Flue Types
What type of flue do I have?
Class I
Normally a property older than 1960 will have this type of flue. It will be a brick built chimney, suitable for a solid fuel fire and can be identified by the clay fire back or “chair brick” at the base of the opening. It will have a minimum diameter of 7” (175mm) and will terminate to a clay pot or cowl. The vast majority of fires are suitable for this type of flue.
Class II
There are two main types of this flue:
- An older property where the chimney is unsound will be lined with a 5” (125mm) flexible steel flue lining, which will be sealed at the top and bottom. This will terminate to a gas cowl. This type of flue is not suitable for a solid fuel fire or open basket
- A modern property without a chimney may well have a 5” (125mm) rigid sectional steel flue system. This will terminate through a short length of steel pipe to a gas cowl. This type of flue is not suitable for a solid fuel fire or open basket
Pre-Cast Flue
Most modern properties will have this type of flue. It is a sectional concrete flue block system and can be identified by the starter block or letter box at the base of the opening. This terminates to a purpose made raised ridge tile. This type of flue is not suitable for a solid fuel fire or open basket.
No Chimney or Flue
If you have no chimney or flue, then you have the following options:
- A Power flue, Fanned flue or Turbo flue gas fire
- An Electric fire
- A Balanced flue gas fire
- A Flue-less gas fire (new catalytic converter technology)










































