A roofing panel includes a front surface, a top surface, a bottom surface, a right-side surface, a left-side surface and a rear surface, the front surface, the top surface, the bottom surface, the right-side surface, the left-side surface and the rear surface include a waterproofing membrane. The crystal silica content of the so-formed foamed glass body is less than 1 weight percent. The airbag includes internal vents configured to allow selective communication between the first chamber and each of the at least one second chamber and the at least one third chamber and selective communication between the at least one second chamber and the fourth chamber.