Insulating panel for roof coverings

A process for the production of a roof with a plurality of insulating panels, each panel comprising a core layer of a synthetic foam material bonded adhesively on its topside to a sealing thermoplastic layer or sheet throughout the surface area of the topside for the covering of roof structures, said core layer comprising at least two superimposed foam sheets of an elastic, closed-cell crosslinked polyolefin foam material, said sheets being bonded together throughout the contacting surface areas by flame laminating, the bonding surfaces of the foam sheets initially melted by said flame laminating together constituting a homogeneous polyolefin layer, which comprises mechanically joining the insulating panels to a substrate in a force-locking manner, joining the abutting insulating panels in rabbet joints, sealing off the butt joints of the insulating panels on the topside with sealing strips by adhesively bonding the panels together, and establishing a force-locking connection in the joints of the abutting insulating panels by the introduction of an adhesive and/or by welding.