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Product Information
Technical Datasheet


AT System waterstops have been specially developed for water excluding and retaining structures such as basements, reservoirs, sewage treatment works, etc. The AT System is an important advance in concrete joint protection which combines Active Technology with the conventional mechanical properties of PVC waterstops.

Conventional PVC waterstops work by the normal action of the concrete shrinking away from the joint and against one face of the ribs or bulbs of the waterstop. This creates positive pressure on the rib or bulb causing a “valve action” to resist water ingress. However, this shrinkage movement also forms an inevitable void on the opposite face of the rib or bulb which can allow water under high pressure to track along the waterstop searching for a path to bypass the waterstop. Subsequent cyclical movement of the joint can compound the problem resulting in further leakage.

AT System waterstops mechanical properties prevent water ingress by the same valve action but also actively seal the void around the rib or bulb to stop water bypassing or migrating. The hollow core of the bulb deforms to control the expansive forces to prevent damage to the concrete.


  • Increased security – combines advantages of PVC waterstop with active hydrophilic elements to provide maximum resistance to water pressure
  • Continuously active sealing – hydrophilic elements swell in contact with water to plug voids formed by normal concrete shrinkage
  • Prevents water tracking – location of active element is designed to prevent lateral migration of water along waterstop bulb
  • Engineered profile – for construction and expansion joints
  • Co-extruded section – integral active elements cannot be displaced during concreting
  • Protective coating – prevents premature swelling of hydrophilic element whilst exposed and for 12 to 18 days after casting to avoid spalling of fresh concrete
  • Simple installation – fix and heat weld as conventional waterstops
  • Comprehensive system – internal and externally placed sections complete with a range of factory fabricated junction pieces