IAQ and efflorescence. Ever wonder what that white stuff is?

One of the indicators of possible moisture intrusion is a white, powdery or crystalline substance sometimes found on the surface of concrete, plaster and masonry. Known as efflorescence, bloom, or sometimes effervescence, it occurs as water containing soluble salts evaporates from the surface of an object. On exterior surfaces it is usually only an aesthetic concern. When found indoors, however, it indicates ...

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