Prefabricated thermal activated composite waterproofing membrane, composed of distilled bitumen and special synthesis polymers, which provide thermal adhesion properties to the lower face waterproofing compound. The waterproofing compound of the upper face allows for fast heat transmission to the lower face. The thermal activated waterproofing compound allows the product to be positioned and applied without the initial use of heat and is particularly indicated for those surfaces where the use of direct open flame is not suggested.