This 8,000 square foot remodel for a store in Irving, TX is a prime example of how economical and yet striking acid stain for concrete can be. It was a nice sized decorative concrete project that took us a couple of days just to clean and prep the floor. Next, we applied a Kona brown acid stain to the concrete that created a rich patina, which varies in color throughout the floor; even the cracks in the floor add to the beauty. The owners loved both the color and the price. Acid stain for concrete is a low maintenance, economical alternative to other types of flooring.
In some of the pictures you can see differences in the color of different parts of the floor. Why? Acid stain for concrete floors is a reactive process; when the stain hits the concrete floor, it reacts with its minerals, changing the color in a non uniform way; that's why it looks so beautiful. A good part of this non-uniform change is driven by the texture of the floor. This store's concrete floors have two types of texture—hard trowelled (smooth) and broom finished (rough).
Normally all interior concrete floors will be hard trowelled while exterior patios and sidewalks will have a light broom finish. Builders create hard trowelled floors by using a "whirly bird" machine which is basically a large upside down fan with steel blades that spin over the surface of the concrete as it is hardening, burnishing it. This smooths out the concrete. In darker areas in the floor, the concrete is denser (less porous), and in lighter areas, it's more porous. Exterior concrete is usually finished using a broom lightly dragged over the hardening surface, creating shallow grooves and a fairly uniform finish. You can see the difference in the pictures of the store's entrance. When the acid stain for concrete was sprayed on the hard trowelled part of the floor, the different floor densities created rich color variations because the acid stain couldn't penetrate evenly. In the broom finished floor closer to the entrance, because it has a more even finish, the acid stain does not have as much variegation. Check out our next decorative concrete project where we share some insights on how to prepare to acid stain large driveways.