KOSTER 21 - Multi Purpose Waterproofing Solutions

KÖSTER 21 : Introduction 

Koster 21- is a water based (solvent free), highly heat reflectivity cementitous waterproofing membrane. It is a multi-purpose liquid waterproofing for masonry, concrete, metal, PVC and etc. KÖSTER 21 means for "waterproofing in the 21st century" where the material has consolidates many advantages among the range of waterproofing products. KÖSTER 21 was designed to cater the demand of the world market, which expects the excellent quality and sustainable waterproofing products for now and then.


kostre 21


KÖSTER 21: Material charateristics

  • Solvent free
  • VOC free
  • Polymer based, no isocyanates or bitumen
  • Two component, fast curing
  • White color, reflects sunlight and heat (reducing necessity for cooling)

KÖSTER 21: Technical characteristics

  • Elastic and crack briding
  • Resistant to pressurized water
  • Suitable for indoor and outdoor use
  • UV-resistant, resistant against salts,hydrolysis, frost
  • Excellent adhesion also to moist mineral substrates
  • Good bonding to a wide range of materials, namely masonry, concrete, metal,  old  bitumen waterproofing materials
  • Density of 1.55 g/m³


KÖSTER 21: Fields of application

  • External basement waterproofing
  • Roof waterproofing
  • Waterproofing under tiles (i.e. in wet rooms)
  • Balconies and terraces
  • Tanks
  • Re-waterproofing for the old waterproofing membrane
  • Stops the carbonation
  • Protection coat against synthetic oils and high-boiling aliphatic hydrocarbons (up to 2 bar)


KÖSTER 21: Application

  • 1.6mm – 2.0 mm total layer thickness (2 layer appliction)
  • Liquid and therefore seamless applied
  • Very easy application by brush, roller, trowel or spray application possible. The consistency can easily be adjusted by adding up to 8% of water
  • Application temperature +5 °C to +35 °C
Koster 21- Water Based/Solvent Free, High Reflectivity Cementitous Waterproofing Coating 

Koster 21- Water Based/Solvent Free, High Reflectivity Cementitous Waterproofing Coating