Abstract: Composite panel for obtaining waterproof roofings comprising two superimposed layers firmily held or bond together: one layer is made of a heat-insulating material having a thickness ranging from 10 mm to 60 mm and the other is made of a waterproofing material from 1 mm to 10 mm. The method of laying composite panels includes arranging panels on a supporting structure, fixing the panels to the supporting structure by means of mechanical anchoring means, sealing the seams between the panels and laying of a waterproofing membrane or mantle on the panels.