Is Efflorescence Dangerous?

Efflorescence is a white stain that shows up on concrete surfaces. It looks almost as if the concrete was spray-painted with white paint. Efflorescence shows up on concrete when the moisture in the structure solutes the salts in the concrete. As the water rises to the surface of the soil, it brings along the displaced salt. The water evaporates, but the salts form clumps along the surface of the soil.

Efflorescence is not dangerous, at least not in the way that mold is. It’s just salts and minerals, so exposure to efflorescence will not affect your health. However, the existence of efflorescence on your concrete can indicate that you have moisture problems, especially if the efflorescence is on concrete that is over one year old. If water is somehow saturating the concrete and then escaping to the surface, it indicates that your basement walls are somehow getting saturated with water. Besides being a problem sign, efflorescence can actually accelerate the deterioration of concrete.

When the salt particles accumulate on the surface of the concrete, they actually block moisture from evaporating out of the wall. Water is an erosive element, so if water gets trapped inside, it will displace the concrete’s particles to the point where there will be cracks and tears. All concrete cracks, but those that are exposed to water frequently tend to crack more than dry concrete structures. In a driveway or pool deck, minor cracks are expected, but in a basement wall, it could mean more flooding. The older the concrete is, the more likely it will crack, so be wary of foundations that were built over 15 years ago.