The composite section (1) has an adhesive tape (2) that is durably bonded to a sealing strip (3). The adhesive tape (2) has a flexible substrate (4) of foam, the first surface (5) of which has a first adhesive layer (6) covered with a pull-off liner (7). A second surface (8) of the substrate (4) opposite the first surface (5) is thermally melted onto a facing surface (9) of the sealing strip (3) and is durably welded with the likewise heated facing surface (9) of the sealing strip (3) to form the composite section (1).