue liner, if properly maintained, will last for years. Most stove and flue manufacturers offer a warranty on their products - for example, Corinium offer a ten year warranty on our flue liner, subject to conditions of use.