Things You'll Need
Electric floor scrubber
Stiff push broom
Concrete patching compound
Low-nap roller covers
Paint pan liners
Deep paint pan
Color flakes (optional)
Take your vitamins before you paint a concrete floor with epoxy paint; the job is labor intensive. You have to prepare the floor properly to ensure the paint adheres, so roll up your sleeves, because there's a lot of work to do before you can paint. Clean the floor, repair the cracks, etch the floor, then clean it again. The prep work is the most critical part of the process, so don't skip it or you likely will have peeling paint to repair later.
Perform a moisture test on the floor to determine if the concrete should be painted. Secure a sheet of plastic to the floor with painter's tape. Check the plastic for condensation after 24 hours. If there is condensation under the plastic, the floor shouldn't be painted until the source of the moisture is discovered and the issue is resolved. Proceed to Step 2 if the concrete is dry.
Mask the bottom edge of the walls above the floor using wide painter's tape. Apply plastic sheeting to the walls above the tape and garage doors. Secure the top and bottom of the plastic with tape. Open the garage doors to gain access to the floor.
Sweep dirt and debris from the floor. Remove oil or grease stains with a degreasing cleaner. Use an electric floor scrubber to clean the floor, or scrub the floor using soapy water and a stiff push broom. Remove dirt from the edges of walls or in corners with a scrub brush. Rinse the floor with water from a water hose. Use a long-handled squeegee to push the standing water into pools, and remove the water with a wet-dry shop vacuum.
Put on safety glasses, gloves, a respirator and rubber boots.
Prepare an etching solution of 1 part muriatic acid to 10 parts water and pour it into a watering can. Add acid to water when you mix the solution, not water to acid.
Wet the floor with water from a hose.
Pour the etching solution onto a manageable area of the floor, in the farthest corner from the exit door. Use the bristled push broom to scrub the floor. Vigorously scrub the floor in one direction, then repeat the process in the opposite direction. Continue etching the floor in manageable sections until it has been completed. Rinse the floor with a garden hose until the water runs clear. Use the wet-dry vacuum to remove the water. Allow the floor to dry for 24 hours.
Fill holes and cracks in the floor with concrete patching compound, using a scraper. Allow the compound to dry completely. Use a medium-grit sanding block to sand and smooth the patched areas. Remove the sanding dust with a vacuum.
Clean the floor a second time as outlined in Step 3 and allow it to dry completely.
Follow the manufacturer's instructions to mix the activator with the epoxy paint. Allow the mixture to sit for the amount of time recommended by the manufacturer. Mixing instructions vary among products.
Insert a low-nap roller cover onto a roller handle, and attach a paint pole to the handle. Insert a paint pan liner into a deep paint pan, then fill the pan with paint.
Cut in the perimeter of the floor with paint, using a 3-inch paintbrush. Wrap the paintbrush in plastic when the floor has been completely cut in. Submerge the roller into the paint, and roll it back and forth over the grid lines to distribute the paint evenly. Start painting in the farthest corner from the door and work out toward the exit point. Roll the paint onto a manageable section of the floor; the size is adjustable, depending on how fast you paint. Don't make the section so large you can't complete it before the paint dries. Use long, smooth rolls to fill in the section with paint. Roll over the cut line to blend brush strokes. If you are using color flakes, randomly toss the flakes into the wet paint after completion.
Move to the next section and repeat the process. Continue painting the floor in manageable sections to maintain a wet edge, until the floor has been completed. Clean the paintbrush with paint thinner and allow the floor to dry for 24 hours. A second coat of paint can be applied; distribute the color flakes in the second coat of wet paint.
Stir the clear top-coat sealer with a paint stick. Insert a new paint pan liner into the paint pan and a new low-nap roller cover onto the roller. Fill the pan with sealer and follow the procedure outlined in Step 12 to apply sealer to the floor in the same manner the paint was applied. Ensure the floor dries for 24 hours before allowing foot traffic, or three days for automobile traffic.
You can use a pre-mixed etching solution in place of muriatic acid.
A 5-gallon bucket and a paint grid screen can be used in place of the paint pan, but the pan is cleaner and easier to use.
Preference of the rolling pattern vary among painters. You can use either the "W" pattern or straight line rolling method provided the paint is smooth and uniform.
Add sand to the epoxy for a non-skid floor finish.
Allow new concrete to cure for a minimum of 30 days before you paint.
Epoxy paint emits fumes; use adequate ventilation when you paint.
Solvent-based products are not volatile organic compound compliant in all areas. Check with your state air regulatory agency for rules applying to solvent-based primers and paints.