In My Experience - Concrete Finishing: To Grind Or Not To Grind
14 July, 2020
Concrete can be prepped mechanically (grinding) or chemically (acid etching). My company uses grinding every time as the surface prep method for concrete, even when it is new concrete. It is very physical work, but it gives you the peace of mind of knowing that your coating will not fail, because when you grind, you are creating a profile on the surface for your coating to adhere to. I have always felt acid etching does not provide the same level of certainty, because you don’t know for sure if you have etched enough.
We use Milwaukee grinders with Diamabrush attachments and hook them up to Festool dust extractors. The process is chemical-free, and the dust is well contained. When grinding is complete, we do a final vacuum, and we are ready to apply epoxy coatings or decorative stains, whatever the finish may be. If there are any cracks or cosmetic defects in the concrete, we fix them prior to grinding so that the repair won’t be visible when finished.
It also saves time. In prepping concrete mechanically with grinding instead of chemically with etching, there will be less downtime and quicker turnaround in returning floors to service. With chemicals, on the other hand, after you etch, you would have to rinse heavily with water and then wait a day or two for it to dry before finishing.
Garage floors are a common application for grinding and applying epoxy coatings. The biggest risk upon completion is that hot tires will drive onto the floor and pick up the finish. This is the most common cause of floor coating failure in garages. With grinding as your prep method and proper application of good products, that risk is minimized greatly.
By Alex Carlos Estrada - Color Unlimited Painting, Mesquite, TX