Anyone in the masonry or concrete industries has experienced it. The white powder that drives homeowners batty after they spent a pretty penny to have beautiful pavers installed on their driveway or pool deck. What is it?
It won't come off with water. It's efflorescence‚ a major annoyance for both the installer and the homeowner! According to an article from The Masonry Institute entitled "Efflorescence: Cause and Control[1], the definition is:
ef-flo-res-cence (ef, le res‚ ens), 1. a change on the surface to a powdery substance upon exposure to air, as a crystalline substance through loss of water. 2. to become incrusted or covered with crystals of salt or the like through evaporation or chemical change.
The good news is that there are products available to get rid of pesky efflorescence now. Although muriatic acid and sandblasting are sometimes used to remove efflorescence, they are extreme measures.
Depending on the severity of the efflorescence, multiple iterations of the cleaner you select may be necessary. Note, there are cases where the efflorescence is deeply embedded in the surface and will be unaffected by chemical treatments. Once you remove the efflorescence, it still may come back due to the moisture and salts in the paver.
Pro tip: If you have darker pavers, you should consider using an efflorescence remover before sealing, even if there is no efflorescence present.