Even if the brickwork on your house is in good condition you should inspect your chimney stack for signs of wear. The mortar pointing in-between the brickwork on your chimney stack can begin to crumble and crack over time because of the constant weather exposure. Rain, wind, snow, frost and even the sun all play a part in the health of your chimney! Worn mortar joints open areas between the bricks and allow moisture to get into the chimney, this leads to the possibility of chimney collapse and expensive chimney repairs. Repointing a chimney is a common repair for the homeowner and isn’t usually that expensive depending on the condition of the chimney stack.
Repointing chimneys involves putting up scaffold be erected to allow the builder to work safely. The condition of the brickwork can be inspected more closely from the roof and a proper assessment can be made. Often signs of cracking or leaning can’t be seen from the ground, but if you suspect there may be a problem with your chimney or it is in need of repairs you should have a reliable roofer make an inspection.
Chimneys need to be kept in good condition as they can become very unsafe if not properly maintained. Even small ones are built with a lot of bricks and if they were to collapse it is best not to think about the damage they can cause. As well as the bricks chimneys will also have chimney pots on top of them, some have as many as 6 or more and these add up to a large amount of weight.
When repointing chimneys an inspection of the top of the chimney called “flaunching” should be made and if there are any cracks visible or if it has eroded away then this should be replaced with a waterproof concrete. The flaunching not only helps the water to run off the top of the chimney but also helps to hold the chimney pots in place. Often if there is no flaunching left the only thing that holds the chimney pots in place are the weight of the pot itself!!
Older chimneys were often built with weak mortar which over time literally turns to sand and it is possible to take down chimney stacks by hand with no tools. If your chimney is in this condition it would not be wise to simply repoint it but to have it taken down and rebuilt.
If the chimney stack is to be taken down and rebuilt it is difficult to say how much of it will have to be removed. Sometimes it is just the top 3 or 4 courses, called the chimney crown. Usually it is safer to take it down to the flashings providing they are in good condition. If the bricks are in really bad condition sometimes they are removed and rebuilt with new bricks. They should be replaced with engineering bricks or something similar that can withstand extreme weather conditions here in the UK!