Chimneys can be very problematic, but by having them regularly checked and repaired you can extend their useful lifespan and reduce the chance of damp penetration occurring internally.
Chimney defects are often difficult to identify and repairs are frequently postponed by home-owners due to the location of the chimney – being on the roof. Out of sight is often out of mind!.
There are a number of ways rainwater can penetrate through a chimney, especially if it’s been poorly maintained. Some common faults include cracked chimney pots, defective render or brickwork/jointing, porous bricks or stone, a damaged, misplaced or missing damp proof course (horizontal damp barrier) and failings in the flashings (the watertight detail between the chimney and roof).
High concentrations of hygroscopic (moisture attracting) salts can also build up through burning fossil fuels such as coal and wood. These salts can easily migrate into plaster on the chimney breast where they can cause damp patches by attracting moisture from the air. Although not always serious, the defective plaster will need to be replaced if the stain is to be removed.
It should be remembered that chimney flues can often be defective unless they are relined. We recommend that flues are always tested prior to any use and swept annually.
While carrying out a survey, our Surveyors will always closely examine chimneys using binoculars where possible, looking for any of the tell-tale signs that external defects may be allowing water to enter the main building structure. Internally, we will alert clients to any visible damp patches and active staining to timbers which can also lead to decay if the correct repairs are not put in place.