Abstract: The new, remote-controlled installation of sheathing into inaccessible manifolds and junctions from subsidiary into main piping makes it possible to repair damaged intersections cheaply, rapidly and reliably, without the intersection having to be exposed by excavation. An application device (1), which is installed on a pipe-repairing machine, makes insertion of a lost sheathing (4) into the subsidiary piping (8) possible. The cavity (12) which comes about in this way between the sheathing (4) and the damaged part is subsequently sprayed with specially suited sealing mass by means of a high-pressure nozzle (13).