The different types of flue liner recommended by Turner Baker
The space inside a chimney is called a flue. The function of the flue is to let out hot flue gas with any harmful chemicals that might be lurking to safely disperse into the atmosphere.
One chimney can contain several flues. That is why you often see houses with one chimney stack with several pots on top. Each individual pot represents one flue.
If you use your flue for an open fire, stove or gas fire then keeping your flue in good working order is very important. Also, those flues in your property that aren’t used any more need to be maintained correctly to avoid degradation.
A flue liner is, in simple terms a tube that fits down inside an existing chimney or even an existing flue in an older property. Flue liners are available in many different materials including stainless steel, pumice, silica polymer and thermosetting resin.
Flue liners are obligatory for new build properties in accordance with building regulations Document J. This means that if you are building a new property with a chimney that you intend to use for heating purposes then it must be suitably lined.
Here is a brief round-up of the different flue liners available:
Furanflex liners from Turner Baker
A relative newcomer to the market is the Furanflex thermosetting resin lining system. In laymen’s terms this refers to a liner that is supplied as a soft malleable material which can be inserted into a chimney and which is then steamed or ‘cured’ into a hardened structure that is resistant to heat and high temperatures.
The Furanflex liner was introduced to the UK in 2010 following a rigorous testing programme to ensure that the product met UK standards. The product has been certified by BBA (British Board of Agrement see website here www.bbacerts.co.uk).
There are many benefits to using a Furanflex lining system. Firstly, the product is installed as a flexible tube. For properties with chimneys that have bends in them – and this is certainly the case for a lot of older properties – this is a great benefit.
The liner can be installed freestanding and it can mould to take the existing shape of the chimney which maximises the cross-sectional area of the flue. Various other lining systems are a set shape and may reduce the size of the flue which in turn affects performance.
Additionally, the Furanflex liner doesn’t adhere itself to the chimney and can therefore be removed if necessary. This makes it an ideal option for heritage properties with listing restrictions which won’t allow for permanent changes to the structure.
The Furanflex lining system is guaranteed for 25 years. In the event of a chimney fire – systems such as stainless steel will need to be replaced before a flue can be used again. The Furanflex system is able to withstand very high temperatures – and in theory should be able to withstand a chimney fire. However, any flue that has suffered from a chimney fire should always be inspected along its length prior to being reused.
The entry point into chimney and flue linings is stainless steel.
Stainless steel can be available in either a flexible format (to accommodate bends in the chimney or flue) or as a rigid piece. Flexible stainless steel liners are supplied as one long piece whereas rigid stainless steel is supplied in sections which are slotted together.
Flexible stainless steel flue liners are available from Turner Baker Ltd for either multi fuel stoves or for gas and oil appliances.
The Positives and Negatives of Stainless Steel Liners
• Relatively inexpensive
• Can be installed as a freestanding unit either on the inside or outside of a property
• Can be used to refurbish existing flues
• Short lifespan – many stainless steel liners are only guaranteed for 10 years
• Will not withstand any chimney fire
• Can corrode rapidly with the use of certain fuels
• Easy to damage on installation
Pumice Flue Liners from Turner Baker
Isokern Flue Pumice is a natural insulator. This is the unique property that separates pumice from all other chimney materials.
The insulating properties of Pumice allow the flue gases in the chimney to quickly reach their optimum temperature enabling the heating appliance to reach its optimum performance shortly after lighting.
It also keeps the chimney warmer longer as the heat output of the appliance decreases – once again aiding performance and reducing the likelihood of condensation and soot build-up.
DM (Double Module)
The Isokern Double Module block system is a high quality chimney system, used extensively in Scandinavia and other parts of Europe. The double wall system maintains flue gas temperatures while preventing heat transference to the outer casing. The separation of the inner and outer components also allows for thermal movement, reducing the risk of cracking and subsequent leaking or staining. It is simple and quick to build. The Double Module is available in 3 outer casing sizes and is ideally suited to new builds and constructing entirely new flues and chimney stacks.
Pumice Flue Liners
The Isokern flue liner range consists of over 17 different sizes. They can be used for new build, extensions and relining existing chimneys.
Please call Turner Baker Ltd on 01432 839123 if you are interested in any of these lining products and we will be happy to advise you on the system that is right for you.