If you have white crystals accumulating on the surface of your concrete, you most likely are the victim of efflorescence. Efflorescence is very common on bricks and cinderblock, and on concrete, or any substrate, that has moisture issues. Efflorescence is not only an eye-sore, but a problem that continues to reappear.

If you have every cleaned efflorescence off of concrete with water (and even some chemicals), you will notice that the efflorescence reappears in anywhere from two weeks to two months. This is because that while the existing efflorescence has been removed, the cause of the efflorescence has not been dealt with.

According to Concrete Contractor, “Efflorescence is caused when soluble salts and other water dispersible materials come to the surface of concrete and mortars. It’s induced by low temperatures, moist conditions, condensation, rain, dew, and water added to the surface of fresh concrete to assist troweling. It can occur very soon after exposure to moist or cool conditions or gradually, especially when it comes from within the concrete or from the subgrade.”

How to Clean Efflorescence

First, you want to use a cleaning chemical such as the Armor ER100. It is always important to follow the instructions that come with the cleaning chemical being used as these are just guidelines.

PREPARATION: Always test the surface to be prepared for previous coatings. This product will not work properly over coated concrete surfaces and is not to be used as a chemical coating stripper. It is always recommended to test Armor ER100 prior to application for proper dilution rates, application coverage rates, and simply to ensure there are no issues with compatability.

Protect all areas not to be cleaned and prepared. Mask off all adjacent surfaces with painter’s tape or plastic duct tape. Use a plastic or coated cardboard as a spray shield. Plastic or polyethylene sprayers and buckets are recommended for application.

MIXING: Dilute material with water to desired dilution rate. Pour cold water into mixing pail, then add Armor ER100. Do not mix with warm or hot water.

APPLICATION: Pre-wet the surface to be cleaned. Using a acid-resistant polyethylene pump-up sprayer, apply diluted material to the surface. Work in small areas, covering the entire working surface not leaving dry areas or spots. Overlap sections prior to moving on to remaining areas. Allow 5-10 minutes for proper reaction, then by use of an acid resistant brush, work cleaner into the surface. Rinse thoroughly with water. Re-peat until floor is clean and free of all material. When possible, high pressure 500-1000 psi rinsing is recommended for best results. Make sure a final rinse of a water/ammonia blend solution to neutralize the surface for proper pH level is applied. Remove standing water with a wet vacuum.

Clean all equipment and tools with a warm soap and water solution. Allow the area to dry 18-24 hours to make sure the surface is bone dry and prepared for most any stain or coating application.

How To Stop Efflorescence

The best way to reduce efflorescence is to slow down the movement of water and moisture through the pores of the concrete. That can be done with a few different products:

• Silicate Densifiers: Silicate concrete sealers chemically react to form a hardened crystalline barrier within the pores. Through densification, the movement of water, moisture, and efflorescence will be reduced. View Best Concrete Densifiers.
• Epoxy Primer Coatings: High solids epoxy coatings are designed to reduce or stop moisture, therefore reducing the movement of efflorescence through concrete. View Best Epoxy Coatings.