A support assembly for supporting one or more photovoltaic modules on a support surface, such a generally flat roof, is disclosed herein. The support assembly includes a ballast tray configured to accommodate one or more ballasts; at least one tubular member coupled to the ballast tray, the at least one tubular member configured to support one or more photovoltaic modules above a support surface; and at least one clamp member coupled to the at least one tubular member. In one or more embodiments, the support assembly further includes at least one channel member coupling said at least one tubular member to said ballast tray. A mounting system including a plurality of support assemblies is also disclosed herein.