Basically efflorescence is a white powdery deposit or residue that forms when moisture from within the masonry product dries out or evaporates leaving behind a white salty deposit.
Efflorescence means that there is:
- Presence of soluble salts
- Excessive amounts of water entering the masonry
Soluble salts can be introduced to your masonry product in a number of different ways. They can be found externally in the fill, soil or sand surrounding the product or brought in by the environment such as sea spray. Occasionally the soluble salts can be found in mortar, grout, dried sweeping sand and even the masonry units themselves.
It is always recommended that a good quality washed bedding sand be used under your pavers to help minimise the presence of soluble salts. As the name suggest washed sand has been washed to remove a lot of the finer material which also removes any of the salts that may be present.
Although efflorescence looks unsightly and aesthetically displeasing it does not affect the product if dealt with quickly and correctly.
Efflorescence will generally disappear over time the process can be accelerated by dry brushing off any residue and removing it from the site by either a dustpan or vacuum cleaner before scrubbing with a brush and clean water. If the salts are not removed from the site they will just be reabsorbed into the masonry product when washed down. Repeat the process until the problem has stopped.