How to Waterproof Exterior Walls for Water Damage

Many times, basement walls are constructed out of cinder blocks. The blocks are durable and strong enough to support your home, but they are also porous, allowing water to seep through when the ground is extremely wet. This can be a problem if you're planning on finishing the basement, or if you store valuable items that can be damaged by excessive moisture. Waterproofing the walls can prevent water damage from occurring.

Power washer
Hammer
Chisel
Patching compound
Putty knife
Urethane caulk
Foam backer rod
Waterproofing agent
Paint brush

Instructions

- 1
  Spray the wall with a power washer to clean it. Allow it to dry overnight.
- 2
  Patch cracks in the wall by chiseling away at the area around the crack until you get to the bottom of the crack, then fill it with patching compound. Smooth the patching compound with a putty knife, and allow it to dry for the time specified on the packaging.
- 3
  Patch the cracks at the bottom of the wall where it meets the floor. Run a thick bead of urethane caulk over the crack if it's a quarter-inch wide or smaller. If it's larger, insert the foam backer rod into the crack, then apply the urethane caulk. Smooth the surface of the caulk. If you have a floating slab basement, which contains a trench around the entire floor, do not patch this trench.
- 4
  Cover the walls with a waterproofing agent. Apply the waterproofer to one block at a time with a paint brush, spreading the waterproofer in every direction to ensure complete coverage. Let the first coat dry, then add a second coat.

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