Make Your Exterior Concrete Sealer Stick

Cleaning methods

Regardless of whether contractors stamp with powdered release or use tinted liquid, they must be sure to thoroughly clean the slab of excess release before sealing. This can be done either with a pressure washer, a highly diluted muriatic acid wash, or soap and water with a very stiff scrub brush. Some contractors have even reported using rotary floor scrubbers to clean the slab. Simply using a soft push broom and a garden hose will not remove nearly enough residue.

Removing release with only a garden hose and broom will leave a fine film of release over the entire slab, high spots and low. When this film is sealed over, the overall job will more closely resemble the antiquing color than the base color and will be more prone to peeling. To minimize sealer problems and give a good two-tone appearance, the release color should be evident only in the joints and depressions, and the high spots should exhibit only the base color.

I prefer to stamp with powdered release and then use the acid wash method to remove excess release. Even a high-powered pressure washer is usually not enough to completely remove the haze of release, and the bulky pressure washer is cumbersome to haul around. When I put away my 4000-psi pressure washer and began using the acid wash method, the quality of my work improved. It began to look more like the glamour shots in magazines. In addition, my sealer issues were dramatically reduced, including the tendency for the sealed surface to be slippery when wet.

Acid washing allowed me to remove all of the release that wasn’t actually embedded in the paste. My work then exhibited the two distinct colors that the customer had picked from the color chart, instead of a muddy-looking mixture of the two. In the rare event that I did need to touch up the sealer, a simple clear coat without antiquing brought the slab back to its original appearance — even when resealing neglected slabs years later.

Because stamping with liquid release is so much cleaner and easier, some contractors never use powdered release. For them, a water-based cementitious antiquing agent is now available that’s applied to damp concrete surfaces. It puddles and creates two-tone effects like tinted liquid release, but because it contains cement instead of bond breakers, it adheres tenaciously to the surface even if the sealer deteriorates. Two such products are Perma-Tique from Butterfield Color and EZ-Tique from Proline. There are others, of course, but these are the two I have used personally. Not only are they great for antiquing new stamped concrete, but they can be used to restore antiqued highlights to aged concrete as well.

Steve VandeWater manages The Concrete Store in Fishers, Ind. He is a former Indianapolis-area contractor and is founder of the Indiana Decorative Concrete Network website. E-mail [email protected]; visit www.indecorativeconcrete.com.