Q. I work for a heavy-equipment dealer and we have some pitted concrete in our repair shops. Do you have any thoughts on repairing the pits and cracks that would stand up to the rigors of tracked equipment being driven over the surface on a daily basis? We are looking at several types of epoxy sealers.
A. The best recommendation we’ve seen for such a floor comes from the Naval Facilities Engineering Service Center. For a floor that will tolerate moisture, impacts, and chemicals (such as an aircraft maintenance shop) for up to 10 years, it recommends a four-layer system that starts with a two-component epoxy polyamine primer, then has a layer of three-component sand-filled epoxy grout, a layer of three-component sand-filled epoxy polyamine intermediate coat, and a top coating of two-component epoxy novolac. To make this system work requires extensive floor prep to remove the old joint material, scrape off all old surface coatings, degrease the concrete, and shotblast the floor with a walk-behind machine. You might guess that all of this is expensive—the estimate is from $5.50 to $10.00 per square foot and the facility will be out of service for up to 2 weeks. While there may be cheaper coating systems, they are unlikely to last long under your severe requirements. In fact, there may be nothing that will stand up for long to tracked equipment on a daily basis.