How to Use Waterproof Paint in a Wet Basement

Dry out the basement before you begin painting unless you’re using a waterproof paint that can be applied to damp surfaces.

Remove old paint and loose mortar with a stiff brush. Go over the walls with the hose attachment on your vacuum cleaner to remove any remaining debris in the cracks and crevices. Vacuum thoroughly where the walls meet the floor.

Apply the paint, following the manufacturer’s instructions for the recommended spread rate. Use a paint roller on smooth surfaces like finished concrete and a large brush on rough surfaces like masonry.

Paint up to a natural stopping point like a corner of the room if you won’t be able to finish the project in one session. This will keep a wet edge, and you’ll get a more even look if there are no spots where you’ve applied wet paint over dry.

Work the waterproof paint into imperfections in the masonry with the brush. Check for pinprick-sized holes on the surface of the paint and apply more paint to cover them. Wait a few days while the paint dries completely.

Apply another coat of paint if there are still signs of water seeping through the walls.