It is important to check the condition of an old chimney, especially when re-opening one, after many years of not being used. A chimney should contain a sealed flue from the appliance to the chimney pot to transport the products of combustion safely to the atmosphere. Over time the condition of the flue can deteriorate. It was only from 1965 that Building Regulations required all new chimneys to be built with suitable flue liners of the correct flue size to protect the chimney.

The check should be carried out by a chimney specialist and would entail the following procedures:

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• The chimney should be swept to ensure that it is clear obstructions such as dislodged masonry or bird's nests

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• A smoke test should then be carried out to establish whether there is any major fault that can cause products of combustion to leak through the chimney walls. A smoke test procedure is given later on in this guide.

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• The structural stability should also be checked, as well as making sure the chimney is wind and water tight.