Efflorescence – Basement Vocabulary – White, Chalky Lines of Efflorescence in the Basement

Feb 24, 2014

effloresence1Effloresence in Basements

Have you ever noticed white lines running along your foundation or basement walls? These lines look like chalk lines and if you look closely, they may be raised and bumpy. Efflorence can also present itself as powdery and crystal like build-up.  What is effloresence and why is effloresence in my basement?

The most important thing to know about Effloresence is that is it harmless to humans.

Effloresence will not make you sick nor will it contaminate your home such as mold will do. In fact, effloresence in your basement (or on your outside foundation walls) is so harmless that you could eat it; we don’t recommend this however.

The dictionary definition of effloresence, as a noun and a verb, is:

  • to burst forth : bloom
  • the process of efflorescing; also : the powder or crust so formed
  • to change to a powder from loss of water of crystallization
  • to form or become covered with a powdery crust
  • the process or product of efflorescing chemically

Chemically speaking, effloresence is “the spontaneous loss of water by a hydrated salt, which occurs when the aqueous vapor pressure of the hydrate is greater than the partial pressure of the water vapour in the air. ”

Why is Effloresence in my basement?

Effloresence occurs on basement walls and floors as well as on foundations whenever there is moisture present. Effloresence can occur in any material that is porous. Basement floors and walls are typically made of concrete or brick and these materials are porous. When mosture evaporates in the basement, the walls and/or floors can begin to accumulate effloresence.
Effloresence indicates water moisture in the basement

As water or moisture travels along the concrete or brick walls and floors of the basement, air dries it and leaves behind the salts from the building materials. If you have noticed that your basement walls and/or floors are showing signs of effloresence, then you have, or have had, moisture in the basement. The buildup of effloresence is an indicator of how much moisture is in your basement.


Effloresence build up in the basement could be harmless or it could mean that you have water or moisture conditions that should be addressed. Moisture in the basement can cause poor air quality throughout the home and also cause mold growth.

If you are concerned about the white, chalky lines of effloresence in your basement, call or click below to schedule your basement evaluation. Our basement specialists are available when you need them to be.