Chimney troubles: Tackling soot stains and structural risks
Soot from the chimney can leave dark, unpleasant-smelling stains on building walls. These stains ruin aesthetics and signal more serious construction problems. Although they often appear in older buildings, they can also affect new houses. What causes them to occur, and how can they be removed?
These stains represent a problem that cannot be ignored, as they result from the condensation process in the chimney. Water combined with soot slowly penetrates the walls, becoming visible inside the building.
How and why does efflorescence occur?
The appearance of this efflorescence typically indicates advanced issues with the chimney pipe. It's important to identify and remove the source of the problems, usually narrowed down to two possibilities.
The first is the exhaust gases being too low in temperature. This often occurs in tall chimneys or with modern furnaces with low heat emission, including pellet stoves. Under these conditions, condensation and moisture can accumulate on the chimney walls.
The second cause could be a leaky chimney, allowing rainwater to enter. The combination of water and soot promotes the formation of unsightly stains.
How to prevent efflorescence?
To prevent this efflorescence, consider insulating the upper parts of the chimney, for example, using mineral wool. This will help retain the smoke's heat in the chimney for longer.
However, if stains have already appeared and the chimney has not been properly insulated, more radical measures are necessary.
Installing a chimney liner, made of ceramic or acid-resistant sheet metal, effectively isolates the chimney's masonry construction from water, eliminating the problem long-term.
Ensuring comfort and safety, temporary masking of stains with paint is not sufficient. Efflorescence results from the penetration of water with soot through plaster and joints.
Therefore, the best solution is removing damaged plaster, repairing joints, and proper impregnation before re-plastering. This action not only restores aesthetics but also ensures the safety of residents by protecting against harmful gases.
