The invention is directed to a self-adhering roofing membrane (1) comprising a waterproofing layer (2) comprising at least one polymer P1, a first adhesive layer (3), a barrier layer (4) comprising a polymeric film (4-1) comprising at least one polymer P2, a second adhesive layer (5), and optionally a release liner (6), wherein the first and second adhesive layers (3, 5) are pressure sensitive adhesive layers. The invention is also directed to a fully-adhered roof system and to method for producing a self-adhering roofing membrane.