Painting lines on concrete can provide decorative elements to your driveway, garage or basement. Lines could also form a basketball court, mark parking spaces or indicate other areas on a concrete surface. Painting on concrete is a straightforward task, but it does require a few more steps than painting other surfaces. Properly prepping the surface will prevent the paint from cracking and peeling with moisture and wear.
Mix trisodium phosphate (TSP) with water according to the package instructions. Find this strong cleaning solution at any hardware store. Dip a scrub brush in the solution and wash the concrete vigorously. Allow the concrete to dry overnight.
Put a scoop of concrete patch onto a putty knife. Spread the paste across any cracks in the concrete. Smooth with a putty knife. Let the patched area set for four hours, or according to package instructions.
Check the concrete for moisture. Set a piece of cling film on the ground or wall. Tape it down on all four sides with masking tape. Moisture is less of a problem for walls than floors, but still a possibility. Let it sit overnight. Moisture underneath the plastic will indicate that the concrete has not been sealed. Apply a coat of concrete sealer to the unsealed concrete.
Apply masking tape to the concrete to mark out the lines you want to paint. Use three-inch tape or larger.
Pour the primer into a paint pan. Move the roller through the primer to saturate the pad. Roll the roller in the shallow portion of the pan to remove excess paint. Apply primer to the taped areas. Roll a thin coat of primer between the tape lines. Allow the first coat to dry. Apply a second coat of primer.
Paint the concrete with the roller brush in your chosen colour with the same technique used to apply the primer. Apply two to three thin coats of concrete and masonry paint for the best finish. Allow each coat to dry before applying another. Allow the paint to dry overnight.
Roll on a coat of concrete sealer. Sealer will help to protect the painted finish and prolong its life. Let the sealer dry.
Pull up the masking tape. Hold the tape at a 45 degree angle and pull slowly.
Exterior concrete will be exposed to rain, snow and sun. Expect to reapply paint every three to five years to exterior concrete.