Chimneys are often neglected when it comes to home maintenance. Whether you have a working flue or not, it is important to have your chimney inspected regularly. If left unchecked minor problems can become costly and even hazardous.
Some faults, such as leaning stacks or larger cracks, may be visible from the ground. Other problems like damaged pointing, fine cracks, eroded stone, damp and leaks may only be picked up during a roof inspection. Roofs are inaccessible and unsafe places for the average householder, so seek professional help from a roofing company rather than attempt such an inspection yourself. Under Health and Safety law, most chimney repairs require scaffolding to be erected on the roof. If possible, save money by combining chimney repairs with other roofing work.
Stability is one of the most common problem areas. Chimney stacks bear the brunt of the weather, resulting in significant wear and tear to the external brickwork and pointing. If past repairs have been carried out using the wrong type of mortar, this will speed up deterioration. This can occur when porous Victorian brickwork is re-pointed using hard modern cement mortar. Bricks can work loose and the chimney stack may begin to lean. Chimney stacks may also lean when hot flue gases damage the internal brickwork, or when the chimney breast has been removed. Yet another cause of leaning stacks is the drying action of the prevailing wind causing mortar shrinkage on one side of the stack, while the mortar expands on the other, damper side. Leaning stacks need to be monitored and may warrant removal if the lean becomes severe.
Chimney pots become unstable when the flaunching decays, posing a hazard to passers-by. The flaunching is the mortar that holds the pots in place and also protects the top of the stack. Frost can cause cracks in the flaunching. Your roofing contractor can replace the flaunching and secure the pots, or replace them too if they have sustained damage.
Damp penetration is another problem area. Flashing – the metal strips that seal the junction between the roof and stack base – may become defective, allowing rainwater to seep into the stack and down the flue into the house. Always ensure that the height of flashing is sufficient – add more if necessary. Replace any faulty pieces of flashing, and secure any flashing that has worked loose. If the mortar between the brickwork is cracked, this can allow moisture to seep in, too. Damp caused by condensation can be a problem in working flues, made worse when newly-cut wood is burned. A simple solution is to install a flue liner. Cover an unused flue to stop rain and damp from entering but make sure the flue is well-ventilated so that airflow will cause moisture to evaporate.
If you spot a potential problem, contact a roofing company experienced in chimney repairs for further help and advice. Don’t wait until it’s too late – some damage is irreversible and may eventually result in major work like removal or reconstruction.