Efflorescence

Efflorescence is the white powdery substance commonly found on masonry surfaces.  This white powder is actually deposit of water-soluble salts left on the surface of masonry as the water evaporates.

Efflorescence occurs when three conditions are present.

1, Water-soluble salts are present in the masonry.

2, Sufficient moisture to turn the salts into a soluble solution.

3, A path for the salt solution to travel to the masonry surface where the water can evaporate and leave the salt behind.

Removing Efflorescence

A dry brush can usually be used to remove the salt. A mild detergent and a stiff bristle brush can be used for more difficult areas.

For even more difficult areas, sandblasting is often used to remove the discoloration.  Sandblasting will damage the surface of the bricks and mortar joints so it should be used with caution.

Chemical cleaners (such as a muriatic acid solution) are now available as an alternative to sandblasting.  When using a chemical cleaner it is easier on your masonry to use several mild applications rather than a single strong one.