Masonry: Efflorescence

So efflorescence may be visible in concrete, in CMU, in masonry, in brick, in stone, in mortar. It's this white stuff that appears on brick, for example, and that can be washed or brushed with a steel wire brush. But it's unsightly, and it happens when there's water-soluble salts, maybe sulfates, maybe chlorides, something like that present in the CMU, the mortar, maybe the grout, or even the soil behind a wall, for example. So moisture from rain or, I don't know, construction water or groundwater or something like that will dissolve the salts and then as the water migrates to the surface and then evaporates it leaves behind these salts. So efflorescence is that white stuff. Продолжение следует...