Garage floors are generally paved with concrete; luckily, sealing and painting a concrete garage floor isn't difficult. Special masonry paints can be used on concrete. For the best, longest-lasting results, always seal, prime, then paint your concrete floor. This is especially true for high-use areas like the garage.
Remove all the contents from the garage and vacuum the floor. Vacuum the corners, the area around the garage door, and across any baseboards, if applicable.
Mix up a bucket of TSP and water according to the manufacturer's directions. TSP is a cleaning solution that will remove any grease, oil or similar build-up on the floor. Don't skip this step; any oil in the concrete will seep through the paint and ruin the finished job.
Apply a good-quality concrete or masonry sealer with a roller brush and extension rod. Most sealers are easy-to-apply clear liquids, so it should go on quickly. Allow to dry completely.
Prime the garage floor with a concrete primer, using the roller. Although this step can be skipped if a masonry paint with built-in primer is used, it's still a good idea to give your garage floor this extra layer of coverage.
Add floor texture to the paint, if desired, and paint the entire garage floor surface. Floor texture provides a touch of "grit" so the floor won't be slippery when wet. When you paint, start around the edges and work your way out the open garage door. Apply two coats for the best coverage.
Apply a topcoat of sealer, if desired, using the roller This will add a layer of protection to your paint if your garage is especially high-traffic.