US Patent 6948716 Waterstop having improved water and moisture sealing features

An improved waterstop having the important added feature of a hydro expansive compound which expands when subjected to water. By expanding, the hydro expansive compound effectively blocks the passage of water that leaks into the gaps created during the shrinkage of the concrete surrounding the improved waterstop. All that is required are narrow strips of judiciously positioned hydro expansive compound at opposite ends of the improved waterstop.