How to Remove White Stains and Mold from Basement Walls

White stains and mold on your basement walls are both caused by moisture. The white marks, which often look like chalk, are actually called efflorescence. Efflorescence is caused by minerals in the water that could not evaporate along with the water on the basement wall. Similarly, mold is found in wet environments, and will thrive if not checked.

Step 1: Remove any white stains from your concrete basement walls first. Fill a spray bottle with white vinegar and saturate the basement wall with white vinegar. Use a scrub brush to agitate the wall, removing the efflorescence. If the white stains are not easily removed, saturate the area again and wait a few minutes. Then try to remove the white stains with your scrub brush.

Step 2: Rinse the concrete basement wall with water and a sponge, making sure to remove all of the white vinegar.

Step 3: Turn on a fan and keep the air circulating within the basement until the walls are dry.

Step 4: While the walls are drying, remove any porous material that may be infected with mold. Clean these materials or discard them as necessary.

Step 5: Apply a mixture of one part bleach to nine parts of water to the basement wall using a scrub brush. Scrub vigorously until you have removed any visual signs of mold.

TIP: The bleach mixture will splatter: plan on wearing clothing that you don't mind staining during this step. Also wear eye protection and rubber gloves and keep the area well ventilated while working.

Step 6: Rinse the surface of the basement wall with a sponge and water.

Step 7: Turn on a fan to encourage the entire basement to dry completely. Open all doors and windows to aid this process. Once the basement walls have been completely dry for 24 hours you can proceed.

Step 8: Apply a coat of concrete sealant to the surface of the basement walls using a paint roller. You can use a brush to cut in around areas that a roller cannot reach. Allow the concrete sealant to dry completely before attempting to paint or otherwise alter the basement walls.