The rerounder is a hydraulic tool that restores deformed pipes of concrete and clay without excavation.

A steel sleeve is mounted on the rerounder and, monitored by a TV camera, the hydraulic tool is drawn to the deformed pipe section. When the rerounder has been positioned correctly, the steel sleeve is hydraulically pressed against the pipe wall. In the process the deformed pipe section is pressed outwards and the pipe regains its original cross section.

The pipe section subsequently has to be relined.