Waterstops

Waterstops made of thermoplastic or elastomer are used for sealing expansion and movement joints as well as construction joints. The sealing effect of concrete-embedded waterstops follows the labyrinth principle. This principle is based on a considerably longer water circulation path with frequent changes of direction. It works for PVC-P, PVC/NBR and elastomer waterstops with a profiled surface. The sealing is effective transverse to the ribs, whereby several small ribs or a few large ones can be arranged. Both the labyrinth and embedding principles are used for elastomer tapes with steel straps. Clamped waterstops suitable for sealing joints between existing structures and new concrete structures are an exception. These waterstops seal the existing structure using contact pressure, while also sealing the new structure by means of the labyrinth principle.

Movement joints

Waterstops with a central tube are available on the market as external and internal tapes for sealing joints with expansion and shearing movements. Movement expansion waterstops normally consist of an expansion part and a sealing part. The expansion part is designed to absorb the water pressure and the differences in movement of the adjacent components. The dimensions and shape of the expansion part must be selected according to the stress on the joints. The sealing parts are designed to prevent water from circulating around concrete-embedded waterstop junctures. The expansion and sealing parts are usually separated by anchoring ribs. Their purpose is to transfer all tensile forces in the waterstop into the expansion part and into the concrete, so that the sealing part remains largely stress-free.

Construction joints

External and internal waterstops are used to seal construction joints. However, internal waterstop tapes for construction joints should never be subjected to shear strain. If there is no joint gap, joint movements across the tape can lead to shearing and thus to the destruction of the tape, regardless of the material of the tape.

Waterstop materials

Different materials are used for waterstops depending on the type of waterstop and water pressure load.

The essential characteristics of the material are:

Elastomers are dimensionally stable, highly elastic plastics with very long interlocking molecule chains. They are produced using a vulcanisation process and therefore require a special type of joining technology.

They are particularly suitable for buildings with large joint movements, high water pressure, frequently changing load cycles and also at low temperatures.

They are available in all major profile shapes and for many special applications.