How to Paint Basement Cinder Block Walls

Mix a solution of warm water and two squirts of dish detergent into a bucket. Dip a soft-bristled brush into the cleaning solution and scrub the cinder walls, removing dirt and grime embedded into the concrete. Rinse the walls after cleaning with warm water and a sponge and allow to dry completely.

Acid etch the cinder blocks before painting. Put on rubber gloves, boots and goggles. Add one part muriatic acid to three parts water in a bucket. Apply the acid mixture to the cinder block walls with a stiff-bristled brush. The muriatic acid bubbles on the concrete. Rinse the walls with a garden hose or a bucket of water and a sponge after the bubbling has ceased. Allow the cinder blocks to dry completely.

Vacuum the cinder block walls with a sweeper attachment after the walls have dried. The acid etching leaves white residue that needs removal before painting.

Apply primer to the cinder walls. Pour primer into a paint pan and roll onto a paint roller or paint brush. Wipe primer onto the cinder block walls using up and down strokes. Allow the primer to dry before applying the paint.

Pour waterproof paint into a clean paint pan. Roll paint onto the roller or paint brush and apply to the cinder walls. Paint the walls generously, making sure to get into tiny crevices of the cement. Allow to dry and apply a second coat. Cement is porous so you may need a third coat to achieve the desired color.