Two-component polyurethane system, fast-reacting foam resin when in contact with water, the resin reacts to form an elastic expanding foam barrier that blocks the flow of water in leaking cracks. Uniguard Xtreme PU Water Stop is suitable for bridging cracks of width > 0.2 mm. Using Uniguard Xtreme PU Water Stop in conjunction with Uniguard Xtreme PU Inject provides an effective system for permanent sealing of cracks in wet conditions.