Multifunctional waterproof product with excellent adhesion to both dry and damp substrates. KÖSTER 21 is a 2-component, solvent-free, liquid-applied, flexible, and crack-bridging material. It is applied in liquid form, making it seamless and especially suitable for use in complex architectural details. Thanks to its UV stability, it is suitable for both indoor and outdoor applications. The white color reflects sunlight and reduces surface temperature of the structure. The fast-curing coating is highly flexible and resistant to pedestrian traffic, aging, hydrolysis, UV radiation, frost, and salt.
KÖSTER 21 provides sealing against synthetic oils and aliphatic hydrocarbons with high boiling points (up to 2 bar). KÖSTER 21 is not resistant to substances with a high content of aromatic hydrocarbons, such as benzene, xylene, toluene, etc. For specific inquiries, please contact our technical support team. KÖSTER 21 contains no volatile organic compounds (VOC content = 0) and is free from polyurethanes, isocyanates, and bitumen.