You’ve put in a lot of time and effort into polishing a concrete floor, adding the concrete densifier, grinding multiple times, then going over the surface another several times with polishing pads to reach that ideal shine. Now, you want it to last as long as possible and maintain it’s attractive appearance.

The last question is, should you add a coat of grout to fill any pin holes, cracks, or flaws in the surface before considering the task complete? The short answer is, “Not necessarily.” Contrary to popular belief, grout coats don’t need to be added to every polished concrete floor. Let’s dig a little deeper into what grout does, why you would add it, and when it may not be needed.

Why Grout a Concrete Floor?

Concrete is a naturally porous material, and while densifiers help with increasing the crystalline bonds and make the substrate more durable, there can still be pin holes and small voids that form in the surface after grinding and polishing. Not only do the pin holes minimize the clarity and shine of the polish, they can lead to more serious cracks and gouges over time, reducing the lifespan of the concrete.

Grouting the floor allows you to fill in those holes and flaws in the surface, extending the life of your slab and helping to maintain the highly glossy appearance. While holes and voids less than 2 mm can be fixed with a grout coat, any cracks or crevices larger should be treated with a concrete patching compound.

Why Not Use Grout On a Polished Floor?

When the slab you polished has a good density and the aggregate is regular and even, there is minimal porosity. The crystalline structure is solid and should withstand traffic and other elements easily. Adding a grout coat after polishing would be redundant and unnecessary.

Testing Grout in a Mock-Up

We always stress the important of doing a mockup to know how the concrete will perform, be aware of any issues, and also, you’ll know whether the slab will benefit from a grout coat. Get the testing area to the gloss level you want, then grout one side and leave the other bare. You’ll be able to see if the grout coat was beneficial to the final result or didn’t make a difference.

Contact Us for Epoxy Grout for Concrete Floors

While some contractors will use concrete dust to create a quick, free grout, the amount of paint chips, debris, and other foreign matter will compromise the quality of the grout. We recommend either marble flour because it’s contaminant free or an epoxy grout that flows smoothly and is easy to trowel into place. To learn more, reach out to our sales team today for grout, grout pans, and other concrete polishing equipment at 815-472-9754 or fill out our contact form.