Home > Companies > Delta Membrane Systems Ltd > Köster NB 1 Grey Slurry


  • Mineral coating containing crystallizing and capillary-plugging agents.
  • Excellent resistance to pressure, abrasion and chemicals.
  • Highly effective waterproofing with bituminous building materials.


  • Waterproofing against ground moisture, non-pressurized and pressurized water.
  • New building and in the repair for horizontal and vertical waterproofing of concrete, masonry or cementitious plaster in wet rooms, bathrooms, showers, new-built basements, tanks, silos, sewage treatment plants, manholes, drinking water tanks, etc.
  • Application should only be carried out on substrates that are free from moving cracks.


- Köster Polysil® TG 500:

Recommended for use on highly and normally absorbent and dusty or salt-damaged substrates.


  • Negative side waterproofing: Mix with water.
  • Positive side waterproofing: Mix with recommended additive.

Standard product features

Coating system (minimum):

Two coats.


  • Positive side waterproofing: 1.5 kg/m² (minimum, one coat); 4 kg/m² (maximum, 2–3 coats).
  • Negative side waterproofing: 3 kg/ m² (two coats).
  • Combined system-waterproofing with bituminous building materials: 1.5 kg/m² (one coat).

Density of fresh mortar:

1.85 kg/L.

Compressive strength:

  • After seven days: > 20 N/mm².
  • After 28 days: > 35 N/mm².

Flexural strength:

  • After seven days: > 4.5 N/mm².
  • After 28 days: > 5.5 N/mm².

Adhesive tensile strength:

> 4.5 N/mm².

Waterproof against pressurized water:

< 13 bar.


  • Resistance to foot traffic: After two days (approximately).
  • Full cure: After 14 days (approximately).



- Köster NB 1 Flex:

  • A latex based dispersion which is intended as a mixing liquid for Köster NB sealing slurries.
  • It has an elastifying effect, improves the adhesion to the substrate and prevents the premature drying out of the fresh slurry.

- Köster SB-Bonding Emulsion:

  • Added to the mixing water to raise the ability of the waterproofing system to retain water.
  • Prevents, in cases of unfavourable weather conditions (warm, dry, drought), a premature curing of the coating.
  • Introduces flexibility to the material.

NBS Specification

NBS Create logo
This product is associated with the following NBS Create clause:
45-55-50/460 Crystallization active slurry mortar

NBS Specification

NBS Buliding logo
This product is associated with the following NBS clauses:

Product specification

An important note about specifying



Delta Membrane Systems Ltd


+44 (0)1992 523523

Product reference

Köster NB 1 Grey Slurry


[Not required]
[Köster NB 1 Flex]
[Köster SB-Bonding Emulsion]

Manufacturer details

Delta House,
Merlin Way,
North Weald,
Essex, CM16 6HR
Tel +44 (0)1992 523523
Fax +44 (0)1992 523250
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NBS National BIM Library