Buying Acid-Based Concrete Stains

If you want to achieve natural color variations that give your concrete floor or slab character and distinction, then an acid-based chemical stain is your best choice. Like stains for wood, acid-based stains are translucent and the color they produce will vary depending on the color and condition of the concrete surface they are applied to. Each concrete slab will accept the stain differently, giving you varying degrees of color intensity. What acid stains don't offer, when compared with water-based stains, 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. (See these color charts.)

Here are some additional buying tips:

Conduct a color test. Before buying an acid stain, be aware that some colors can be deceiving in liquid form. For example, a stain may look green in its container but will take on its actual color after it has reacted with the concrete surface, ultimately turning into a medium or dark brown. Always test the stain in an inconspicuous area on the surface to be treated to ensure the color and aesthetics are exactly what you're aiming for. Some manufacturers sell small sample sizes of their products or test kits with samples of every color in their line.

Buy the right amount. Once you are confidant that the stain is the right color, then calculate how many gallons of stain you'll need for your project. Measure the square footage of the concrete surface, and then check the recommended coverage rate for the product you plan to purchase. Most stains provide a coverage rate of 250 to 300 square feet per gallon.

Get the appropriate application tools. Because most chemical stains contain hydrochloric acid, you'll also need to buy acid-resistant tools to apply them. (See Basic Tools for Applying Stains.)