What’s that white stuff?

The obnoxious droning of the neighbor’s pressure washer has got me thinking about stains (and ear plugs). With masonry the most common stains are white. Perhaps you have looked at your chimney and wondered “What is that white junk and how do I get rid of it?”

The white stuff is called “efflorescence” and is salt residue.  This salt is left behind when water moves through the brick and mortar and evaporates on the surface. This is common on new work because mortar is mixed with water and as it cures it heats up and forces water (and salt) out of the wall. When efflorescence occurs on an older wall it is a sign that water is getting into the masonry somehow.

In the case of efflorescence on fresh brick and mortar, we remove it with an acid wash. Efflorescence on existing structures is removed in the same way, but it is important to find out where water is entering the structure, to keep the white stuff from coming back.  Masonry sealers can also be used on the brick, mortar, and concrete to deeply penetrate the material to prevent salts from reaching the surface.