November 3, 2023
Concrete acid stain is a great way to add color to new and old concrete floors. It's not a paint or a coating, it's a process involving a chemical reaction between the acid stain and the cementitious materials in the concrete. Acid stained concrete will give you a mottled, marble like, variegated look. If you're looking for an even, solid color then concrete epoxy floor paint will give you that look.
Acid stained concrete floor in finished basement
The color variations of acid stains from slab to slab will be different. You may even have different color patterns on the same concrete floor.
These variations in color and mottling are what make acid staining concrete so unique and special.
How it works:
Acid stains are made from hydrochloric acid, wetting agents and metallic ions. When this solution is placed on the concrete it colors the concrete by chemically combining the metallic ions with particles in the concrete to form oxides. The result of this reaction is color.
Now the acid is not the ingredient that colors the concrete. It's the metallic salts in an acidic, water based solution that react with hydrated lime in hardened concrete to produce insoluble, colored compounds that become a permanent part of the concrete.
There are many different manufactures of acid stains and most produce these basic colors:
In general, cements that produce larger amounts of calcium hydroxide during hydration will show more stain color, and higher cement contents produce more intense colors.
If they are near the surface, calcium-based aggregates, such as lime-stone, take stain readily and deepen the color of the concrete above them. Solid aggregates, such as gravel, don't react with the stain.
Acid stains can be applied to older existing concrete floors if they are in good shape. If the surface is worn or deteriorated click on MICROTOPPINGS AND SKIM COATS to see how they can provide a new steel troweled surface that can be stained.
Click on HOW TO STAIN CONCRETE preparing the surface for the stain. This is very important.
Click on HOW TO STAIN CONCRETE FLOORS for a step by step guide on how to stain your concrete floor.
Click on BEHR CONCRETE STAIN to learn about this type of non-acid stain.