What is efflorescence?
Efflorescence is the process by which salt migrates to the surface of a porous material where it forms a coating. Found on walls and other brick, stone or concrete surfaces, it occurs when evaporating water leaves behind salt deposits on the masonry and appears as a white powdery substance. There are many installation problems which may lead to efflorescence:
- Using masonry products that are not fit for purpose or of poor quality
- Improper ground storage of façade material
- Use of masonry without sufficient ventilation
- Use of masonry in areas that lack a proper moisture barrier
- Joint material failure
how to prevent or remove efflorescence
Prevention is always better than cure! Good site practice will reduce the amount of efflorescence. Be sure to keep stored bricks under cover and ideally off the ground. It is also important to protect newly laid brickwork from the elements.
Efflorescence is temporary. In most cases it will disappear in a few wet winter months in this country, therefore the best solution is often to let it wash out naturally.
Simple washing can sometimes remove efflorescence. Scrub the affected area with a wet sponge or brush and plain water. Always be sure to rinse thoroughly, if you leave dissolved salts on the surface, they’ll return as new efflorescence. Clay naturally has a high salt content, therefore removing efflorescence in this way is often only a temporary solution – wet weather can bring salt back to the surface again.