Method and apparatus for rehabilitation of water conduit with lateral openings

A method of rehabilitating a network of underground water conduits 18 which have at least one lateral opening (15, fig. 1) comprises the steps of blocking and sealing the lateral opening with a membrane impregnated with a hardening resin 20. The membrane is positioned over the lateral opening, and the resin hardens to form a rigid membrane over the lateral opening. The membrane can be installed onto an inflatable device (30, fig 3) which is brought into position in front of the lateral opening. Once in position it is inflated, thereby expanding and pressing the membrane into contact with the inner wall of the conduit around the lateral opening. The inflatable device can include a commercial inflatable pipe plug (38, fig. 3) modified to have fore and aft skates (32, 34, fig. 3). The membrane can be wrapped around the inflatable device such that ends of the membrane overlap. The membrane can include a cylindrical plug comprising a cylindrical C-shaped inner spring made of a preformed composite sheet and an outer layer consisting of a fabric sheet impregnated with a hardening resin. The lateral opening can be any of a T-branch 16, Y-branch, cross-section branch, or a localized breach.