How to Paint a Concrete Floor With Epoxy?

Posted by Pedram Mojarrad on

Epoxy flooring is a durable solution for concrete. Not only does it prevent concrete from ingress of aggressive ions, but also gives the concrete floor a much better look. But it can be a bit tricky. Have a look at our checklist as follows:  


Check For Moisture

Check for existing moisture issues. If your slab was originally poured with no underlying vapor barrier or you have high ground water, it’s possible for water vapor pressure to actually lift coatings off the surface. Tape a 50 x 50 cm piece of clear plastic over the slab and leave for 24 hours. If you see the concrete darken or water droplets form, consult an epoxy supplier for solutions including surface applied vapor barriers.

Assemble Tools + Materials

You'll need a 2-part epoxy kit (like GreatFloor-100, 200 or 300) with concrete etch, degreaser, floor patch, floor scraper and squeegee.

Give It a Good Sweeping

Use a broom to clean the slab. Be sure to get up against walls and around garage door tracks.


Scrape + Degrease

Scrape up any hard dirt or grease. For stubborn areas, apply full concentration degreaser and then continuously scrape the surface. 


Wash + Squeegee

Once the heavy stains are up, quickly wash the entire floor with diluted degreaser.

Quickly remove the standing liquid with a foam squeegee. The goal is to not over wet the floor so it will also dry quickly.

Apply Etch Pretreatment

Mix the citric acid concrete etch with warm water per the instructions. Then apply, scrub, and squeegee off the floor in the same manner as the degreaser. The citric acid will help open the top pores of the concrete so the epoxy adheres well.

Let It Dry

Use fans as necessary to completely dry the floor overnight. Allow longer dry times in cooler temperatures.

Test For Existing Sealer

Check to see if there is still top sealer on the floor. Drip water onto the slab. If the water beads up, there is an existing sealer that may interfere with the adhesion of the epoxy. Depending on how much sealer is left, you may have to repeat the etching process. 

Patch Cracks

Take time to fill concrete cracks and voids as these imperfections will show through the epoxy. You can use Multi-Filla or Concrete Epoxy LV, or even Concrete Repair Epoxy Mortar.

Mix (1) part A to (2) parts B on a clean piece of cardboard and then fill cracks and voids using a plastic scraper or spatula.

Allow the filler to harden for eight hours and then feather down any edges with a coarse sanding block.

One Last Cleaning

Give the space one more good cleaning before applying the epoxy. Be sure to get close to edges and walls for bits of block and concrete that will get into the finish.

To make cutting in easier, apply painter’s tape along any block and wall plates (basically anything you don't want the epoxy on).

Mix Part A With Part B

Your epoxy kit should have come with a large and small can. The large can of Part B may feel light but it is only partially full so that you can pour Part A into it. Epoxy is available in various colors but the most popular is grey.

Pour Part A into Part B. Then mix thoroughly until the liquid is homogeneous.


Cut In

Pour the mixed epoxy into a roller tray and use a normal brush to cut in along edges. 

Roll in Sections

Start rolling the epoxy out in 1 x 1 m sections. Keeping the wet edge. Also be sure to plan your exit strategy as the floor will need to dry for 24 hours before light traffic. You don't want to paint yourself into a proverbial corner!

Apply Gengerously

In general, roll out the epoxy heavier than you think is needed. The epoxy gets absorbed into the concrete pores and will lose its gloss if it is not applied heavy enough. 

Let Cure

Finishing an existing garage floor with a new epoxy coating is a great way to refresh your DIY workspace while also making the floor much easier to keep clean in the long run. Be sure to allow the proper times for light foot and vehicle traffic (1 and 3 days respectively).

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