A load support structure supports a load on a metal panel roof, such that substantially all of the load is conveyed through rails, which are mounted on roof panel ribs. Lateral closure members extend about, and define, the load support structure. Cavities are provided in the lateral closure members. Thermal breaks extend upwardly from the roof opening, through the tops of the closure members. Such thermal breaks are provided by a combination of thermal product in the closure member cavities and by strategic placement of edge portions of underlying roof insulation.