Efflorescence is a white crystalline or powdery deposit on the surface of masonry materials like concrete, brick, clay tile, etc. It is caused by water seeping through the wall/floor/object. The water dissolves salts inside the object while moving through it, then evaporates, leaving the salt on the surface.

It can be relatively easy to remove. Oten these salts are water-soluble and, if outside, may disappear of their own accord with normal weathering. This is particularly true of "new-building bloom." The water soluble salts can be removed by dry-brushing or with water and a stiff brush. Heavy accumulation or stubborn deposits of white efflorescence salts can usually be removed with a solution of muriatic acid and scrubbing (1 part acid to 12 parts water -- this is a real acid, follow precautions on the label). Wet the surface well before and after the solution is applied.

Less common salts, that change their chemical structure during efflorescence formation, require proprietary compounds to remove.

Read more about removing and about preventing efflorescence. These links are included for informational purposes, and not to promote this company's products. They were found with a random web search. You can find products locally that do the same sort of things.

 - This information is provided courtesy of FactsFacts.com -