NBS Source
Köster Waterstop


  • Sealing of water leakages in concrete, masonry and natural stone.
  • Can also be used to form fillets which are subject to pressurized water, to seal slotted walls, manholes, cable and pipe penetrations, and to subsequently seal damaged pipe joints in canal construction even if they are exposed to pressurized water.

In order to prevent the escape of moisture from the area surrounding the leakage, it is recommended to coat this region with Köster NB 1 Grey (minimum 400 mm radius around the leakage).

If the substrate is heavily damaged by salt and moisture, the surface should be coated using the Köster KD System.


Expanding plugging and repair mortar for sealing water leakages.

Features and benefits:

  • Fast curing and the slight expansion of the curing mortar ensures an intensive contact between the existing substrate and the mortar is achieved.
  • Cracks bearing pressurized water and water leakages can be quickly sealed.

General information


Pr_20_31_53_96 Waterproof mortarsPrimary


C41/530 Proprietary mortar repairs

C42/310 Repair mortar

Specification data - Waterproof mortars Enhanced data


1.9 kg/L.


1.5 N/mm² and >4.0 N/mm².

After 24 hours and after seven days.

Flexural strength

>1.6 N/mm².


Application of following layer (approximately): Three hours.


Minimum application temperature - substrate


Substrate and surrounding temperature (minimum).