Grinding vs Acid Etching Concrete Before Epoxy
Coatings bond to a rough surface. Smooth concrete lets go. Before any epoxy floor, the slab has to be ground or acid-etched until it feels like 120-grit sandpaper.
Grinding concrete
A floor grinder with a diamond wheel cuts the top layer off the slab. It works on any concrete, including floors that were sealed, painted or coated before. Most tool rental centers rent a floor grinder by the day. Rent one with a vacuum attachment to control the dust.
Acid etching concrete
An etching solution opens the surface of bare concrete. It costs less than renting a grinder and needs no machine. It does not work on concrete that is sealed, painted or coated, because the acid cannot reach the slab. After etching, rinse the floor well and let it dry fully before you coat.
Which one to use
| Your floor | Use |
|---|---|
| Bare concrete that soaks up a few drops of water | Grinding or acid etching |
| Sealed concrete, where water beads on the surface | Grinding |
| Painted or coated before | Grinding |
| Very smooth, troweled concrete | Grinding |
How to tell when the concrete is ready
Run your hand over it. The whole floor should feel like 120-grit sandpaper, with no smooth or shiny patches. Vacuum all the dust before you coat.
Next steps
Not sure which your floor needs? Call (877) 703-7699. If we miss you, we call back within an hour.
