Epoxy Paint Shop Floor: Achieve A Showroom-Quality Surface In Just Three Days.

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This article is from Issue 54 of Woodcraft Magazine.

Achieve a showroom-quality surface in just three days. 

By Gary Lombard with Jim Harrold
Consultants: Rust-Oleum

Whether in a garage (shown here), basement, or dedicated outbuilding, concrete floors for home shops are the norm, far exceeding the number of wood floors. And while concrete provides a flat surface on which to roll mobilized tools, it can absorb drips and spills from motor oil, woodworking stains, and other liquids. Another problem: Smoothly troweled or sealed concrete can prove slippery when coated with fine sawdust. Beyond that, its look is not all that great. To remedy these issues, consider laying down an attractive two-part epoxy paint and sealer on your concrete that lets you easily wipe up spills, sweep up dust, and provide a sure grip underfoot. Plus, when you do the installation yourself, big savings are in store.

To properly follow through on the prep and installation for the featured workshop in this issue, I and Jim Harrold teamed up with the experts at Rust-Oleum to lay down a tough two-part epoxy paint (EPOXYSHIELD Professional Floor Coating Kit) and sealer (EPOXYSHIELD Premium Clear Floor Coating Kit), capturing the steps from beginning to end. The resulting showroom-quality surface promises a lifetime of wear-resistant good looks.

In all, the work took one full day for prepping, two-thirds of a day for painting and adding the decorative color chips (for a terrazzo-like appearance), and two hours on the third day for rolling out a sealer containing a nonslip additive. Full cure takes at least three more days.

Tools for the Job

From prepping to painting to final sealing, laying down a two-part epoxy paint and sealer on a concrete shop floor requires a few common tools. These include a good scrub brush, five-gallon bucket, plastic watering can, floor squeegee, chemical/liquid-resistant latex or rubber gloves, eye protection, paint-mixer attachment for a cordless drill, roller pan, pan liners, an epoxy-safe 1⁄2"-nap paint roller, roller extension handle, and a 3" utility nylon paintbrush.

Test the concrete

Before buying a two-part epoxy floor paint kit, analyze the condition of your concrete to see if it meets the requirements and to determine the prep work approach. Moisture in the slab, a previously applied sealer, a poorly bonded painted surface, poorly cured spalling concrete, and oil stains all pose adhesion problems for epoxy paint. Some can be fixed; some can’t. Let’s deal with these one at a time.

Remove the plastic sheeting to see if water beads cling to the bottom face, or if a dark shadow appears in the concrete–both telltale signs.
Pour water onto the concrete to see if it is absorbed or if it sits or beads on the surface. If the water sits, the concrete is sealed.

Moisture

Certainly, if the concrete contains moisture, you shouldn’t paint it. To test for moisture, tape a 3 × 3' piece of 1 mil plastic sheeting to the floor and let it sit for 24 hours. Then peel it up, as shown in Photo A.

Sealed surface

To see if the concrete is sealed, conduct the test in Photo B. If the test proves positive, grind the surface to remove the sealer.

Unsealed surface

If the concrete proves unsealed, chemically etch the surface to clean it. (With newly poured dry concrete, skip the grinding and etching steps, provided the slab has been allowed to cure for a minimum of 28 days before coating.)

Painted slab

To test the adhesion of an existing paint slab, incise a small X on the surface, and stick a piece of duct tape over it. Pull off the tape to see if some paint came with it. If so, the bond is suspect, and the floor will need surface-grinding to remove the paint. If the paint does not come off–meaning it is well bonded–scuff-sand and clean the surface to prep it.

Poorly cured or damaged concrete

For poorly cured or loose concrete, repair the surface with a concrete patch product, and clean it thoroughly to remove the dust. (One patch product is Rust-Oleum’s EPOXYSHIELD Concrete Patch and Repair Kit.) This two-part epoxy-based patch dries fast, resulting in an extremely hard surface. If surface erosion resulting in excess concrete dust and spalling persists–even after cleaning–do not paint the floor.

Oil stains

Motor oil drips and stains from autos, lawn mowers, or other sources create areas on a concrete floor that resist adhesion. Dispense with the problem as explained under “Day 1: Prep the Surface.”

Using EPOXYSHIELD Heavy-Duty Degreaser, scrub stained areas with a stiff bristled brush. Rinse clean.

Day 1: Prep the surface

Once you have established that the floor is a candidate, follow through with the appropriate strategy, keeping in mind that preparation is critical to a well-bonded epoxy paint job. With an existing (versus new) concrete floor, patch any holes, cracks, or chipped areas with a nonflexible concrete patching product (found at home centers).

For oil stains, scrub the surface, as shown in Photo C. After, use the same scrubbing approach to etch an unsealed floor.

