“25kV-Gebouw”, the name of this office development, recalls the former use of the building, which originally housed the transformers of a Dutch energy concern. The block dates from the 1950s and has a steel skeleton-frame structure. The terms of the competition brief required the closed concrete facades to be opened up and the internal space to be flexibly converted into offices. Robert Winkel’s winning scheme proposed opening the street front completely and suspending a two-metre-deep glazed projecting structure from the existing facade. This newly gained space contains opaque glass boxes housing tea kitchens and sanitary facilities. The facade was to function like a screen on which moving images of the activities within the building would be visible to passers-by in the street. For the people working in the offices, the space between inside and outside provides an ideal location for a short break or for a chat with colleagues. Ventilation louvres in the floor and roof of the projecting structure ensure a pleasant atmosphere within this space at all times, where one has a sensation of being in the open air. The louvres have a further purpose. In fire trials, smoke was blown into the building, and it was proved that the smoke extraction system functioned efficiently and the escape routes could be used without reservation. It was possible, therefore, to design the projecting structure with spaces extending over a number of floors without dividing them into separate fire compartments.