Over time the outside or inside walls of chimney’s are likely to crack due to the freeze-thaw effect causing mortar joints to flake, wash out or crack after out 25 to 30 years of exposure to the elements.
Chimney’s are also subject to intense heating and cooling cycles, condensation and chemical reactions caused by flue gases.
A combination of acid attack, salt crystallisation and erosion can also make a chimney lean.
The risk increases with the age of the building, particularly if you live in a ‘historic’ home.
However a good contractor can perform a range of tasks in order to repair any damage to your chimney and ensure its longevity, including chimney pointing or repointing and lining/relining.
The three basic types of flue lining are cast linings, sectional solid linings and metal linings. Cast linings – these are relatively easy to install and are usually the least expensive. Solid liners – can be made of refractory concrete, pumice concrete or terracotta. They are usually used for particularly large and straight chimney stacks. Metal liners – can be rigid, flexible or gas flex. The first of these are usually used for wood burning stoves. Flexible liners have a double skin and are made from stainless steel. They are available in a wide range of diameters and are usually simple to install. Gas flex liners are single skin and used primarily for gas fires and boilers.
Chimney lining is a professional job that must be carried out by a professional contractor with appropriate certification (e.g. HETAS or NACE). This is because of the particular risks from badly installed flues, especially from carbon monoxide.
Chimneys should also be inspected twice yearly and if necessary swept by a member of the National Association of Chimney Sweeps (NACS). This will protect against the risk of chimney fires and carbon monoxide poisoning.
If the chimney needs to be rebuilt it must be done according to safety codes approved by NACS. It is also worth bearing in mind that chimneys are heavily regulated by building regulations and dangerous chimneys may therefore be considered unsuitable for occupation by building regulations inspectors.
Whether your chimney needs completely rebuilding, relining or repointing, Builder Guide’s professional certified roofing contractors will be only too happy to quote for the work that needs to be done.
Over time the outside or inside walls of chimney’s are likely to crack due to the freeze-thaw effect causing mortar joints to flake, wash out or crack after out 25 to 30 years of exposure to the elements. Chimney’s are … Continue reading