Flexible chimney liners are made to replace the liner of an exsisting chimney in propertys built after 1965 or to introduce a liner to chimneys built before this date. They are made to connect with an MA (Main apliance) adapter to the stoves flue pipe above the register (or closure) plate and create, in effect, a chimney inside the chimney.
Flexible liners are often known as twin skin or twin wall, this does not mean the liner is insulated but that it is constructed from two layers of steel, a tough outer layer for protection and a smooth inner layer so smoke can travel safely away from the appliance.
Most flexible liner manufacturers recommend installing a flexible liner with insulation such as vermiculite or rockwool tubing to improve efficiency and draught particularly on an external wall.
Chimneys require lining for a number of reasons, The chimney may be leaking smoke into rooms or an adjoining property. Tar can seep through the walls and cause staining inside or outside the building. Eroded systems can become rough, this causes friction, negative updraught and poor performance.
Large flues over 200mm can can effect appliance performances. It is important to check the stove manufacturers instructions as they may specify smaller flues for efficient operation.
There are varying grades of stainless steel flues which are suitable for burning certain types of fuel. 316 grade is suitable for most solid fuel installations, however if you intend to burn mostly smokless fuels which may contain a type of plastic then a 904 grade is recommended.
Chimneys with existing flues can be relined in several different ways. Such as pumice, Using rigid sections of clay, or refractory liner installed by cutting into the chimney wall or by lowering sections down from the top of the stack and infilling with an insulating material. Another way is using Insulating concrete, pumped in and around a baloon, Spray on coating or Ceramic coating by a specialist contractor.
The most cost effective and easy to install is a stainless steel flexible liner in one continuous length lowered down the chimney.
Before lining A chimney you should have it swept thoroughly. The suitability of any of these methods of lining is dependent on each individual system. You should seek professional advice on what is the most appropriate solution for your needs.
North Wales Stoves offer HETAS certified chimney lining throughout North Wales. Visit our showroom or contact us for more information.