Abstract: Disclosed is a heat-sealed polymeric waterproofing membranes having an upper layer and a lower layer penetrating an intermediate carrier material. The upper layer and the lower layer comprise a copolymer. The copolymer is the polymerization product of the monomer ethylene and a comonomer selected from the group, of vinylesters of a C.sub.2 - to C.sub.3 -alkane carboxylic acids and C.sub.1 - to C.sub.4 -alkyl esters of acrylic acid.These are also described processes for the preparation of the polymeric waterproofing membranes.The polymeric waterproofing membranes may be used for the sealing of buildings and constructions.