Abstract: A sewer pipe, transport pipeline, or other circumferentially enclosed passageway is lined by inserting into and along it a flexible tubular material of given diameter, with its corresponding circumference being less than the inside perimeter of the passageway. The tubular material is a laminate having a dimensionally stable skin layer facing the interior of the passageway and a contiguous layer of a composition foamable to form an expanded cellular structure. After insertion of the tubular material the contiguous layer is foamed to expand cellularly so as to fill the space between the inner skin and the inside wall of the passageway and to solidify in place. The tubular material may have an expansible outer skin layer also.