Prefabricated modified composite polymer-bitumen waterproofing membrane, composed of distilled bitumen and polyolefin elastoplastomeric polymers (APAO) having excellent characteristics. SUPERTEC P and PA are reinforced with a woven non woven single strand composite spunbond polyester fabric, having excellent mechanical characteristics as well as dimensional stability. SUPERTEC PA versions are self-protected on the upper face with mineral slates which reduce heat absorption, improving the durability of the membrane, and has a 10 cm side selvedge and 15 cm head selvedge to promote the adhesion between the sheets. Further available finishes include talc, sand, PE film and polypropylene mat.