In 1955, as a result of a competition organized by the Phoenix-Rheinrohr AG Vereinigte Hütten- und Rohrenwerke, Helmut Hentrich and Hubert Petschnigg designed a steel frame building with shear walls with a shape that resembled parallel slabs.

Hentrich and Petschnigg had in mind a “variant of the Pirelli skyscraper”. It was only later, after a joint trip to the United States with Düsseldorf MP Friedrich Tamms, where they were convinced by the advice of their American colleagues that the high-rise office building should be designed in the form of the final solution.

The “three-slice house” gets its name from the fact that it is divided into three rectangular, parallel, offset elements, about 8.5 m wide, the middle one being the highest at 96 meters and 26 floors.

Their full width covers a total of 33,700 square meters of office floor plans. The corresponding access corridors are organized in the “joints” between the partitions and are visible behind the facade return.

The free division of rooms is restricted, especially in protruding end pieces and on the upper floors of the central partition. However, the system allows spaces to be divided into separate offices along corridors or combined into open-plan offices, conference rooms and common rooms. Because of this feature, the three-slice house is considered the prototype of a new office building architecture.