What Is Efflorescence And Why Is It Confused With Mold?

Efflorescence is a crystalline deposit of salts that are generally white and chalky and can be seen on surfaces such as stone, stucco, brick, and concrete. It’s a pretty common substance that is often confused with mold, but mold is usually green, blue, or black (though it can indeed be white). Efflorescence occurs when salts are deposited on the surface of walls, floors, or ceilings due to water that finds its way through brick and concrete and then evaporates, leaving salt behind. It’s commonly found in newly constructed structures or in buildings with water leaks. Varied surfaces and different areas of the country can produce different efflorescence colors, but again, it’s often white with a grayish tinge.

If you’re further wondering how efflorescence varies from mold, remember that mold grows and efflorescence doesn’t; mold thrives on numerous surfaces whereas efflorescence doesn’t spread; and mold is a fungus and efflorescence is the result of moisture evaporating into salt deposits. Efflorescence is associated with moisture that can come from leakages, sprinklers that may be soaking the exterior of a home, airborne moisture that occurs in the winter, and groundwater that gets into a house’s foundation.

For efflorescence to occur, salt also has to be in the picture. Salt comes from a variety of sources and may even be present inside the brick, stone, or concrete portions of a home. In some cases, the source may be the grout or Portland cement that holds surfaces together. Salt can also come from the soil and be present in the water itself in areas that have hard water.

Does Efflorescence Cause Mold Growth?

Efflorescence does not cause mold growth, but there is a caveat. In general, if notice efflorescence in your home, you should check for mold growth. That’s because, as many people know, mold thrives on moisture. So if you see efflorescence in your house, which is caused by moisture, you may have mold. Wet basements are especially prone to efflorescence growth.

Where Can I Find Efflorescence Occuring In My Home?

This substance can be found on walls, floors, retaining walls, basements, and surfaces that are made of brick, stone, concrete, and stucco. If a floor or another concrete surface has been sealed, you might observe a white blush under the sealer. This is a cause for concern for homeowners with sealed concrete floors or other solid surfaces in which efflorescence is present.
As a precautionary note, efflorescence is known as a common defect found by home inspectors during a real estate home inspection, so keep that in mind if you’re looking to sell your house.

What Do I Do If I See Efflorescence On Concrete Or Brick Or Other Surfaces?

If you see this white powdery substance in your home, try to find out where the leak may be coming from. Water leakage means mold likely isn’t far behind, so it’s important to remove it and restore the area with the help of a professional. Efflorescence can be removed on some surfaces using a dry brush. Other salts can be washed away with a hand brush, mild detergent, and a water rinse. Power washing is another method that can be used, depending on the surface. As you can see, removing efflorescence depends on the type of surface you’re dealing with.

You may want to consult with a contractor to see if there is a chemical cleaning agent that is recommended for your surface and get instructions on how to use it safely. For example, a weak solution of muriatic acid is used for some surfaces, but it might damage others.

In general, cleaning efflorescence from a surface is an ongoing solution rather than a cure. Sealing a surface might be a solution, but if water still finds its way into the surface, you could end up with spalling, which is a destructive process that should be avoided.