To etch an unsealed floor, mix up a solution of one part phosphoric acid to four parts water in a plastic watering can. Pre-wet the floor, and then, working from back to front, scrub the entire surface in manageable 10 × 10' sections. It should fizz slightly from the chemical reaction. When the fizzing stops, rinse the surface clean. Rinse and scrub the floor three times to achieve the cleanest possible surface, one that is free of all dirt and contaminants. For best results, use a foam or rubber floor squeegee to remove the rinse water from the surface. Let it thoroughly dry for 24 hours.Be sure to wear eye protection and gloves when prepping and cleaning the floor with chemicals.

Grind the sealed floor along the walls with an industrial-grade orbital sander and 60-grit discs.
Abrade the open floor with the floor grinder, working in one direction; then cross-grind at 90°.

To prep a sealed floor, sand the surface with an industrial orbital disc sander and a floor grinder having 60-grit abrasive stones. Rent these for about $100, and use them as shown in Photos D and E. Wear a dust mask and hearing protection, and use a shop vacuum to gather floor dust. Open all doors and windows, and use fans to exhaust dust-filled air to the outside. Vacuum the floor several times for the cleanest possible surface, and wash it.

Because constant daily sunlight will cause a two-part epoxy coating to yellow and degrade, plan the floor coating to align with the inside edge of the garage door. To do this, mark and lay down strips of duct tape along the line to establish the border between the driveway and garage/shop floor. Note that if you leave the garage door open and regularly expose the floor to sunlight, the epoxy coating will become damaged over time.

Day 2: Mix and apply the epoxy paint

Ensure that the workspace is properly ventilated and that the room temperature is between 55 and 90 F°. Turn off pilot lights to any nearby hot water heater, furnace, or other source of ignition. Pour part B into a five-gallon bucket, and then pour in part A, blending the parts as shown in Photo F. A two-gallon mix lets you do a 300-square-foot space or about a one-car garage. On larger floors, mix larger quantities of the A parts and B parts separately, and then mix equal amounts of the parts together when you are ready to continue covering the floor. This guarantees that the color remains consistent across the floor. After mixing, allow the ingredients to sit for 30 minutes in order for them to chemically combine.

Mix the two parts of the epoxy paint for 3 to 5 minutes using a paint-mixer accessory (found at home centers) and a cordless drill.
Use a brush to cut in 4"-5" from the wall in 4'-long bands while working out of a small paint pot.

Roll out the floor in a manageable 4 × 4' patch with a solvent-resistant paint roller having a 1⁄2" nap and plastic core.

Broadcast chips by the handful over the painted area with an underhand motion, letting them float down and blend in evenly.

Ideally, coating the floor with epoxy paint and chips is a two-person job–one to cut in along the walls and broadcast the chips and one to roll out the floor. Don’t expect to take a break. Following the 30- to 60-minute induction process, depending on the air temperature (see instruction sheet for more information), you have just 90 minutes to apply the mix.

Begin painting by cutting in 4' along the corner walls, as shown in Photo G. Next, roll out a 4 × 4' section in the same area, as shown in Photo H, working toward a door opening as an exit strategy.

Before moving to the next section, toss the decorative color chips up and away from you so they land flat on the wet paint film. You want the chips to be distributed evenly onto the painted surface, as shown in Photo I. Determine the level of chip coverage for the look you want (Photo I Inset). Repeat until you’ve painted the entire floor and dispersed the chips. Let the floor cure for 24 hours. Be careful to contain chips in each painted section as you work so you don’t get any on the roller or unpainted surface.

Coat the two-part epoxy painted floor with a protective, slip-resistant sealer using a clean roller and working in manageable sections.

Day 3: Roll on a slip-resistant sealer

Before sealing the painted floor, mix in the slip-resistant ingredient (EPOXYSHIELD Anti-Skid Additive) into the sealer (EPOXYSHIELD Premium Clear Floor Coating). Now, as before, cut in with a brush and roll out the floor with the sealer, as shown in Photo J, following the precautions mentioned earlier. Let the sealer cure for at least 24 hours before walking on it. Do not drive on the surface for another three days to allow for a complete, undisturbed cure.  

Costs and Savings

To paint and seal this garage floor, a 600-square-foot area, we used two EPOXYSHIELD Professional Floor Coating kits (four gallons total), three EPOXYSHIELD Premium Floor Coating Kits (as the sealer), a rented grinder and orbital sander, rollers, brushes, and miscellaneous materials for a do-it-yourself cost under $600. To have the floor professionally done would cost about $2,000.

Special thanks to Don Evans, Mike Ortiz, Robert Shoenberger, and Brendan Steidle at Rust-Oleum for serving as technical consultants during the floor installation. For more on the products featured here, visit rustoleum.com or call (888) 683-5667.

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