If you are having a wood burning stove or similar appliance fitted in your home then you might have been advised to have your chimney relined. If you are uncertain what this means, or what it involves, then this brief guide will explain.
A chimney is the entire structure that takes smoke and gasses from your hearth or stove and up to the atmosphere. The flue is the channel inside the chimney that everything passes through. To work as efficiently as possible, chimneys require enough updraft to properly draw smoke, soot and gas up the flue. This is made possible by the chimney lining, which creates a smaller flue or channel that keeps gas and smoke hotter (and thus rising). The improved up draught means a more efficient chimney. The lining also ensures that the flue provides a smooth and direct passage for the smoke and gas to pass through.
Flue lining deteriorates over time, either breaking down through exposure to chemicals in the smoke or else getting damaged by wildlife, weather and wear and tear. This is particularly true of flues that have been lined with clay tiles – common in a lot of older houses.
A more common reason for chimney lining these days is the wood burning stove. These appliances run to a high level of efficiency, making them cheaper and more economical than open fires. However, this also means that they need to be connected to a very efficient flue – one that is smaller in diameter than for an open fire.
It’s a legal requirement that flues have a 65% minimum efficiency rating before an appliance can be fitted. Anything less and the smoke and gas will cool down in the flue and leave tar deposits on the lining. This not only causes the lining to deteriorate but also risks a chimney fire if the deposits ignite from a spark.
A chimney lining company will be able to take you through the most suitable and cost effective solution for flue relining to meet the requirements of a new stove or appliance. As a general rule steel liners are long lasting and will come with a guarantee. Clay tiles are still used, and a spray on ceramic layer is another option.