A portland cement-based, high-strength, fast-setting, non-shrink, self-leveling underlayment. Mix with water, pour or pump, spread, ready! For use over concrete, metal, terrazzo, ceramic tile, wood and old flooring adhesive residue (including cutback), on above or below grade. Installs from featheredge to 1 1/2” in one operation; up to 5” with the addition of proper aggregate. Designed specifically for fast leveling of floors, ARDEX K-15 provides a durable, flat and smooth floor surface with minimum labor and installation time. ARDEX K-15 hardens quickly by hydration and drying. It will not shrink, crack or spall, even when applied in thick layers. Floor coverings can be installed just 16 hours later. 4100 psi. Coverage: (per 55 lb. bag) Approximately 60 sq. ft. at 1/8” thickness.