How to Epoxy-Coat a Garage Floor

Epoxy not only tops off the pro look of a garage but also resists oil stains, beads water, and wipes clean.

By Jennifer Stimpson of This Old House magazine.

You finally got the tools hanging neatly on an outlined pegboard, and all the paint is organized in carefully labeled cabinets. But now your car is jealous, sitting like a lump on the oily, dirty concrete slab. You still need to put the finishing touch on the garage cleanup: a colorful, shiny epoxy floor coating that will have you—and your car—feeling like you’re driving into a showroom every time you come home.

Epoxy not only tops off the pro look but also resists oil stains, beads water, and wipes clean like a kitchen counter. Color chips and custom paint colors hide annoying imperfections in the concrete, and anti-skid additives give you the grip you need on a snowy day. As This Old House technical editor Mark Powers shows on the following pages, you just need a weekend to sweep the dirt out and paint the epoxy on. Then the garage will finally be a space worth driving up to—and showing off.

Step One // How to Epoxy-Coat a Garage Floor

Floor Finish Overview.

Applying an epoxy coating to a concrete floor is as easy as painting walls, but as with painting, the success is in the prep work. Once the calculations, color choices, and cleaning are taken care of, the actual application will seem like the easiest part.

To bond well, epoxy requires an even, slightly rough, and totally clean surface. That means patching any potholes and cracks and allowing them to cure fully. Concrete must be at least 60 days old and not sealed for the epoxy to adhere. You can tell if your floor already has a sealer if water beads on it or if you get to Step 2 in this process and the etching solution doesn’t foam; if that’s the case, you’ll need to take off the sealer with a chemical stripper or a special machine. (Painted floors can be re-coated if there’s no peeling.)

Stripping the floor, however, does not clean it. Any grease or dirt will compromise the epoxy adhesion, so cleaning and etching is a step that should not be rushed. Different manufacturers offer different types of cleaners, so check out the ingredients before you choose what type is best for you. Chemical cleaners vary widely, from harsh de-greasers and etchers to safer but less effective organics. You can cut down on the elbow grease by renting a machine called a floor maintainer for about $40 a day.

Epoxy coatings typically come in kits with everything you need. Once you choose one, determine if you’ll need to order extra supplies. Manufacturers may suggest two coats of the epoxy paint and top coat, but most standard kits only supply enough for one coat. If you choose to add color flakes, which will help hide concrete’s inherent imperfections, determine how heavily you’ll broadcast them across the floor so you don’t come up short. Also, if your garage’s foundation rises above grade at the bottom of the walls, you may want to consider coating another few inches up the vertical surfaces to make cleaning the garage easier. Then decide if you want to include an anti-skid additive, granules that give the finished floor a sandpaper-like surface. This may be a good option in rainy or ice-prone regions.

Once the floor is clean and ready for its coating, it all comes down to timing. Choose a day to do the work when the concrete won’t be damp from rainy weather and when the temperature is between 50 and 80 degrees; otherwise the application can bubble and peel. Then, once you mix the epoxy paint and hardener, you only have about 2 hours to work with it, so you’ll need to plan out in advance how best to paint yourself out of the garage, starting in a back corner. The hardest part is waiting: The typical drying time between each step is 12 to 24 hours. And once the whole floor is done, you still have to hold off parking the car on it for another 72 hours.

Step Two // How to Epoxy-Coat a Garage Floor

Prep and wash the area.

Using painter’s tape, stick plastic sheeting to the walls along the edge of the foundation, or at the height to which you will apply the epoxy up the walls.
Sweep the floor thoroughly to remove dirt and dust. Using an old paintbrush, dust out corners and seams. If your floor was not previously painted, skip to Step 2.

For painted floors: Using a floor maintainer fitted with a light-sanding pad, scuff the paint to de-gloss it. Sweep away the dust. Then, using a bristle broom, scrub down the surface with an all-purpose cleaner. Rinse the floor thoroughly and
let it dry for at least 4 hours. Continue with Step 3.

TOH Tip: To check if the floor is clean, stick a strip of duct tape to it once it’s dry, then peel it away. If you see any dust or particles on the tape, clean the floor again.

