Because of concrete’s porous qualities and neutral tone, it is the perfect blank canvas for applying color. Using acid-based chemical stains, decorative concrete contractors have been able to achieve rich, earth-toned color schemes resembling natural stone, marble, wood, or even leather, giving a completely custom look to cement floors, concrete driveways, patios, walkways, pool decks, concrete walls and more.
Most acid stains are a mixture of water, hydrochloric acid, and acid-soluble metallic salts. They work by penetrating the surface and reacting chemically with the hydrated lime (calcium hydroxide) in the concrete. The acid in the stain lightly etches the surface, allowing the metallic salts to penetrate more easily. Once the stain reacts, it becomes a permanent part of the concrete and won’t fade, chip off, or peel away. Like stains for wood, acid-based stains are translucent and the color they produce will vary depending on the color and condition of the substrate they are applied to. Each concrete slab will accept the stain in varying degrees of intensity, creating natural color variations that bring character and distinction to each project. What acid stains don’t offer is a broad color selection. You’ll mostly find them in a limited array of subtle earth tones, such as tans, browns, terra cottas, and soft blue-greens. But newer products on the market such as water-based penetrating stains and water- and solvent-based dyes are greatly expanding the color choices available. These colores can range from soft pastels to vivid reds, oranges, yellows, and purples.