How to Tank Damp Walls

Dry off damp walls with microfiber towels. If necessary, set up large fans to blow against the walls for at least one day. Once dry, carefully remove debris, old plaster, paint and loose pieces using 40- to 60-grit sandpaper.

Mix salt neutralizer in the proper amount of water determined by the product instructions, and spray on the wall with a spray bottle. The neutralizer removes traces of salt, which enhances the sticking action of the tank slurry. Allow it to dry.

Mix the cement slurry according to the manufacturer's directions. Add a replastering additive to it. The amount required is based on the amount of slurry you’re mixing. Stir all the ingredients together with a wooden spoon or stick until the slurry is thick and smooth.

Apply the cement slurry in horizontal strokes to the wall with a 3-inch wide paintbrush. Allow it to dry. Apply a second coat in a vertical motion. Once dry, you have a tanked wall, which can then be plastered or painted.