Prefabricated waterproofing membrane, composed of a special compound based on modified bitumen with a new generation of elastomeric polymers (SBS), reinforced with a woven non woven fiberglass mat. The upper surface is self protected with a laminated aluminum or copper sheet. The self protection with a metal laminated sheet, besides providing aesthetic characteristics to the product, protects the membrane from atmospheric agents and allow a sufficient reflection of the sun rays, increasing the durability. To allow for a proper bond between the sheets, the protected is supplied with a side selvedge. The characteristics of these membranes are such that the products can be used with success to waterproof a wide range of areas such as civil and industrial buildings, especially for those with aesthetic or architectural requirements.