Efflorescence is a crystal deposit on masonry, stucco, and concrete materials. It's often white in color, and it sometimes looks like "whiskers" on the wall. This is a common problem seen in many basements all over the country. It can be seen inside or outside of the home. The fuzzy, white substance is not harmful to humans and it isn't going to cause adverse health problems as is the case with mold growth.
When this substance is seen in a home, it typically means that there is an underlying moisture problem. If left untreated for too long, the moisture may start to make itself known in other ways. It could start causing wooden materials under the home to deteriorate, or it may start leaving stains on walls or floors. This moisture could also spark the growth of nasty mold and mildew.
What Causes Efflorescence?
When water infiltrates a block or concrete foundation wall, it dissolves minerals. As the water evaporates from the surface of the walls, it leaves behind a mineral deposit. This mineral deposit is seen in the form of white crystals, and this is what you see on the basement walls. While this may seem like only an eyesore, the moisture involved with the infiltration can actually cause spalling of the concrete materials. This can cause the surface of the wall to flake, pop out, or start to flake away and become very brittle.
When the deposits are removed from the wall with a cleaning solution, the problem can still come back. If it does, this is a good indication that there is a moisture problem in or around the home. Often times, homeowners can hire someone to sandblast the walls to remove the stains. However, as said above, it can still come back.
Efflorescence can only occur when the following three things are present:
- Water-soluble salts are in the wall.
- There is enough moisture in the wall to turn the salts into a soluble solution.
- There is a path through the wall for the salts to move through.
To prevent the problem, a homeowner must make sure that moisture is not present. Seeing the crystals on the wall will typically mean that there is a leak somewhere that is letting water inside the home. Once the leak is stopped, the efflorescence can be effectively treated and removed from the wall's surface.
Interior waterproofing systems can be installed inside of the home, including: sump pumps, battery back up sump pumps, drainage systems, and so on. However, this kind of basement problem typically is an indication that moisture from outside the home is causing the problem. This can be taken care of with exterior waterproofing systems. Wall cracks outside of the home may need to be patched or filled with an epoxy or polyurethane material. This will prevent moisture form being able to get inside the home.
Once the leaks have been found and taken care of, the surface of the walls can be sandblasted, as mentioned above. Unfortunately, the abrasiveness of this type of cleaning may lead to additional holes or cracks in the wall. As an alternative, you could use special chemical cleaners to remove the substance from the wall. You will need to pre-soak the wall, apply the chemical cleaner, and then thoroughly wash the wall once the process is complete.
Conventional cleaners are usually one part muriatic acid and 12 parts water. When used several times to treat the wall, you should notice that the white, flaky substance is getting lighter and lighter until it is eventually removed completely from the wall's surface.