Acid staining is not paint or a coating agent; rather it is a coloring process. This process involves a chemical reaction on cementitous material. A solution made with water, acid and inorganic salts, reacts with minerals already present in the concrete, resulting in exquisite color. It works very well on new or old concrete, and we have seen impressive results over decorative polymer overlays as well as self-leveling products. Acid stain is a very durable product if properly protected with sealer or wax and may be applied to both interiors and exteriors.