Flexible seal forming member

A method for forming a non-temporary watertight seal between a pipe and a wall, comprising:

• providing the wall forming part of a storm drainage system, the wall bearing an opening forming an inner surface;
• positioning the pipe having an outer surface through the opening resulting in a gap between at least a portion of the outer surface of the pipe and the inner surface of the wall;
• positioning a flexible member around at least a portion of the pipe and at least partially in the gap such that the flexible member does not overlap itself, the flexible member being expandable and including a layered polymeric patch thereon, the flexible member comprising at least one polymeric material and is configured to have an interior chamber, the flexible member including at least one stem positioned through the layered polymeric patch and being in fluid communication with the interior chamber;
• filling the flexible member with a with a viscous material under pressure to expand the flexible member forming a watertight seal between the pipe and the wall;
• and
• allowing the viscous material to cure and harden to form a non temporary solid plug wherein the flexible member serves as a gasket between the pipe and the solid plug and serves as a gasket between the solid plug and the wall to form the watertight seal.