For a polished concrete surface that looks good today and maintains it’s sheen and smooth surface over time, it’s necessary to add a layer of grout. We’re walking you through how to grout concrete floors, why it’s important, and what not to do. Want to see the process in action? Check out the video below.

What Does Grouting a Concrete Surface Do?

When you grind a concrete surface, you’re opening the slab and the small cuts and scratches leave pinholes and micro pits in the surface. They may not seem like a big deal at first, but, if left untreated or unfilled, and you polish the floor or apply a floor coating over them, you’re compromising the durability of the slab. Dirt and sediment on shoes will grind into those micro pits and pinholes and continually cut into them, making them larger over time while air trapped in the pits under a coating will expand and press upwards, preventing proper adhesion.

Adding a layer of grout during the process fills in those voids and gaps and seals them. From here you can continue using a finer grit pad to begin the polishing process or add a coating.

How to Apply Grout to a Concrete Surface

After using a coarse to medium-grit diamond on the slab, you’ll want to eliminate all the excess concrete dust or slurry to ensure a smooth, clean surface free from contaminants. Then, you’ll want to apply your 100 percent solids epoxy to the concrete slab in a skim coat, making sure to work it over the pinholes and micro pits in the slab.

Once the skim coat of epoxy has been applied and is still wet, sprinkle a heavy coating of marble flour on the surface. Attach grout pans to your floor grinder or use grout pans manually in a small area as these will combine the epoxy and marble flour while pressing it deeply into the void, filling the holes and eliminating any air pockets. Leave it to cure for six hours before moving on to the next step.

Marble Flour or Concrete Dust

We are often asked if you can use the concrete dust from grinding to grout the floors rather than marble flour. The problem with this is that the concrete dust is contaminated with dirt, large chunks of concrete, and other materials, so it won’t form the proper bond into the holes and pits. Marble flour has the benefit of even particle sizes and quality control to ensure there aren’t contaminants that could affect the project negatively.

Contact Us for Concrete Grinding Equipment and Supplies

From grout pans to concrete grinders, we have everything you need to complete your surface preparation project. Reach out to a member of our customer service team today at   (815)472-7944 or fill out our contact form!