A Guide to Chimney and Flue Types

When it comes to choosing a new fire for your home it may not be as straightforward as installing the one you like. Ahead of picking the style, it is important that you first determine the type of fireplace that will be suitable for your property. Essentially this comes down to the type of chimney and flue your home has as choosing a fireplace isn’t a one size fits all approach. Having a survey completed by a Gas Safe registered engineer could help to whittle down the options available to you.
Perhaps you’ve just moved in or you’ve been in a property some time and want to change the fireplace. Either way, this brief guide should provide an overview of information to get you in the right direction.

Chimney Types

The style and size of a chimney can really influence the type of fireplace you will end up with and so it is an important first step to know what you are dealing with before making any decisions.
 

Traditional Chimneys (Class 1)

Typically these are found on older properties and they tend to be the traditional brick chimney style. For the most part their purpose was to facilitate an open fire and they would require natural circulation to take the waste gases away from the fireplace.
For homes with a Class 1 Chimney there doesn’t tend to be many restrictions on the type of fireplace but it is important that the chamber itself has enough room to house the fireplace. It may be that a traditional chimney requires a liner as it may not be sealed depending on the age of the property.
 

Prefabricated Flues (Class 2)

This kind of chimney/flue may be found on an old property in circumstances where the chimney has been fitted with a steel flue liner. A pre-fab flue could also be found on a newer home which has a built-in steel flue.
 
Homes with prefabricated flues are easily identifiable by the metal cowl on the roof. The flue itself is comprised of metal flue pipes which interlock.
 
It is possible to have a gas, gel or electric fireplace with a pre-fabricated flue however they aren’t designed to handle solid fuel fires.
In many situations the diameter size of the flue has an influence on the type of fireplace, for instance 7 inches or more will require a Class 1 fire and 5 inches will need require a Class 2 flue.
 

Pre-cast flues

A much more common feature of new properties is to have a pre-cast flue. This is a shallower concrete structure that is built within the interior house walls and can be noticeable on the roof via a small ridge vent. Class 2 fires or an electric fire are really the only compatible options here.
 

No Chimney

If a property doesn’t have a chimney it doesn’t necessarily mean that a fireplace isn’t an option. While an electric fire is always an option as they don’t require a chimney at all there are other options too such as:

• Flueless Gas Fires – as the name suggests these don’t require any flue and a catalytic converter is built in and removes harmful fumes. There are some restrictions on the size of the room and also a 100cm2 ventilation brick also needs to be installed on an external wall.
• Balanced Flue Gas Fires/Closed Combustion Gas Fire – these fires use two pipes – one to extract fumes away and one to supply air to aid combustion. They need to be installed in rooms with an external wall.
• Power Flue Gas Fires – this type of fire has a fan which helps extract the fumes. They require a power source as well as an external wall in order to be installed successfully.

 
Making a Final Decision
Matching your dream fireplace to the type of flue you have might seem like a tricky exercise but the best place to start is to look at our full range of fireplaces and take things from there. We have a wide range of options so we’re sure to have something that suits your home requirements and the style and type you like.
Our team of experts can also help you to decide which are the best options for you based on their wealth of knowledge and experience in fireplace construction and design. Contact us or call in store today!