Staining decorative concrete is not only aesthetically pleasing but it can also be environmentally friendly. Although there is no one-size-fits-all stain for every decorative concrete job, water-based stains are a great option for contractors looking to make their decorative work a little more green. Water-based stains do not contain the solvents that acid-based stains do. This allows contractors multiple benefits.
Low VOC content. Low volatile organic compounds (VOC) content creates a healthier environment. Contractors will not be breathing in the VOCs. Water-based stains also do not have the acid-related smell. This also allows contractors to do work with water-based stains in indoor or outdoor environments where other people are present during completion of the work. Depending on the formulation for the water-based stains, they can also be acceptable for use in LEED projects, says Cam Villar, director of marketing for L. M. Scofield.
Cleanup. Acid-based stains require neutralizing and cleanup prior to sealing the concrete. The residue and water from acid stain cleanup needs to be handled and disposed of properly. Water-based stains do not require the stringent residue removal procedures that acid-based stains do, Villar adds. In fact, water-based stains do not require the floor be washed off after application, says Jim Nielsen, regional sales/training manager for Butterfield Color. Nielsen says contractors doing vertical wall stamping tend to gravitate toward water-based stains because they do not require the wash down and cleanup like acid stains. Plus, once a water-based stain has cured properly it may be sealed.
Color selection. “Because of the metallic salts used in the manufacturing of acid-based stains, only so many colors are available,” Nielsen says. Water-based stains can have a bigger color selection beyond the earthy tones common for acid stains. “Water-based stains are available in brighter and more primary colors,” he says.
Longer evaporation point. Water-based stains evaporate at a slower rate than acid-based stains. This allows the stain to stay on the concrete longer and give the color a longer time to sink into the concrete, says Alex Darmstaedter, marketing manager for American Decorative Concrete.
All the benefits of water-based stains don’t necessarily mean they are hands down better than acid-based stains. There are some aspects of water-based stains that might not make them the stain of choice for certain projects.
UV susceptibility. “Water-based stains are generally not as long lasting as acid stains since the organic pigments used in water-based stains are more susceptible to UV light,” Villar says. Using a sealer that contains UV blockers can help diminish this issue somewhat, he adds. Some water-based stains are now formulated with UV stabilizers in the stain as well to help prevent fading in sunlight, whether the stain is used indoors or outdoors, Darmstaedter adds.
Color intensity. Although there are more color options with water-based stains, these stains have to penetrate into the concrete whereas acid stains react with the surface of the concrete, Nielsen points out. In addition, neither type of stain is intended to cover or hide construction defects; however, the stain applicator can sometimes control the amount of variegation or mottling to artistically incorporate the defect into the final look, he adds.
Surface prep. Because the stain needs to penetrate into the concrete, surface prep is a very important step when applying water-based stains. “You need to ensure proper floor prep and cleaning so that the stain can penetrate into the surface,” Nielsen says. The concrete also needs to be dry. If there is still moisture in the concrete it may be difficult for the stain to absorb, and it will not take.
Stenciling. If a project calls for stenciling, water-based stains might not be the best option. “Water-based stains or dyes can tend to seep under a stencil and form uneven edges,” Darmstaedter says.