What is the crystal shaped deposit on my basement wall?
I know it is not mold. It most likely is efflorescence, a crystalline or powdery deposit on the surface of masonry materials like concrete, brick or clay tile. Appearing fluffy or fuzzy, it is usually white but may be other colors. It develops when water seeps through the wall or floor. The water dissolves salts inside the object while moving through it, then the water evaporates, leaving the salt on the surface. Efflorescence can be removed because it is salt. Most salts are water soluble and can be removed by high-pressure water jet, light sandblasting or dry brushing. The heavy accumulations or stubborn deposits may require washing the stains with a dilute solution of muriatic acid (1 part acid to 12 parts water) and scrubbing with a stiff bristle brush. Dampen the surface with clean water before applying the solution. After scrubbing thoroughly, flush with clean water to remove all traces of the acid. Then paint with a masonry water proofing paint, not a water sealer. Excavating ar
