How to Treat Wet Basement Walls

Updated November 21, 2016

Wet basement walls are a source of concern. Constant moisture is a breeding ground for mould, mildew, and bacteria. Basement walls are either constructed out of poured concrete or concrete blocks, which are porous. Over time the pores allow water to seep back through the walls. This can occur for any number of reasons, such as house-settling, clay soil that retains water, foundation cracks, and flooding. The best solution is to repair the source of the problem, but some repairs can cost thousands of dollars. For do-it-yourselfers, sealers provide a barrier and will stop moisture from seeping through the walls.

Wipe down the walls with old rags or towels. Set fans around the basement and allow them to run enough so that the walls are as dry as possible. This will provide a better bonding surface for the epoxy sealer.

Mix a solution of one part base to one part epoxy resin in the 5-gallon bucket. Use a variable-speed drill to thoroughly mix the components. Follow the manufacturer's instructions on how much product to mix based on the square footage of the basement. The epoxy product must be used within a five- to six-hour window. Allow the mixture to set undisturbed for at least 15 minutes.

Apply sealer at the floor and at the ceiling of the basement walls, using a 4-inch brush. Brush on the sealer in the same manner that you would brush on paint.

Place the roller screen into the bucket of mixed epoxy and use the roller to cover-coat the wall. Repeat steps 3 and 4 for each wall. Allow the walls to dry overnight.

Repeat steps 2, 3, and 4. A second coat will cover any areas that may not have received a good cover coat during the first application.


Check the day time and nighttime temperatures and the overall temperature of the basement before beginning the project. For an epoxy sealer to effectively set, the temperature cannot be below 4.44 degrees Celsius, and is best applied at temperatures over 10 degrees C.

Things You'll Need

  • Fans
  • Rags
  • Variable-speed drill
  • Mixer bit
  • 5-gallon bucket
  • 4-inch natural bristle paintbrush
  • 9-inch lamb's wool roller
  • 5-gallon bucket roller screen
  • Non-porous epoxy sealer
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About the Author

Based in Oklahoma City, Debbie Tolle has been working in the home-improvement industry since 2001 and writing since 1998. Tolle holds a Master of Science in psychology from Eastern Illinois University and is also a Cisco-certified network associate (CCNA) and a Microsoft-certified systems engineer (MCSE).