For the social area of the Postal Welfare Office, approximately 1,500 m² of base area should be spanned column-free.
The range of boundary conditions (planting, types of foundation, optimum height, daylight requirements etc.), predefined the design of a concrete shell whose geometry was determined by inversing a hanging form as a membrane shell from the fixed loads. This way, the thickness of the shell could be limited to 12 cm and the maximum height of the garland-shaped edge beams could be limited to 40 cm. Only the shell base had to be thickened as the membrane-bearing effect could not be maintained here due to lack of space.