Since 1991, The Face Companies has been recognizing the flattest and most level concrete floors with its Golden Trowel awards. The company named seven Gold Plate and four Silver Plate winners in the 2012 competition, three of them world records. Entries from three countries — the United States, Canada and Australia — were among this year’s acknowledged contractors.
Floor levelness and flatness measurements used to determine winners in the competition are based on the F-Number system, first introduced to the concrete industry by The Face Companies in 1982 and adopted by the American Concrete Institute (ACI) in 1990 (ACI 117). Following are descriptions of two winning projects. See the sidebar on Page 32 for all the 2012 Gold Plate winners.
Emmi Roth Cheese Factory
Smykal Construction took home a 2012 Golden Trowel Award for its floor at the Emmi Roth cheese factory in Platteville, Wis. It was Smykal Construction’s first superflat placement, narrowly missing a world record in the Narrow Strip category with its FF 171/FL 95 on the 19,500 square foot job. Smykal Construction enlisted the help of consultant Eric Palmquist of Precision Concrete Floors, LLC, in Oshkosh, Wis., for the superflat portion of project.
Emmi Roth is an international cheese and dairy products company. Smykal Construction had the full concrete package at the new cheese factory, supplying an 80,000-square-foot foundation for the steel building along with thick foundation bases and walls for the milk silos. The cheese factory required a superflat floor in the room where the cheese ages. That’s because the aging process is aided by a robot that runs up and down the narrow aisles picking up cheese wheels, flipping them and returning them to the rack.
The 9-inch-thick superflat floor in the climate-controlled room included #5 rebar placed 1 foot on center. The slab sat on a 3-inch mud slab with 4 inches of foam and a 45-mil vapor barrier. The placement was done in 16-foot-wide strips, 130 feet long.
Shane Smykal, VP and partner at Smykal Construction, explains the superflat process demands more precision and time than your typical flatwork placement. “Formwork is the key to getting high FL numbers,” he says. “The formwork has to be dead on.”
Smykal adds that achieving high FF numbers is all in your placing and finishing technique, which requires a lot of handwork. The finishing crew on the Emmi Roth project truss screeded, hand struck with a saw beam, bump cut, panned with riders, then hard steel troweled the floor. “Everyone on your finishing team has one or two jobs to focus on, and if one person isn’t doing his job properly it can throw things off,” Smykal adds. “It is critical that everyone works together as a team.”
Smykal also credits his ready mix supplier, Bard Material. “They did an outstanding job with service and consistency, which is crucial in any slab placement,” he says.
Adding to the challenge of the project, the floor was designed jointless to reduce the chance of curling. The engineer specified a wet cure to reduce the chance of cracking. Smykal says despite his skepticism, there isn’t a crack anywhere on the floor.
Rigby’s Family Entertainment Complex
The roller skating rink floors at Rigby’s Family Entertainment Complex in Warner Robbins, Ga., garnered one of the two world records Birdwell & Associates and Skene Concrete collected in the 2012 Golden Trowel Awards. Bryan Birdwell of Birdwell & Associates says everything aligned for this project to result in a world record, including the owner essentially turning the job design over to his company, allowing them to plan the mix design, subgrade prep, and concrete place and finish.
Birdwell & Associates utilized its proprietary floor system, F.A.S.T. Floor, on this project. F.A.S.T Floor is a jointless, shrinkage- and curl-compensating concrete slab design that uses high doses of macro fiber as the reinforcing agent. Birdwell says the Rigby floor has no curling, and Dipstick measurements taken periodically in the floor’s first year show elevations consistent with the original placement.