A mono-component liquid applied roof waterproofing kit based on water dispersiable polymers. It consists of water dispersiable styrene – acrylic copolymers, is elastomeric, and has an internal reinforcing mesh made of fiberglass. The kit, once polymerized, conforms an elastic lining, in form of a layer completely bonded to the support. The minimum layer thickness of the assembled membrane has to be 1,3 mm.