There is a white stain on my concrete.. What is it?

The Meaning of efflorescence on your concrete wall

Stains are evidence of dampness in that area of the wall the acidic residue that you see is also called efflorescence. You will recognize efflorescence as it will be white and may even be fuzzy in appearance or to the touch.

Efflorescence forms when water infiltrates a concrete wall and dissolves minerals. As the water evaporates from the surface of the wall the mineral deposits are left behind. Usually, efflorescence is a visual problem, sometimes the efflorescence crystals grow inside the surface of the wall, and it causes spalling. Spalling is when the surface peels, or flakes off. The salt is pushing from the inside out and may be the cause of crumbling and deterioration.

In this video, you will see a lot of examples of efflorescence appearing. The setting is an underground parkade of a fairly new apartment. The situation is a commercial application but the principle is the same for residential and commercial. You may find in a residential house setting the process could be a little different depending on access and the types of foundation crack repair needed to do the repair.

If you see efflorescence you could have a moisture problem and if gone untreated it can cause deterioration.

If the efflorescence is removed, and then returns, it is a sign that water is entering the wall and forcing the salts out. If the efflorescence does not return, then it was probably caused by initial moisture and salts from when the concrete was placed.

If you are concerned about efflorescence on your concrete walls or if you are experiencing a leaky basement and are in need of wet basement repair of some time call an expert.

Phil Russell of CrackMaster Concrete is easy to talk to and is a Master in dry basements.

Call Phil 604 -614-2615 for all of your concrete foundation needs.