If you are tired of looking at the dreary grey colour of a concrete wall, consider painting it. A couple of coats of paint will work wonders to spruce up your room or outdoor space. A concrete wall must be properly prepared prior to painting. Failure to do so may result in the paint not adhering properly.
Apply a concrete patch to any holes or cracks. Run a putty knife back and forth over the area to smooth out the patch. Allow the patch to dry thoroughly according to the manufacturer's instructions.
Mix a solution of a 1/4 cup of trisodium phosphate and one gallon of warm water in a bucket. Use a sponge to wash the walls with the trisodium phosphate solution. Work from the bottom of the wall towards the top, and rinse and wring out the sponge often. Allow the walls to dry completely before proceeding.
Apply a coat of concrete latex primer to the wall. Pour the primer into a paint tray with a liner and use a 3/8-inch nap roller to apply the primer. Overlap your roller strokes to ensure no area of the wall is missed. Allow the primer to dry completely before applying paint.