Abstract: A sewer (1) is relined by introducing a flexible tubular waterproof membrane (4) and then inserting a pipe or pipe length (5)(5a)(5b) into the tubular membrane (4). Grout (10) is then introduced between the sewer (1) and the membrane (4). A further membrane (7) may be provided so that the grout (10) is located between the two membranes (4,7). In the case where the sewer (1) includes an opening for a lateral connection (11), the grout (10) extending across the opening can be removed. Alternatively the grout (10) can be prevented from extending across the opening. Another tubular membrane (8) may be located within the pipe lengths (5)(5a)(5b) to be filled with water during the introduction of the grout.

Abstract: An existing underground sewer or other pipe is renovated by rupturing and radially expanding the pipe and installing a replacement pipeline within the ruptured pipe. The pipe is ruptured and radially expanded by introducing a plurality of radially expandable tubular members into the pipe so as to form a liner. Each member is then radially expanded so that the liner engages with and then ruptures the portion of the pipe adjacent thereto. The tubular members may be radially expanded by inflating a bag within the confines of the members.