Polishing Dry-Shake Color Hardener: Yes or No?
By Christina Camara

Concrete Decor asked two experienced contractors to discuss the special considerations involved in polishing floors after using dry-shake color hardeners to color and harden the surface. Their views: One prefers to avoid dry-shake color hardeners altogether when installing polished surfaces, while the other says polishing can be done successfully if contractors are aware of a few potential problems.

Polished concrete floors, with their gleaming surfaces and low maintenance requirements, are popular choices for car dealerships, big box stores and malls, as well as private homes. Options for coloring them include dyes that are specifically designed for polished concrete, an integral color that is added to the mix before pouring, acid stains, or shake-on color hardeners that are tossed by hand onto fresh concrete and worked into the surface with a float or trowel.

The method of hand-broadcasting dry-shake color hardeners, which results in inconsistent thickness, is one reason why Jeff McCool avoids them if he’s going for a polished look. Because polishing means grinding the surface to achieve the desired smoothness and shine, there’s a risk of removing the color altogether if the dry-shake is applied too thinly, he says.

“I tried that on one job and it did just what I said it would,” says McCool, of Jeffco Concrete Contractors in Tuscaloosa, Ala. After one pass with the diamond polisher, he says, “it looked like a spotted dog out there. We kind of learned that is not the way to go.”