The focus of this sustainability support mandate was on procedural and qualitative issues. Using the holistic refurbishment concept as a basis, Gruner undertook an additional preparatory phase during which enhanced design concept options were prepared. This was necessary in order to do full justice not only to the size and complexity of the project but also to the severe project constraints, which allowed only a short construction window during the summer break. The enhanced concept options made a significant contribution to improving clarity and disentangling the problem areas.