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How waterproof basement walls inside

Keeping your basement dry can be especially challenging, particularly with heavy rainfall or with the arrival of spring. Apply a waterproof sealant to the inside of the basement walls can alleviate many problems related to moisture. Placing this sealant is as simple as paint roller; however, it takes a lot of work to prepare the walls for sealing. With the right tools, you can waterproof your basement walls in a weekend.


  1. Remove all loose paint, concrete, dust and other similar elements of the walls with a metal bristle brush. Brush in deep areas surrounding any breakage or penetration to prepare for hydraulic cement.
  2. Clean the walls with a concrete cleaner degreaser. Follow the manufacturer’s instructions for mixing the cleaner. Apply with a sprayer to accelerate the process. Brush the walls with the swab to remove fat deposits and other impurities. Rinse the wall and let it dry as directed.
  3. With chisel, remove chunks of concrete that are broken or loose holes in walls. Use chisel to trim the edges thereof to allow the hydraulic cement join.
  4. Mix small amounts of hydraulic cement following the instructions. Place the cement in the cracks and holes and be sure to seal completely. Smooth the surface of the concrete with a trowel until it is flush with the surface of the walls. Let the cement dry as instructed.
  5. Applied with a roller tray thick bristles and paint primer, if necessary, Make sure you get to the corners of the walls and the area around the repair. Let it dry and if necessary apply a second coat.
  6. Waterproof inner walls by applying the sealant with a roller. Make sure the repaired areas are properly sealed. The same should happen with the edges and corners. Let the sealer dry according to instructions. Apply a second coat if necessary.

Tips & Warnings

  • Before waterproofing the inside walls of your basement, make sure that humidity is an external problem. Tape a piece of plastic with a damp spot on the wall. The next day inspect it to see if moisture is the side facing the wall, indicating a problem of external moisture, or the area exposed to air, indicating a problem of interior moisture.
  • Use eye glasses when brushing, clean and use the chisel on the wall. Make sure the area is well ventilated before applying the sealant.