Abstract: A curable liner tube, once inserted into a pipe and cured, can withstand relatively high internal pressures as well as relatively high external pressures, and can also resist destructive effects from liquids and gases with which the pipe and liner tube come in contact. The liner tube is sufficiently pliable in an uncured condition to lie substantially flat and to be substantially circular in cross section in an expanded state, and comprises an outer strengthening system that is configured for placement in a pipe interior and that changes from a pliable condition to a hardened condition upon curing, and a membrane system disposed inwardly relative to the outer strengthening system when placed in the pipe interior, comprising an impermeable sealing film having a facing surface that faces the interior of the pipe.