Efflorescence is a deposit of soluble salts, usually white in color, which sometimes appears on the surface of masonry or concrete construction. Often efflorescence is apparent just after the structure is completed, when the builder, architect and owner are most concerned with the appearance of the new structure.
There is no need to panic; however this phenomenon has a simple explanation and an equally simple solution. A combination of circumstances causes efflorescence:
1. First, there must be soluble salts in the masonry.
2. Second, moisture must be present to pick up the soluble salts and transfer them to the surface.
3. Third, some force, evaporation or hydrostatic pressure must cause the solution to move.