When designed and installed properly, following ACI 330 Standards, there is no downside to a concrete parking lot, period." That doesn't mean there aren't obstacles to overcome, Swederski admits.

Alternatively, specifiers should refer to ACI 330.1-03 "Specifications for Unreinforced Concrete Parking Lots" which does not use F-numbers but recommends a ½-inch gap under a 10-foot unleveled ...