Köster 21 is a multi purpose waterproofing product with excellent adhesion to dry and moist substrates. It is a 2 component, solvent-free, liquid applied, elastic and crack bridging material. Köster 21 is liquid applied and therefore seamless, which greatly eases application to complicated architectural details. Due to its UV stability it is suitable for indoor and outdoor use. The white colour reflects sunlight and reduces building surface temperatures. The fast curing coating is highly flexible, resistant to occasional foot traffic, aging, hydrolysis, UV-rays, frost, and salt.

Köster 21 seals against synthetic oils and aliphatic hydrocarbons with high boiling points (up to 2 bar). Please note that Köster 21 is not resistant against substances with high aromatic hydrocarbon contents such as benzene, xylene, toluene, etc. In case of questions contact our technical support team. Köster 21 does not contain volatile organic compounds (VOC content = 0), is free of polyurethanes, isocyanates, and bitumen.

This product can be sued as positive side waterproofing of basements, concrete slabs, in tanks, on flat roofs, underneath tiles, on terraces or balconies, and similar applications. Köster 21 is suitable for the protection of surfaces in facilities with chemical and mechanical demands on the coatings, such as containment and skimming tanks. This material bonds well to a wide variety of substrates, including: masonry, concrete, screed, PVC, metal, and bitumen. Consumption = approx. 2.5 – 3.0 kg / m². Do not exceed layer consumption by more than 100%. Packaging = 20kg (2 part: A=8kg, B=12kg)