TGL-SP’s Expandable waterstop strip is designed to stop water infiltration through concrete construction joints. It expands immediately upon first contact with water and fills the void and cracking, forming filler throughout the leaking path that seals against the concrete walls. At the moment of hydration, the seal expands up to three times its size in an open area but is limited to controlled expansion within the concrete joints. The effectiveness of this durable waterstops is achieved by high content of sodium bentonite mixed with butyl rubber, which provides outstanding swelling performance. It is designed to replace commonly used plastic or rubber waterstops by eliminating the need for additional metal segments and frame-work.