#SustainableHub is the Permanent Representation for Sustainability to the EU. A co-working space aimed exclusively at companies that are pioneers in sustainable development, it is based in a former diocesan building renovated between 2002 and 2004 by the studio architectesassoc+. The building is situated on a narrow plot, 15 meters wide, in the heart of the Leopold district. Designed according to the typological theme of a “townhouse” with a pedestrian carriage entrance, the program includes a dozen meeting rooms and offices dedicated to the center itself. These functions are organized between two existing adjoining buildings, extending from the basement to the first floor around a private inner courtyard. The natural light brought in by this design floods the rear volumes, which include communal spaces such as the staff cafeteria. The four upper levels house office functions in the form of stacked landscape duplexes, with staircases articulated along the street facade. The entire structure is connected by a vertical mechanical circulation core attached to one of the adjacent buildings, where all floor services are also grouped. This arrangement frees up the workspaces, which are designed to be transparent. The full-height glass facades enhance this effect. During the design process, the architects worked with Belgian artist Jean Glibert, who died in January 2024. The building sits on a narrow plot of land, being only 15 metres in width, in the heart of the Leopold Quarter. The fact that it is made almost entirely of glass means that natural light is present throughout the building, even in the basement. The centre has around 10 meeting rooms and offices, nestled between two independent party walls and organised around a private interior courtyard. The building’s main feature is its brightness, thanks to the floor-to-ceiling transparency of its façades. The range of materials used is limited and puts a premium on translucency: exposed reinforced concrete, steel beams and galvanised steel ventilation tubes. Glibert, a major practitioner of integrating artworks into architecture and public spaces in Belgium, worked on various parts of the building. He installed red perforated steel sheets that wrap around the lift and the stairwell, creating a sort of red airlock. This solution radiates a constant coloured halo, a fluorescent light diffused through the tiny perforations. Ceilings and exterior porches are treated in the same way. The overall effect is a serene atmosphere of light and colour.