Like many concrete floor contractors, we were just plain scared of the "F" word: F-number specifications for concrete floors. Even though we'd been a concrete contractor in California since 1906, there had not been any floor projects in our area requiring F-number flatness. The Nestle distribution center, the first project in our area to include floor flatness specifications using F-numbers, is a tilt-up concrete building with a floor area of 700,000 square feet.
On the Nestle project, the "pan method" of floating and rearranging the concrete surface during its plastic state immediately became a great labor-saving tool. It eliminated most of the highway straightedging and reduced the number of finishers we needed for the job. The pan performs the same function as the straightedge or any other tool used in the floating operation. It moves the top 1/4 inch of concrete, cutting bumps and filling dips in the surface. Each pass of the pans further refines the flatness of the floor until the concrete surface hardens and can no longer be moved.