Grp Patch Repair is the installation of a short length of lining material impregnated with resin.It is used in repairing defective sections sewer pipelines. The Patch mandrel is inserted between manholes by winching from one end until the patch mandrel is in the correct position. The Patch mandrel is then inflated with compressed air so that the patch is impressed against the sewer pipe.When the patch repair has cured the mandrel is deflated and removed from the sewer. Patch repairs range from 150mm to 600mm diameter and are 1000mm in length.






