Sherpal L : Weighted support systems for technical equipment on flat roofs. Sherpal ballasted is a support structure which allows the installation, without drilling, of technical equipment on the waterproofing membrane of a flat roof. Sherpal ballasted is designed to support specific equipment: VMC, air conditioning units, heat pumps, inverters, antennas or projectors. It can also be used to circulate ducts, cable trays or pipes.