An apparatus and method for repairing the junction of a sewer main line and a lateral pipe includes a generally T-shaped flexible translucent urethane inflatable bladder having a main line portion and a lateral portion. The lateral portion is inverted through the main line portion and extends out one end thereof. A liner assembly of resin absorbent material is formed, with a tubular lateral liner connected to a flat sheet main liner, at a central opening in the flat sheet liner. Each liner is coated with a polymer coating, for an airtight seal, and a polymer tape is welded to the polymer coating on the lateral liner and the junction of the lateral liner and flat sheet, to form airtight seals. The liner assembly is then installed in the bladder assembly, by threading the lateral liner into the lateral bladder until the flat sheet contacts the main line bladder. The lateral liner is then impregnated with uncured resin and the liner/bladder assembly is installed on launcher. The flat sheet liner is also impregnated with uncured resin, and the launcher is then inserted in a sewer main line and aligned with a lateral pipe to be repaired. The lateral bladder is inflated to revert the bladder upwardly into the lateral pipe forcing the liner assembly into contact with the lateral pipe, the main line sewer pipe, and the junction thereof. Once the resin is cured, the bladder assembly and launcher are removed from the sewer pipe.
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