Have you noticed stains or damage to your brickwork and wondered what causes it. This article looks to delve a little deeper into the most common causes of damaged brickwork.
Efflorescence salt staining
Efflorescence is a white staining on brickwork caused from natural salts. The reaction occurs when water mixes with the salts that exist in the construction material. The water breaks down these salts and once evaporated, it leaves a white deposit.
How can I prevent efflorescence?
It is difficult to prevent efflorescence as the materials may have been soaked during the construction process. The best way to resolve the issue is to let the wall completely dry out before treating the surface with a salt neutralising solution.
How can I treat this on external walls?
The natural weathering works as a continual remover for brick staining. However, if the build-up of of efflorescence is particularly bad, then it could be recommended to scrub the affected area with a stiff dry brush and dust off any excess salt.
If you fail to remove all the salts from the surface of the wall, the crystals can re-dissolve back into the brick and cause the same issue again. There are also acid brick stain treatments but you need to be careful when adding moisture to the wall without removing the initial problem.
How can I treat this on internal walls?
The appearance of efflorescence is different on internal walls. When this appears on plaster it leaves a white fluffy residue that can blister wallpaper and paint. The salt crystals can cause the plaster to crack. This problem can happen in a building of any age or structure, it is all dependant on if water is passing through the materials. Water will always find its way out of a wall and leave salts behind.
What Is Spalling?
A common mistake is the confusion between efflorescence and spalling. However the two are very different. Spalling is a specific type of weathering which occurs in porous building materials, such as brick, natural stone, tiles and concrete. Dissolved salt is carried through the material in water and crystallizes inside the material near the surface as the water evaporates.
How can I treat spalling?
The best way to resolve spalling is to remove the bricks completely and replace them one by one. This should be done carefully by drilling small holes around the brick to isolate it and protect the other bricks.