GRP lining is a hose relining method in which the inliner used is a seamless glass fibre fabric hose. GRP lining can be used to rehabilitate sewers with damage such as root penetration, deposits, socket offset, cracks and pipe fractures.In contrast to passive sealing systems such as conventional water stops and waterstop sheets, which only seal off due to the so-called circumference extension, active systems such as injection hoses and injection grouts can be used to cancel out possible weak points in the concrete caused by cracks or badly compacted concrete.