SikaSwell® S-2 is a one-component, moisture-activated polyurethane sealant designed for sealing construction joints and penetrations in concrete structures. It expands upon contact with water to create a durable, watertight seal, making it ideal for basements, water tanks, tunnels, and other below-ground applications. Easy to apply and compatible with the SikaSwell® waterproofing system for reliable long-term protection.