Chimney and Flue Guide
Class 1 Flue (Brick Chimney)
A brick chimney can be identified by a chimney stack fitted on the roof of a property in the form of either a pot or gas flue terminal. This operates using the natural flow of air through the room and the chimney to remove any products of combustion such as smoke and fumes.
For a class 1 flue, the internal diameter will typically measure 7 inches (180mm) or larger, allowing you to have most types of fires fitted in your home.
Class 2 (Pre-Fabricated Flue)
A pre-fabricated flue is recognised by a metal flue box fitted behind the fire which connects to a series of metal flue pipes installed throughout the property. A gas terminal is fitted on the roof of the property to replicate the same flow of air as a chimney to filter out any fumes or smoke. The internal diameter of the pipe typically measures around 5 inches and as such, is classified as a class 2 flue. However, in some cases the flue may be constructed using a 7 inch pipe which would be recognised as a class 1 flue, so be sure to establish which size you have in your home before selecting a new fireplace.
As most new modern homes are built without a chimney fitted, pre-cast flues offer the ideal solution for homeowners wanting to incorporate a fireplace into their contemporary property. They are constructed using hollow concrete or clay flue blocks which are fitted vertically up through the property to draw fumes from the fireplace to the ridge vent terminal on the roof so the smoke can escape. When choosing a fireplace, it’s important to bear in mind that these flues are typically rather shallow in depth which can limit your choice slightly.
I do not have a chimney in my home, what options are available to me?
These days, most modern homes are built without a chimney, leaving many homeowners thinking that they cannot have a fireplace installed in their home; this is not the case. Even if your property does not feature a chimney, you are still able to incorporate one of the following fireplaces into the room:
- Balanced flue gas fires: as a highly efficient design, balanced flue gas fires are ideal for instantly heating a room and adding a wonderful feature to your home with their elegant glass fronts for superior safety. (Note: for balanced flue installations you require an exterior wall for the flue.)
- Electric fires: available in built-in, inset and freestanding models, this design has a maximum heat output of 2kW