If you’ve ever noticed a white, powdery deposit on your brickwork and wondered what it is and why it appears, then wonder no more, efflorescence on brick walls is a common issue and the good news is that it is usually a harmless, temporary problem.
Let’s examine what efflorescence on brick walls is, what causes it and what, if anything, can be done about it.
What is efflorescence on brick walls ?
Efflorescence is a powdery deposit of salts and staining on the surface of brickwork which is usually white in colour but can also appear green, yellow or brown.
It arises when construction materials become saturated. Water dissolves the natural salts contained within the bricks and mortar and these salts are then carried out and deposited onto the surface of the brickwork when the salt solution evaporates.
What causes efflorescence?
Efflorescence on brick walls is relatively common and can be caused by construction materials getting wet during the building process. If materials are stored incorrectly and not protected from the elements they can become saturated. Once those materials are incorporated into the structure of a wall the moisture will, over time, make its way to the surface of the brick bringing salt deposits with it.
Alternatively moisture can be introduced to the brickwork as a result of condensation or an ineffective damp-proof course, or by an external factor such as a burst or leaking pipe.
Is it harmful?
Efflorescence itself is not harmful to the brickwork, although it can look unsightly on external walls. It is often a temporary seasonal problem with a build-up of salts appearing in spring following the wet winter months.
However, efflorescence on brick walls indicates that the wall has been wet so it is essential to investigate the cause of the damp. If the issue persists there may well be a problem with the design or construction which is allowing the brickwork to remain damp.
Can efflorescence be removed and treated?
The most effective treatment for efflorescence on brick walls is time. Damp materials will usually dry out and efflorescence will typically decrease or disappear with warmer weather.
If there is a serious build-up of deposits a good scrub with a stiff, dry brush will usually remove the worst, and this can be followed up with a softer dry brush to remove as much salt as possible from the surface of the wall.
If efflorescence on brick walls persists there are treatments available which generally contain a weak acidic solution which neutralises the salts.
However, as the old saying goes “prevention is better than cure” so we recommend covering building materials during the construction process where possible and protecting partially completed structures to prevent saturation of the brickwork.
Attention should also be paid to damp proof courses, sills, copings, flashings and other areas which have the potential to allow the ingress of water over time. If water is allowed to continuously enter the construction material then efflorescence will continue to form.
Stained or damaged brickwork – is it definitely efflorescence?
Efflorescence on brick walls can sometimes be confused with spalling, where the surface of the bricks become damaged and crumble due to freezing and thawing of water-logged bricks during the winter months. However, spalled bricks will not necessarily exhibit staining and the two issues are unrelated.
Another cause of staining on brickwork that could be confused with efflorescence on brick walls is mortar staining. This arises when a lack of care and attention during the construction process results in residual sand and cement being allowed to set on the brick face. Again, this is unrelated to efflorescence and mortar staining can usually be removed with brick acid and a wire brush.
