Decorative Concrete - Internal Stains
About Acid Stain
Acid Stained floors are growing in popularity. Many people are looking to stained floors as an alternative to carpet, tile and wood.
Acid Stains are not a paint, a coating or a sealer. Acid Stained Concrete is a colouring process involving a chemical reaction on a cementitious material. A solution made with water, acid and inorganic salts reacts with minerals already present in the concrete.
How Do Acid Stains Work?
All concrete has calcium hydroxide as a biproduct. This is slaked lime. This picks up carbon dioxide from the air and becomes calcium bicarbonate. This is effluorescence. These are the chemicals that the stain reacts with.
Acid stains are made from hydrochloric acid, wetting agents and metallic ions. When this solution is placed on concrete, it colours the concrete by chemically combining the metallic ions with the particles in the concrete to form oxides. The result of this reaction is colour.
Chemical stains can be applied to new or old, plain or coloured concrete surfaces. Although they are often called 'acid stain', acid is not the ingredient that colours the concrete. Metallic salts in an acidic, water-based solution react with hydrated lime (calcium hydroxide) in hardened concrete to yield insoluble, coloured compounds that become a permanent part of the concrete.
Selecting the Right Stain
There are many manufacturers of Acid Stain. Most produce stains in 8 colours that are variations of three basic colour groups: black, brown, and blue-green.
For more photos, visit our Gallery.