warning that the flue could be damaged or defective. Defective flues can be repaired by inserting a pre-formed flue liner into the flue, although this can be a relatively expensive operation in a multi-storey house.
As open fires fell out of favour it became common to remove the original open fireplaces and brick up the openings. Although this seems a relatively straightforward cosmetic operation, it does pose a number of potential problems. The original open fireplaces provided an efficient form of ventilation. Even if the fire was not in use the flue would promote air movement with warm air tending to rise up the flue and escape through the chimney. This helped to reduce condensation in houses. It should also be remembered that the flue is open at the top. When coal fires were being used this was not a problem as the heat from flue gases would keep the chimneys dry. If the fireplaces are sealed up rainwater can still enter the top of the flue, but there is no longer sufficient air movement through the chimney and flue and dampness within the chimneys can be a problem.
When fireplaces are sealed up internally it is important to make sure that a suitable terminal is fitted to the top of the chimney pots. This should prevent rain entering the flue whilst still allowing ventilation. It is also necessary to provide ventilation to the flues within the building so that air can still enter the bottom of the flue and escape through the terminal on the chimney stack. When carrying out Homebuyer Reports or Building Surveys the surveyor will check that any redundant flues are fitted with suitable terminals at roof level and also make sure that the flues are ventilated inside the house.
As we said earlier, brick chimney breasts are quite bulky and can occupy a relatively large area in smaller houses. Not surprisingly, quite a few chimney breasts were removed when the open fires were no longer required in order to free up much needed floor space. This is not a problem, provided that the work is done properly!
It is quite unusual for the chimney stacks to be removed above roof level, as these are often shared with a neighbouring property and the cost of erecting scaffolding and making good to the roof tiles or slates would be prohibitive in many cases. It is more usual for the chimney breasts to be removed inside the building and for the chimney stack to be left in place. It is important that the remaining chimney stack is adequately supported. This can be achieved in a number of ways. The traditional method was to support the remaining chimney stack in the roof space with steel ‘gallows’ brackets. This is a triangular bracket made up of steel and bolted to the wall beneath the chimney stack. The security of these brackets is largely dependent on the quality of the brickwork underneath the stack; if the brickwork is very soft or loose it may not be possible to obtain a secure fixing for the bolts.
A more secure alternative, and one that many local authorities now insist on, is a steel ‘I’ section beam that sits on the load bearing walls of the house and supports the stack above. It’s worth mentioning at this point that removing a chimney breast is considered a structural alteration and it is necessary to get approval from the Local Authority Building Control Department. If the chimney breast is on a party wall it will also usually be necessary to a serve a Party Wall Notice on your neighbours.
Surveyors will always check whether or not chimney breasts have been removed when carrying out Homebuyer Reports and Building Surveys. If the chimney breasts have been removed on all floors it is usually possible for the surveyor to see from within the roof space how the chimney stack has been supported, or not, as the case may be! Over the years we have seen quite a few different methods of support, ranging from text book gallows brackets and steel beams at one end of the range to odd pieces of timber and even no support at all at the other extreme. We even know of a surveyor who, after struggling to lift an extremely heavy loft hatch, found t