Chimneys and Lining
The purpose of a chimney is to get rid of all the gases that are produced during combustion. The gases go up into the chimney because hot air rises so if cold air was leaking in or the stove was burning at a very slow rate then this would cool the gases and then they will not exit the stove. Lining systems can be placed in the chimney to replace the flue. The lining system can be made with the appropriate dimensions in mind. Insulation can be added to reduce the risk of draught and improve the efficiency.
Chimney Technology
Flue: the flue is the pathway that removes the gases from combustion from the stove to outside of the building.
Chimney: the structure that surrounds the flue system.
Flue Liner: the flue liner is thing that creates the flue within the chimney.
Chimney Terminal: this is the thing that is at the top of the chimney.
Flue Pipe: the pipe that connects the stove to the flue liner.
Why Line Chimneys?
There are many reasons why a chimney might need to be lined, most of them because of safety reasons. New chimneys may need to be relined but chimneys that are older than 1965 will need to have a modern lining put in because:
The flue may not be up to standard and may start to let gases into other rooms.
Condensates or tar can get in through the chimney and cause staining.
It can improve the efficiency of the stove when insulated.
Flue systems that are faulty may result in poor updraught as the gases won't be able to flow through.
Larger flues can affect the stoves performance so many manufacturers recommend using smaller flues.
Methods of Chimney Relining and Renovation
There are many different ways that a chimney can be relined. These are:
Using clay, pumice or refractory liner that is installed by cutting into the chimney or lowering it from the top.
Insulating concrete that is pumped in and around the chimney.
Steel liner that is lowered down from the top of the chimney.
Spray on coating
Ceramic coating
The way you reline your chimney depends on your individual situation so it is recommended that you seek professional advice to see which one suits the needs of the chimney.
Building Regulations
There are no regulations that a chimney that is already in place needs to lined but when installing any appliance the installer needs to make sure that it is free from faults and suitable for the use. If any work is done on the chimney when installing an appliance then it needs to be done by a competent person or approved by the local building control. If you are changing fuel type, e.g. from solid fuel to gas, then this is subject to regulations.