US Patent 7670086 Method of repairing a manhole chimney using a stretchable sleeve

A method of repairing and renewing a manhole chimney utilizes a circumferentially stretchable liner sleeve which is inserted into the manhole and pressed by an inflatable bladder into engagement with the walls of the manhole chimney. The sleeve is coated with an uncured resin, which is allowed to cure as the sleeve is pressed against the chimney walls, thereby attaching the sleeve to the walls of the manhole chimney. The stretchable sleeve eliminates air spaces between the sleeve and the chimney walls, and precludes formation of undesirable folds in the sleeve. The sleeve stretches circumferentially up to 150% of its unstretched diameter, while having a substantially unstretchable length.