Partially waterbearing cracks in the stairway (until 4 levels below the surface) and the service and cable shaft of this metro station near the acropolis in Athens were waterproofed. The injection resin KÖSTER KB 2 IN 1 was the ideal product for this project. If the material comes into contact with water, it reacts to form a highly elastic foam. Under dry conditions, the material reacts to form an elastic solid body resin.