Caruso St John Architects has won an international competition to transform a 1970s Brutalist office block in Brussels
The London practice – working with local firm Bovenbouw Architectuur – has been selected to convert the former headquarters of the Royale Belge insurance company into a 42,000m² mixed-use complex.
Other finalists in the competition, which received 51 entries, included Dominique Perrault Architecture of Paris, Brussels-based V+ and Agwa, and FVWW architecten of Antwerp.
The £34 million project, planned to complete in 2023, will see the enormous Sovereign 25 building in Brussels’ suburban greenbelt restored and converted into offices, a hotel and residential with a sports club, co-working space, restaurants and a conference centre.
The winning scheme retains as much of the building as possible and will deliver a series of interventions to open up the lower floor levels. The complex was designed by Pierre Dufau of France and René Stapels of Belgium as a single headquarters but has been disused since 2017.
The appointment comes two years after the Stirling Prize-winning practice won an international invited competition for a landmark new 60,000m² headquarters for publishing giant Gruner + Jahr in Hamburg.
Caruso St John Architects’ competition-winning proposal to transform the 1970s Brutalist office block in Brussels
Bovenbouw Architectuur and Caruso St John’s proposal is based on the strategy to retain as much of the building as possible and to transform the ground floor into a lively reception area with a clear orientation towards the back of the building. In order to visually open up the building in depth, the marble walls are slid backwards and a large circular and intensively planted void is created that connects the various parts of the plinth both horizontally and vertically. In order to strengthen the connection between the building and the park, the design team proposes creating green pockets and inner gardens in the deep plinth and making the façade more open. In this way, the former car park at +1 is provided with daylight and, by integrating an outdoor swimming pool and wellness function, provides a subtle connection to the landscape behind the building. The existing entrances and exits for motorised traffic will be retained. A new entrance is planned to make the open floor underneath the restaurant easier to access.
The advisory committee appreciates the choice of the design team to focus on the essential, and through a few well-considered and strategic interventions immediately focus on the ‘heart of the matter’. The proposal attaches great importance to the legibility of the spaces and makes subtle use of landmarks and sightlines for this purpose. The new cylindrical core, together with the auditorium and the marble core, forms a new diagonal axis through the building that marks an internal route through the pedestal and intuitively connects the north and south sides of the site. The advisory committee is positive about the team’s design attitude towards the existing patrimony and assesses the proposed interventions as functional and professional. The approach shows a great deal of sensitivity to the exuberant traits of this Modernist building.