How to Prep a Concrete Surface for Epoxy Floor Installation

What You'll Need
Degreasing cleaner
Stiff broom and dustpan
Shop vacuum cleaner
Fiber mop and bucket
Lime powder
Moisture and alkalinity testing kits
Etching compound
Concrete primer
Long-handled roller applicator
3-inch wide paintbrush
Water or solvent-based 2-part epoxy
Non-slip additive
Vinyl color chips (optional)
Clear surface sealant

A concrete subfloor is the best surface on which to install an epoxy floor. There are several important preparatory steps you must take to ensure your epoxy floor will bond snugly with the concrete subfloor. Follow these steps below to prepare your concrete subfloor for a new epoxy floor surface.

Step 1: Remove All Furnishings and Tools from the Area

Empty out the concrete floor space completely so that nothing will get damaged while you apply the epoxy flooring.

Step 2: Test the Moisture Content and Alkalinity of the Concrete Subfloor

If your subfloor is less than 5 years old, this step is very important. Too much moisture and alkalinity in the concrete subfloor will prevent adhesion of the epoxy floor finish. It will buckle and peel off in less than 6 months. Get a testing kit at a building supply center. Set the dome on the floor, recording the weight of the calcium chloride sample before and after the test. Use 3 moisture testers for each 1000 square feet of concrete floor space where you will apply the epoxy. If the moisture rating is below 3 pounds per 1000 square feet, your concrete subfloor is dry enough to sustain an epoxy floor finish. If your floor surface has a rating slightly above 3 pounds of moisture per 1000 square feet, apply a penetrating sealer that will close the pores of the concrete, and render it drier and more stable to support the epoxy floor finish.

Step 2: Clean the Concrete Surface of All Foreign Material

Sweep the concrete floor with the stiff broom to get as much dust, sand and other dirt off. Wash the floor with a degreaser. If oil stains remain, sprinkle lime powder over them and let it sit overnight. Vacuum this material up in the morning with the shop vacuum.

Step 3: Etch the Floor Surface

Epoxy flooring compound will not adhere properly to a surface that is too smooth. Mix the etching compound according to the directions provided, usually half and half etching compound and water. Apply the etching agent to the floor in wide sections with a stiff broom, going left to right, then up and down over the section to ensure all areas of the floor are exposed to the etching agent. Rinse off the etching agent with warm, then cool water. Vacuum up any damp spots with the shop vacuum.

Step 4: Prepare to Apply Concrete Primer

Sweep the floor once again and then vacuum it with a household vacuum cleaner. Use the low-nap roller applicator to put concrete primer in a thin, even coat all over the concrete floor. Allow the primer to dry for about 30 minutes before mixing the epoxy to apply it.

Ensure your concrete subfloor is clean, dry and suitably roughened with etching and primer to be able to form a superior bond with the epoxy flooring before you apply the epoxy, for the most satisfactory results.