When pipes are damaged by continuous cracks of a structural type, strong static deterioration or chemical attacks, the whole of the damaged length must be recreated, working through pits without creating problems at surface level. Our “liner” system quickly lines the deteriorated pipe from the inside. The self-supporting lining consists of a polyester or glass fibre sheath impregnated with special resins and is enclosed within a system of high-density polyethylene films. The impregnated sheath is inserted into the damaged pipe and expanded through water or steam pressure in order to adapt it to the existing pipe; it then becomes fully hardened and structural by water or UV technology heating. Our system ensures uniform thickness of the lining, with only the slightest narrowing of the original pipe diameter, an increase of hydraulic propertys and very strong, long-lasting repair.