What does efflorescence mean to the home inspector?

Efflorescence is the salt deposits on a masonry or concrete surfaces that is associated with water moving through walls. Water in the walls dissolves salts from the mortar and concrete or masonry.  As water evaporates off of the wall surface, the salts are left behind as crystals on the masonry.  They are usually whitish, but they can also be green or brownish as well.  They are soft, powdery, and usually project 1/4″ or so out from the wall if protected from rain.  It would be more of a stain if not protected.

The efflorescence itself is often not an issue, but it does suggest that water is in the concrete or masonry.  In our winters spalling is an issue when water freezes.  The goal is to try to stop the water from getting into the masonry.

The crystal deposits on the fee of the masonry are largely sulfates or carbonates of sodium, calcium, magnesium, aluminum, and potassium. Portland cement mortars may be the source of the sodium and potassium. Other soluble salts such as chlorides may also be deposited as water evaporates from the surface of the masonry.  There may be a lot of efflorescence immediately after construction, diminishing and disappearing over. the first few years.  Seasonal efflorescence is also common. being noticeable only during colder weather.

Control Wetting To Control Efflorescence.

Bricks that absorb or trap water easily are more prone to efflorescence than bricks with a low absorption rate.  Efflorescence can sometimes be reduced by rinsing the wall with water or dilute hydrochloric acid. although the additional water can Mae the problem worse. in some cases.  Preventing chronic or continuous wetting of the masonry should help control efflorescence.

Whenever we see the efflorescence, we look for the water.  (except on new construction)  It is the water that is the problem and we need to keep it away from the concrete or masonry that is affected.