What is Efflorescence?
Efflorescence is the formation of salt deposits, usually white, on or near the surface of concrete and clay bricks, causing a change in its appearance. Apart from the discolouration efflorescence is harmless. This is best described as being ‘a temporary skin problem and not a deep-seated disease’.
Efflorescence on Bosun Pavers
In Gauteng, efflorescence is most obvious in the rainy summer months, but may be observed throughout the year, especially in irrigated areas and after a sudden drop or rise in temperature. It can occur from within the concrete or from the subgrade (soil below the pavers). With time, efflorescence becomes less extensive and in most instances it disappears completely. Light coloured pavers might show the deposit less than darker coloured pavers.
Efflorescence is a natural phenomenon that occurs through one or a combination of the following processes:
Chemical processes
Formation of efflorescence can be the result of a reaction of concrete constituents with carbon dioxide and/or sulphurous gases.
Physical processes
The formation of efflorescence could be caused by a number of physical processes involving both salt and water transfer in and out of the concrete product, the aggregates used in installation and the subgrade or earth beneath the pavers
How to remove efflorescence
Efflorescence is difficult, but not impossible to remove. In many instances rain will simply wash efflorescence away. We believe the best cure for efflorescence is to just leave it as it will go away with time.
However, should you want to remove efflorescence promptly, or have a severe case, we recommend using a specialised remover, such as Guard Remover Eco Efflorescence & Cement. Specially formulated to remove efflorescence, this product is less aggressive than other solutions. It is non-corrosive, eco-friendly and safe to use. We recommend contacting Cretesol for more information on this product.
Other solutions and “home remedies” for the removal of efflorescence include:
- Dry brushing and the avoidance of water to clean effected pavers.
- Washing with clean water or a mild detergent.
- Using a 50/50 mix of white vinegar and water. Using a scrub brush over the affected areas.
Irrespective of the method used to clean efflorescence, it could reappear (in some instances more severely than before).
Bosun cannot guarantee efflorescence-free products – prior-to or post-installation. Our comprehensive Five-Year Guarantee does therefore not cover efflorescence.
How to prevent efflorescence
In recent times, the applications of penetrative paving sealants or protectors have been proven to be successful in preventing efflorescence from returning. Penetrative sealants and protectors saturate and fill the surface capillaries (pores) of the paver, in turn they limit the transference of efflorescence to the surface of the paver by trapping it inside.
For a cost-effective solution, we recommend using a penetrative paving protector such as ImperGuard. Supplied by our sister company, Cretesol, ImperGuard is a penetrative paving protector designed to provide essential protection against the negative effects caused by damp, water ingress, acid rain erosion and to limit the appearance of efflorescence.
We highly recommend seeking professional advice when removing efflorescence and when sealing or protecting paving. For more information on the removal and prevention of efflorescence, visit www.cretesol.co.za
Severe white efflorescence
The same site six months later
Severe white efflorescence
The same site six months later