Transforming a dull, stained concrete garage floor into a sleek, durable surface is easier than you might think. Epoxy coating enhances your garage’s appearance and gives it a hardwearing, stain-resistant finish. This Old House host Kevin O’Connor teams up with epoxy-coating expert Doug Fasching to demonstrate the process.
What Are Epoxy Coatings?
Epoxy coatings consist of two main components: a resin and a hardener. They form a tough, plastic-like material that adheres strongly to concrete surfaces when mixed.
These are the three basic types of epoxy coatings you can buy:
- Water-based epoxy: This type is easier to apply but less durable than other options.
- Solvent-based epoxy: Solvent-based epoxies offer better adhesion and durability, but they give off strong fumes.
- 100% solid epoxy: This is the most durable option, and putting it on is best left to the pros.
How Epoxy Works: When the resin (Part A) and hardener (Part B) are mixed together, long chains of molecules form a tight lattice, each one branching out with many arms to connect with other molecules, until they form a “permanently cross-linked polymer”—a dense, solid plastic. This curing process can last for days, long after the epoxy appears to have dried.
Preparing the Garage Floor for the Epoxy Coat
Before applying the coating, you’ll need to prepare the concrete and ensure it’s clean, dry, and porous for good adhesion.
Assessing the Concrete
Before beginning, it’s essential to check the condition of your concrete floor. Doug demonstrates how to test the floor’s porosity by spraying water on the surface. If the water beads up or doesn’t absorb quickly, there may be a sealer present that needs to be removed before applying epoxy.
Pro Tip: As TOH Magazine notes, “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 the etching solution doesn’t foam — in that case, you’ll need to strip the sealer with a chemical stripper or a specialized machine before proceeding.
Cleaning and Degreasing
Start by sweeping the entire floor to remove loose debris. Then, spray some water on the concrete and note “problem areas” where it doesn’t soak in. Apply a biodegradable degreaser on these problem areas, and scrub it in with a long-handled brush. Rinse thoroughly with a garden hose.
Etching the Surface
Next, you’ll need to etch the concrete. This creates a porous surface that lets the epoxy bond effectively.
Acid etching using powerful chemicals was the method of choice for a while, but many professionals no longer recommend it since it isn’t always consistent, can damage concrete slabs, and carries harmful risks to health and the environment. Instead, consider using a mechanical grinder to do the job.
Repairing Cracks and Holes
For a clean finish, address existing imperfections on your concrete floor before you apply the coating. Clean minor cracks thoroughly with a wire brush and apply an epoxy crack filler to patch them up. For larger holes or spalling, remove loose concrete, apply an epoxy patching compound, and let it cure completely before you continue.
Pro Tip: TOH general contractor Tom Silva recommends two-part epoxy formulations for patching: “I usually go with 2-part epoxy formulations because they’re extremely durable and have compressive strengths greater than the concrete itself. You have to protect your skin and ventilate the work area, but once cured, the stuff’s inert.”
Applying the Epoxy Coating
Once the floor is prepared and dry, you’re ready to apply the epoxy coating.
Mixing the Epoxy
Epoxy coatings typically come in two parts that must be mixed right before application. Combine the resin and hardener according to the manufacturer’s instructions, mix thoroughly for about 3–5 minutes, and let the epoxy sit for 30 minutes before applying it.
Remember that many epoxies only have a pot life of 2 to 2 ½ hours. Be careful not to mix more than you need, or you may find yourself out of coating.
Pro Tip: During a TOH project, contractor Doug demonstrated the mixing process and advised letting the can sit for 30 minutes after combining the two parts: “The can may feel warm to the touch as the chemicals react with one another.” He also emphasized that once mixed, you need to move efficiently: “The epoxy has 2 to 2.5 hours of pot life. That’s why we don’t want to mix up any more than we need to ahead of time.”
Applying the First Coat
First, apply a coating to the edges of your garage with a 3-inch paintbrush.
Then, it’s time for the floor surface. Pour a ribbon of epoxy onto the floor and spread it with a roller attached to an extension handle. Work in sections about 2 feet deep by 6 feet wide. Use finishing strokes perpendicular to your initial application for even coverage.
Let the epoxy dry overnight before you apply the second coat.
Adding the Second Coat and Color Flakes
The second coat provides additional protection, helps the result look more consistent, and allows for the addition of decorative color flakes.
Mix and apply the second coat following the same process as the first coat. If you’re using color flakes, apply them while the epoxy is still wet. Work your way across the floor, making sure the flakes are evenly distributed.
After applying the final coat, let the epoxy cure for 24–72 hours before using the garage. Keep your garage well-ventilated for uniform, proper curing.
Budgeting for Your Epoxy Project
Depending on where you live, coating a garage can cost $1,599–$3,393.
Material Costs
Epoxy kits vary in price, depending on the type and quality:
- Water-based epoxy kits: $30–$50 per gallon
- Solvent-based epoxy kits: $50–$100 per gallon
- 100% solid epoxy kits: $75–$150 per gallon.
Professional Application
If you opt for a professional application, labor costs can range from $50–$150 per hour or $4–$7 per square foot.
All cost data sourced from Angi.
