Flex 2K is a two-component cement-based mortar. Component A is a mixture based on cement, selected fine-grained aggregates, fibres and specific additives. Component B is a mixture of highly flexible acrylic polymers in water dispersion. Once the two components have been mixed, a mixture having excellent workability is obtained, easily applied with a construction trowel, even vertically without dripping and scraps, with excellent adhesion to the substrate. It is resistant to frost-thaw cycles and thawing salts, and has excellent resistance to the spread of CO2. It keeps excellent elasticity even at low temperatures. Flex 2K is a liquid-applied waterproofing product to be used under ceramic tiles bonded with adhesives according to EN 14891 classified as type CM O2 P and is a surface protection coating according to EN 1504-2 type C and class PI, MC, IR according to EN 1504-9. Once installed, the product meets the requirements for class E construction materials according to DIN EN 13501-1.