Loose-fit or Close-fit Lining

Some lining approaches may be designed to be loose-fit or close-fit according to project needs. Lining approaches that were developed to provide only close-fit solutions are grouped separately.

A loose-fit liner is one for which the outside diameter of the inserted liner is significantly smaller than the inside diameter of the host pipe or one where the liner (or hose) is only laid loosely within the host pipe. Using a loose-fit pipe facilitates insertion of the pipe but means that there will be a substantial reduction in the diameter of the renovated pipe. Loose-fit pipe liners are often grouted in place after insertion with a non-structural grout. If the grouting process provides a structural function (linking the liner and the host pipe), then the resulting liner could be considered a close-fit liner. Likewise, an inserted hose liner that is adhered to the host pipe results in a close-fit liner in contrast to a non-adhered hose liner which is considered a loose-fit liner.