In the decade since he began offering polishable overlays using TRU® Self-Leveling architectural topping, contractor Matt Konchan’s perfected the art of quickly delivering beautiful and durable floors for less than half the cost and installation time of terrazzo.
That’s what he did as subcontractor to long-time partner MH Williams Construction Group, which was the general contractor on a new, 35-acre facility for Mike Erdman Auto Group in Cocoa, FL. For the dealership’s 4,300-sq-ft showroom floor, the project owner initially wanted to polish the newly placed concrete slab. Instead, MW Williams called in Konchan Polishing Inc. of Inverness, FL, to explain how a polishable overlay could be customized to look like terrazzo — but for less than half the price.
Konchan recommended a two-to-one mix of TRU® Self-Leveling Gray seeded with equal amounts of size 0, 1 and 2 aggregate in China White and Canadian Black followed by a 10% broadcast of silver-coated glass.
Such mixes are referred to as TRU®azzo. This particular mix sets off the dealership’s 8-foot, red-and-black, custom-stenciled logo, which Konchan also installed.
“With overlays, we have a lot more control over the outcome,” says Konchan, who started in the concrete polishing industry after high school. “The inspiration was a terrazzo look, and we were able to give all sorts of custom options to provide this appearance.”
Because the substrate was newly placed concrete, Konchan didn’t have to use an underlayment like LevelFlor® to fill in gouges or other wear and tear that inevitably damages substrate over time. Instead, his crew ground the substrate to CSP 2 and then brought it to CSP 4 by applying TXP™ Fast Epoxy Primer with coarse sand to rejection. This preparation process optimizes the overlay’s adhesion to the substrate.
The crew placed all 4,300 square feet in one pour without interruption, starting at 1 pm and ending by 4 pm. Once the two-to-one mix of TRU® with black-and-white aggregate was placed in a section, the crew manually broadcast silver-coated glass over roughly 10% of the area. The crew finished each section by going over the just-installed floor with CTS Cement Manufacturing’s TRU® Self-Leveling Spiked Roller. The roller reduces pinholes by releasing trapped air. Generally, one pass down and back is all that’s needed.
Ultimately, the crew used approximately 260 50-pound bags of TRU and 130 bags of aggregate. Because TRU allows for grinding wet or dry and polishing in 24 hours, the crew was able to polish the overlay the next day.
Bringing Out the Beauty
The crew exposed the aggregate using 20-, 40- and 80-grit metal bond discs on a grinder. They transitioned to 100-, 200-, and 400-grit ceramic discs; and finished with 800- and 1500-grit resin heads. At 100 grit, the crew pit-grouted floor to fill in any surface inconsistencies. They waited about 90 minutes and then continued grinding.
An application of penetrating sealant followed by a high-speed burnish brought the floor to a high-gloss finish that’s meeting the client’s requirement for beauty and durability.
“When you polish concrete, you’re at the mercy of what’s existing or what the contractor placed,” Konchan says. “I love overlays because I have complete control over the final product, and without the typical aesthetic weaknesses of a concrete slab.”
