TERMOSYSTEM ONDA is a system made up of a waterproof bituminous membrane and an EPS or EPS insulating panel, with graphite additive shaped according to the type of cement fibre or asbestos corrugation, on top of which it is laid. In the case of vault roofs TERMOSYSTEM ONDA is suitably precut. The panels are provided with two overlapping selvages on the two perpendicular sides.