What causes efflorescence in a basement?

September 06, 2011

What causes efflorescence in a basement?

What causes efflorescence in a basement? Many of us have come across this strange phenomenon; a white powdery substance comes out of the concrete foundation. It can be on the walls or on the floor. On the floor it can look like it is growing up out of the floor, appearing as a small fluffy stalagmite one might expect to find in a cave rather than in their basement.

This whitish, powdery deposit is formed as mineral-rich water rises to the surface of the concrete through capillary action and then evaporates. Efflorescence usually consists of gypsum, salt, or calcite.

Efflorescence is defined as: “the changing of certain crystalline compounds to a whitish powder or powdery crust through loss of their water of crystallization”. Two conditions must be present to create efflorescence:

  1. A source of water soluble salts.
  2. Water moving through the concrete to carry the minerals to the surface. The water evaporates and leaves the white powder behind.

This white powder is a residue left from water. It indicates that water has evaporated from the concrete. Efflorescence is proof that water was in the basement.

When a house is being sold the home inspector for the buyer will indicate efflorescence is present and that the basement has had water. The resale value of your home could be adversely affected. Buyers expect a dry basement with a strong foundation and no cracks. The market can sometimes penalize you, the seller, up to 10% of the resale price of your home. Actually, any signs that there was once water in your basement such as efflorescence, musty odors and mildew will cause great concern to a potential buyer of your home. When real estate markets are tight, this damage will turn buyers off and cause them to either look elsewhere or seek a significant drop in your price.


People sometimes become worried that efflorescence is a mold growth. It is not organic in nature like a mold or fungus, but is rather a mineral instead. However, since efflorescence is indicative of the past presence of moisture, the potential for mold growth is increased. You can’t have mold without moisture and we now know that moisture was present. By removing the moisture the likelihood of mold growth decreases. You can use dehumidifiers in the immediate area of the moisture and a fan blowing directly on the wall or floor to help dry it out. A whole house ventilation system such as the E-Z Breathe Ventilation System will help keep the humidity in the basement under control year round.

Is a wet basement a sign of a poorly built home? Not necessarily. Homes with both hollow block foundations and poured concrete foundations that are over 25 years old are prone to moisture issues.

The occasional dampness in a home is sometimes a minor problem that you, the homeowner, can solve yourself. However, foundation leakage can be very serious. Of course, the key is to know the difference.

Knowledge is power. If there is efflorescence in your basement you should seek out the advice of a basement waterproofing contractor.

Posted by efflorescence, Ventilation Solutions, white powdery stuff, concrete foundation, Wet Basement, Basement Water, E-z breathe ventilation, E-Z Breathe, leaky basement, Foundation Solutions, basement waterproofing, e-z breathe ventilation system

Doug Lynch

Written by Doug Lynch

Doug Lynch, of Westfield, NJ is a Certified Waterproofing Specialist, Certified Mold Inspector, Certified Mold Remediation Expert, EPA Indoor AirPlus Ally, EPA Lead Safe Certified as well as member of Indoor Air Quality Association, Basement Health Association, North Central Jersey Association of Realtors, Coldwell Banker Concierge Services.

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