A STONE CANVAS

ubtle earth tones like tans, terra cotta, browns, and blueish-greens are transforming the perception of finished concrete from the rough sidewalks and garage floors many have always known to gorgeous, unique floors, countertops, fireplaces, sinks, and other architectural designs where decorative stonework is often utilized. Acid-etching techniques make this transition possible. The otherwise drab perception of concrete takes on individualized character with the choice of color and method of application. Each project results in a unique work of art. Even the most complicated designs, once assumed the sole realm of mosaic tile or multiple cuts of stone, are now easily and beautifully realized with acid-etching techniques. Curves and unusual design elements are equally within reach.

Stenciling, cutting, and sandblasting can all create dramatic effects both before and after staining is applied, further personalizing your project. Compared to similar effects created with ceramic tiles or multi-stone installations, concrete is much easier to clean and maintain.

BEAUTY AND LONGEVITY

In 1927, The Ahwahnee Hotel at Yosemite National Park was host to the first significant acid-etched staining project of note. Architect Gilbert Stanley Underwood instructed his contractor to mix and apply certain chemicals with water on concrete floors of the hotel. Workers etched patterns into the floor surfaces and then used the mixture to produce different colors. The Ahwahnee is the best evidence today that stained concrete floors are durable. Though the floors have been subject to over 75 years of foot traffic and other abrasive wear and tear, the colors are still as vibrant and evident as they were at installation.

HOW IT WORKS

By nature, concrete’s neutral tone and porous qualities make it a perfect canvas for staining. 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 gently etches the surface, allowing the metallic salts to penetrate more easily. Once the stain reacts, it becomes a permanent part of the concrete and will not fade, chip off, or peel away. Like stains for wood, acid-based stains are translucent and the color they produce will vary depending on what they are applied to. This technique can be used indoors or outdoors, on projects new or old. The unique characteristics of the original concrete mixture, additives utilized, finishing methods employed, age of finished concrete, and moisture content as the staining is applied will all factor in to the resulting colorization. Outdoor acid-etching results continue to change long after the process is complete due to exposure to sun and moisture.