Pallets containing freshly-poured products are transferred to rack units for curing. The racks are serviced by a fully automatic, computer-controlled stacker. To ensure optimum use of factory floor space the pallets are stacked vertically. The stacker is shifted to the appropriate bay and stacks and destacks the pallets. To meet customers' specific requirements there are various versions of the stacker and, if required, the rack units can be equipped with heating systems.