PARAGUM ST prefabricated waterproofing membranes are obtained by coextrusion of a compound, based on elastoplastomeric bitumen-polymer with base of metallocene resins, derived from the special PARALLOY component (widely known for its superior technical and performance characteristics), and a composite reinforcement in nonwoven polyester with a continuous filament stabilised with glass fibres, inserted in the thickness of the membrane in complete synergy with the same.