Step Three // How to Epoxy-Coat a Garage Floor

Etch the floor.

For new or bare concrete: Mix the etching solution with water in a plastic watering can, following the manufacturer’s directions. Make sure to wear protective gloves, rubber boots, and safety glasses when working with the chemicals.

Wet the floor with a garden hose. Pour the solution over a 10-by-10-foot area in the corner farthest from your exit point. Using a bristle broom, scrub the area in one direction, then go over it again in a perpendicular direction.

Continue etching the floor in small sections. Once you’ve finished the entire garage, rinse the floor with a garden hose, starting in your first corner and moving forward. Continue rinsing until the water runs completely clear. Allow the floor to dry at least 4 hours.

TOH Tip: Stubborn, dark discolorations may be the sign of a set-in oil stain, which will require additional scrubbing with fresh solution.

Step Four // How to Epoxy-Coat a Garage Floor

Mix up the epoxy paint.

Open both the epoxy paint and epoxy hardener cans. Begin stirring the epoxy paint, then slowly pour the hardener into it. Make sure to scrape out every last bit of the hardener into the paint.

Carefully stir the two components for 3 minutes until they are fully blended. Place the lid loosely back on the can and set it aside, away from the sun, for 30 minutes. The can may feel warm to the touch as the chemicals react with one another.

Step Five // How to Epoxy-Coat a Garage Floor

Paint on the epoxy.

Once the epoxy formula is ready, you must use it within 2 hours for it to cure properly, so work quickly. Always keep the garage well ventilated as you work.

Pour the epoxy into a roller tray fitted with a liner. Using a 3-inch paintbrush, cut in a line of epoxy around the border of the area to be covered, and paint it into seams and corners.

Step Six // How to Epoxy-Coat a Garage Floor

Roll the epoxy paint.

Move to the corner farthest from the exit. Using a 3/8-inch-nap roller fitted with an extension handle, roll a 10-by-10-foot section with epoxy paint. The epoxy should feel slightly thicker and stickier than normal house paint. Re-wet the roller and go over the section in a perpendicular direction, again feathering out uneven lines. Continue covering the floor section by section.

If you plan to use two coats, finish the entire floor, allow it to dry 12 to 24 hours (longer in humid or cold weather), then re-coat it in the same manner.

TOH Tip: Keep a wet edge as you move from section to section so there won’t be clear seams when the paint dries.

Step Seven // How to Epoxy-Coat a Garage Floor

Apply the color flakes.

As you apply the top coat of paint, stop after every section to put down the color flakes while the area is still wet.

Distribute the flakes over the area by first sprinkling them lightly, then slowly building up distribution until you have the right coating. Take a handful of flakes and shake them through your fingers the way you would sprinkle grass seed.

Work your way from the back to the front of the garage in conjunction with rolling on the epoxy. Once the entire floor is coated, allow it to dry for 12 to 24 hours (longer in humid or cold weather).

TOH Tip: While most companies package their flakes in cans with a shaker top, broadcasting them by hand may be easier to control. Practice your technique on a tarp outside the garage.

Step Eight // How to Epoxy-Coat a Garage Floor

Prepare the top coat.

Pour the hardener into the clear top coat, making sure to scrape out all of it, and stir the mixture for 3 minutes until it’s completely blended. Place the lid loosely back on the can and set it aside, away from the sun, for 30 minutes. One minute before you are ready to apply the top coat, stir the mixture for an additional minute. If you plan to use anti-skid granules, add them now.

Step Nine // How to Epoxy-Coat a Garage Floor.

Apply the top coat.

You’ll only have about 2 hours to work with the mixture. Using a clean paintbrush, cut in at corners, edges and seams. Using a 3/8-inch-nap roller, start at a point farthest from the exit and roll on the clear coat in 10-by-10-foot sections as you did with the epoxy paint. Work first in one direction. In the perpendicular direction on each section, making your way forward until the entire floor is covered. The coating will appear white or milky at first but will dry clear. Allow 24 hours drying time for foot traffic and up to 72 hours before parking a car—longer in humid or cold weather.

Thanks for checking out How to Epoxy-Coat a Garage Floor.