Category Archives: flexible flue liner

Do you need to line your chimney? Part 2

Do you need to line your chimney?

Building regulations do not say that it is essential to fit a flexible flue liner. If a chimney can be proven to be in good order then you do not have to fit a flexible flue liner.

ChimFit say that to really try and put you off from choosing not to fit a flexible flue liner. A wood burning stove that is designed to work with a 6 inch flue will not perform as well if it were attached to a chimney of 11 inch diameter!

With a flexible flue liner fitted properly, insulated (if required) there should be no reason for a wood burning stove not to perform perfectly.

The only time ChimFit may not recommend chimney liners is if the chimney is new.

Possible problems of deciding not to fit a ChimFit recommended flexible flue liner

1. If the chimney is not in good working order then smoke and harmful Carbon Monoxide can travel into your home, this is very dangerous since Carbon monoxide can kill and does kill. Note: that’s why a Carbon monoxide detector in all bedrooms as well as the room with the stove is highly recommended by ChimFit.

2. Hot air and gas rises – cool it down and it will slow its assent, stop altogether or sink. Hot air or gas does not rise well in cold chimney spaces, especially where heat-stealing space or rough surfaces are in the chimney as they steal heat and slow down the deposits that travel with the gases. These deposits, when slowed, form tar and condensation both of which can damage the innards of the chimney. If smoke slows down too much then the flow of said smoke starts to build up and dams underneath, thus the stove begins to burn inefficiently.

Register Plate or Closure Plate?

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A closure plate and a register plate are two different items used for the installation of stoves. A closure plate is used when you have a chimney liner (flexible) the closure plate closes the chimney to be cosmetic, this stops old soot dirt and moisture dropping on the stove and to stop heat disappearing up into the chimney. If the closure plate developed a fault, smoke could NOT enter the room. A closure plate can be made of any non-combustible material. A register plate is used when there is no chimney liner and acts as a barrier to the smoke and fumes in the chimney – it must make a sturdy seal between the room and the chimney and it MUST be made of galvanised or stainless steel (or other non-rusting metal) at least 2mm thick.

A register plate would usually have access doors to allow the sweep to access any chamber above it to remove fallen soot.

Why do closure plates need to be made of metal? That is because if a register plate failed then smoke could enter the room where the stove is burning. (e.g.) if a brick fell from inside of the chimney.

It is uncommon these days that liner are not fitted (although stove flue pipes might be connected directly to pot lined chimneys) and therefore register plates are less common on new installs. Modern wood burners are highly efficient and this means that LESS heat goes up the chimney. It is the heat that gives the draft (hot air rises and the hotter then the faster it rises).

The more efficient the wood burning stove the less heat is wasted up the chimney and the more likely that a liner, will be what the stove requires to function correctly.

What to Know When Installing Flue Liner – Chimfit

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Most of our customers here at chimfit fit their stove and or flue liner themselves. You do not have to use a professional installer if you are DIY savvy and have general competence, If you are installing the wood burning stove into an fireplace and not installing a new chimney liner then the installation is very straightforward. Installing a chimfit flexible chimney liner or complete twin wall flue system is a larger project and may involve ladders/scaffolding if your roof does not have external access, this is since it is needed for the job, is still is however technically straightforward. Our twin wall chimney system simply slots together, no specialist knowledge or skills are required.

If you are thinking of completing the work yourself then you should contact the local council Building Control, they can then inspect the work you have done and sign it off if it is up to standard. Alternatively if the work is done by a professional installer (Which we here at Chimfit recommend) who is accredited by one of the relevant Competent Persons schemes such as HETAS then they can sign off their work themselves.

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Old houses will usually have exposed brick inside the chimney so it is not a legal requirement to line these older chimneys with chimfits liner unless they are broken or leaking, there are often advantages to lining such as increased draw. Installation of a wood burning stove and/or new flue system would not usually have anything to do with the local planning authority. If your property is a Listed Building then permission may or may not be required. If you intend your new chimfit flue pipework to run up the outside of an external wall then depending on the position you may need to check with the local Planning Department.