When it comes to roof renovation, liquid plastics are consistently among the recognized and reliable solutions for flat roofs. In new construction, however, other factors are decisive. While no one disputes the functionality and safety of the material here either, conventional materials are primarily used in this segment, mainly for cost reasons. This approach works well for large, uncomplicated surfaces. However, it does not work for complex roofs with numerous structures, connections, and penetrations. These considerations led to the decision to waterproof the flat roof of the Doppel X office tower in Hamburg—built in 1999—using the Triflex ProDetail liquid polymer system. The number of tricky details and complicated connections was so great that they could not be handled using conventional methods—or only at great financial expense.