Chimney and Flue Lining - WHY?

A chimney is a passage from the place of combustion to the outside world. Warm flue gases should rise through this passage to the point of exit. For a chimney to operate satisfactorily it should be smooth, warm and as straight as possible. If a chimney is irregular and rough, or cold and damp, flue gases will move slowly. Cooler gases will mean inadequate chimney suction and poor flue gas speed.

We always advocate flue lining where possible the following are some of the reasons:

• Efficiency: A flue liner will substantially decrease your chimney volume. Consequently, higher temperatures will be maintained and flue gases will travel faster, generating a greater and more consistent draft. When required, flue liners can be insulated, increasing flue temperature.
• Chimney Fires: The combination of a clean burning stove and a warm flue liner should mean chimney fires are a thing of the past. Chimney fires are a common and frightening occurrence in an unlined chimney and may cause substantial damage.
• Leaking Flues: A well installed stove should emit no smoke or fumes to the room. If a flue is damp and cold it will produce a poor draft, this poor draft may reduce further during slow burn periods as the flue cools. Chimneys are usually in much better condition externally than internally. Many years of sulphur attack may have eaten half way through brickwork and mortar. Internal feathers dividing one flue from another may have perforated or collapsed allowing flue gas to pass into redundant, uncleaned flues.
• Sweeping: It is far more effective and convenient to sweep through a stove and up a liner than to sweep through a trap door in a register plate or flue pipe – in fact many sweeps will only sweep a lined chimney. A warm flue will collect less deposit, cleaning will be much easier and condensation should not occur in the flue. It is possible to clean a lined flue well, leaving the liner almost as clean as new. It is rarely possible to remove all deposits that accumulate in unlined flues as there are always holes and corners a brush does not reach.