Abstract: A waterstop repair method and structure for use in both new and existing concrete structures in which a reinforced neoprene diaphragm is anchored to the concrete structure using corrosion-resistant anchors, fiberglass hold-down strips and polyester felt adhesive strips saturated with epoxy adhesive. The diaphragm is supported by a pressure injected hydrophylic urethane foam which is pumped beneath the diaphragm which thereby provides support for the diaphragm and fills the interstices of the existing concrete joint to prevent water leakage in and around a failed waterstop and to thereby form an integral, water-tight structure for new and existing concrete joints.