This project brings together the concepts of sustainability and mixed-use inner-city development to maximise the potential of both. It not only combines apartments, offices, shops and restaurants within a single complex, but also provides a structure that allows individual units to be easily adapted from offices to apartments should demand for office space in Cologne fall.

Germany's enlightened legislation on working conditions promotes the individual's right to daylight and thus the design of office buildings with relatively shallow floor-plates. There need be little difference, therefore, between the basic configuration of an apartment or an office building, except for the provision of bathrooms and kitchens. Accordingly, all the offices in the Gerling Ring are naturally ventilated and have raised floors, which means that they can be easily converted into apartments, avoiding the environmentally wasteful alternative of demolition.

Like the configuration of the building's basic plan, the technological and environmental elements of the complex are highly adaptable and energy efficient. For example, the prefabricated concrete elements that form the ceilings perform a variety of roles: their vaulted profile creates a deep void at the centre of the plan for the incorporation of kitchen and bathroom services, and a shallow space for heating and electrical installations along the facade. The ceilings also reflect natural light into the interiors and, combined with fresh air intake, their high thermal mass helps to maintain comfortable temperature levels in summer. Similarly, the building's double-skinned facades, with black and white adjustable louvres, provide further passive environmental control.