The 25kV building is a former electricity control station, now renovated to house workspaces for (new) media companies and visual artists working with new media. The original building was little more than a blank concrete volume with heavy concrete floors supported by a sturdy steel structure. The building's long facade has been demolished and replaced by a completely transparent screen. The only other alteration to the original building has been to fill in the openings in the different floors. In order to create as much lettable floor area as possible, all service spaces (circulation, lifts and stairways, toilet blocks, kitchenettes, and informal seating areas) have been integrated into the transparent facade. This is actually a two-metre-deep steel-and-glass block set in front of the existing building: an extended service block for the workspaces behind and an interface between offices and the world outside.

A range of technical issues had to be resolved in the facade zone. Since most work is done on computers, high daylight penetration is not really a requirement of the firms in the building, but light levels still have to comply with regulations. The partitions separating the corridor zone and workspaces are therefore completely glazed, and the elongated service block too is made as transparent or translucent as possible. The glazed toilet and kitchen units are therefore no gimmick, but are essential for light penetration. The strip of service spaces is also the only escape route. In the event of a fire, the open glazed zone functions as one huge chimney flue to rapidly channel off smoke. To facilitate this, flexible glass lamellas have been placed at the top and bottom of the suspended, transparent zone.

There are no sun-shield elements attached to the transparent zone, since these would have a negative effect on its capacity to admit light penetration. Collectively, the stairways, toilets, kitchenettes, seating areas, structural elements, corridors, and all the other elements in the transparent zone form a natural light filter. Overheating of the open zone is prevented by the lamellas at the top and bottom, which open automatically in response to high temperatures, thereby creating a natural ventilation flow.

Given the completely glazed facade, it would be easy to label the 25kV building as high-tech architecture, but that would be inaccurate. Technology here is kept basic and unfinished. The heavy steel columns in the workspaces are left untreated, and the structure of the facade zone is consciously of the rough-and-ready variety, a far cry from the perfected techno-aesthetics of designers like Norman Foster. One of the most important aims in the design was this informal quality. By concentrating all activities within the zone directly behind the glazed facade, the architect rendered the informal, even cluttered, dynamics of the building's occupants visible through this 'facade screen'. Control over the formal characteristics of the (facade) design is therefore deliberately left to the occupants. A work of art that emphasises this informal quality of the facade is currently being worked on.