huge potential for a brand-new industry

findarticles.com Author: Joe Nasvik

Imagine a concrete floor as shiny as glass–this is a look that diamond polishing can achieve. Two years ago very few people in the United States had even heard of polished concrete other than terrazzo floors. Terrazzo floors use carborundum stones to grind and polish floors to a 120- to 150-grit finish (grit refers to the micron particle size of the diamonds or other grinding abrasive material). Diamond-polishing technology now makes it possible to grind and polish much faster on concrete surfaces at up to 3000-grit finishes.

Today, most decorative concrete contractors are aware of the creative possibilities that polishing techniques can add to their finishes. But the reasons for polishing concrete go far beyond decorative. Warehouse owners, for example, are willing to pay for diamond polishing of their floors in order to reduce maintenance costs and solve problems involving sealers or water vapor transmission. John Abrahamson, National Sales Manager for Vic International, Knoxville, Tenn., notes that an added benefit for warehouse applications is that forklift tire marks don’t adhere to the surface.

But the new technology for polishing concrete comes from the stone-polishing industry, not the terrazzo industry. According to Abrahamson, it has been available for 4 years in the United States with significant improvements in the past year–especially in dry, dust-free grinding. Although there have been polished concrete floors in Europe for about 8 years, advertised as “superfloors,” developments in diamond technology are the result of U.S. efforts.

Advantages of polishing

Saving money on maintenance, solving existing concrete problems, providing commercial floors that don’t show traffic wear (store aisles, for example), and providing new, artistic decorative concrete surfaces are the most common advantages of polished concrete.

Polished concrete floors are essentially no-maintenance surfaces. Owners of commercial and warehouse floors typically find it expensive to maintain their floors with sealers and waxes. And if a floor surface is sealed so that water vapor can’t get through, there can be additional problems down the road. Removing all previous treatments and then polishing the floor can be a one-time fix that saves money. After diamond polishing, the only maintenance required is removing dirt, oils, and other materials that could stain. Even chewing gum won’t stick to a polished floor, according to Bill Kulibert, president of American Polished Concrete, Shreveport, La., a company that specializes in warehouse flooring and large commercial projects.

Diamond-polished floors also have good water vapor transmission. Some of Kulibert’s work has come from others’ failures, for example removing epoxy sealers that have caused trapped water problems or that haven’t bonded properly.

Decorative effects

There are two ways to polish concrete:

• Polish only the cement paste and fine aggregate brought to the surface of the concrete during final troweling.
• Grind and polish into the matrix of a slab to expose large aggregates.

To further enhance the look, special aggregates like broken glass, seashells, bits of plastic, or pieces of metal–and anything else creative minds can imagine–can be seeded into the surface of freshly placed concrete.

Doug Demmert, Demmert & Associates, Glendale, Calif., was recently asked to grind a poorly done 3500-square-foot colored residential floor. Removing the sealer and polishing the floor solved the problem and provided a new decorative effect.

Decorative concrete contractors like polished concrete because of the range of artistic possibilities that can be achieved. Demmert, whose work is mostly interior residential, often grinds floors deeply enough to reveal the aggregate, resulting in a look that many customers find appealing. Recently, he chemically stained a floor when the grinding process was half complete. “The resulting finish and color look more natural than typical chemical staining,” he states.

Lance Boyer, Trademark Concrete, Los Angeles, who subcontracts polishing, recently completed a project with Type III cement, which he says provides a softer color. He seeded aggregate onto the surface and floated in zinc strips, then exposed them by grinding and polishing. His company also recently polished an integrally colored slab, adding chemical stain highlights just before final polishing.

Scott Thome, a sales representative in Minnesota for Los Angeles-based L.M. Scofield, is aggressively pursuing the polished, colored overlay market. Taking a lesson from the terrazzo industry, he will set zinc strips on a large upcoming project to form complicated patterns and will place several colors of overlay cement between the strips. The overlay will be 3/8 inch thick, making it economical to use the more expensive green and blue concrete colors. Because there are no large aggregates, the polished appearance is more even and controllable. The architect on this job, Sam Sisic, Antunovich and Associates, Chicago, said that this installation will have very heavy foot traffic and acknowledges that the owner is taking a chance using a new product like polished concrete, but he is confident that the results will justify the decision.