A properly designed concrete overlay can provide many years of low-maintenance service. Elements key to good whitetopping design include adequate pavement thickness, concrete strength, drainage, and jointing. Preparing proper construction specifications for concrete parking lots has been made much simpler with the publication of ACI's "Standard Specification for Plain Concrete Parking Lots" (ACI 330.1). This standard covers the minimum requirements for the construction of plain (unreinforced) concrete parking lots on grade, including materials, placing, texturing, curing, jointing, and opening to traffic. ACI 330.1 is appropriate for use on whitetopping projects with certain modifications to the joint depth and spacing.