Repainting a garage floor is a fairly straightforward process and a job that most homeowners will have to tackle at one time or another. As most garage floors are made of concrete, epoxy is the most common type of paint used for this project. Epoxy paint resists grease and oil, which can stain your garage floor. It also happens to be a very easy surface cover to clean.
Feather sand your floor. Using a standard handheld sander, go over any spots that have loose or peeling paint.
Clean your garage floor thoroughly. First, use a stiff-bristled broom and give the floor a good sweeping. Then, using a spray bottle, spray some bleach cleaner on any oil or grease stains. Once the bleach begins to penetrate the surface of the floor, in about five to 10 minutes, use your broom to scrub each stain.
Rinse your garage floor. If all it needs is a solid rinsing, then your standard garden hose will work fine. However, if you still have some stubborn stains, you may want to consider renting a power washer to help loosen them up. (Power washers are readily available in any large hardware store.) Repeat this process as often as necessary until the floor is stain-free. Let the floor dry overnight.
Fix any cracks in your garage floor. While this is not an absolutely necessary step in the painting process, it is the best time to tackle this job. For minor cracks you can simply purchase some concrete compound, which is similar to caulking. Squeeze it into the cracks and you're done. If you have larger damage you may need concrete patch materials. Both of these items should be easily found in your local hardware or home improvement store. Once you have repaired the cracks, be sure to let the floor dry completely.
Prepare your paint. If you are using an epoxy paint, you'll need to mix it according to the manufacturer's directions, as there can be a slight difference among paints. The mixture depends on the size of the garage floor you are going to paint. Whether you are using epoxy or a standard concrete paint, pour the paint into a standard paint tray to begin painting.
Use a roller with a long handle attachment to apply the paint to your floor. Always roll on paint in a W shape to avoid unsightly track lines in the finished paint job. You'll need to cut in around the edges and corners with a brush, as rollers cannot get into tight spaces.
Wait a full 24 hours before applying a second coat. Once the painting is done, you'll need to keep cars off of it for three to five days to make sure the paint is completely dry.