Information Session: Circular Transformation in Slotervaart

Transformation of the former Slotervaart Hospital into Het Slotervaart

The former Slotervaart Hospital, built in the 1970s—a complex with over 50,000 m² of gross floor area—went bankrupt in 2018. Real estate company Zadelhoff purchased the building and agreed with the City of Amsterdam that it would retain a social care function. The building was repurposed as Het Slotervaart, a space where diverse care functions converge. Thanks to the sustainable ambitions and the integrated collaboration between design, engineering, and construction, the existing building could be largely preserved and serve as the starting point for the transformation. The renovation was carried out with a strong focus on circularity and material conservation.

Preservation as the starting point for both design and implementation

From the outset, the client, Zadelhoff, had a circular ambition. At Het Slotervaart, this circular ambition was translated into an integrated approach in which a comprehensive materials inventory served as the basis for the design. The design team, led by the architectural firm INBO, noted that preserving and reusing the existing building would not only yield the greatest CO₂ savings but was also the most financially sound choice. Moreover, this approach made it possible to keep parts of the building in use during the renovation, thereby ensuring the continuity of care services.

“Zadelhoff is intrinsically motivated to use its buildings to contribute to a sustainable society and to preserve unique properties in the greater Amsterdam area.” – Lieke van der Wal, developer at Zadelhoff

Jeroen Simons and Jeanne Leung, both architects at INBO, explain: “Characteristic exposed concrete elements such as the window-cleaning balconies, cassette ceilings, and service shafts have been preserved and reused as much as possible. The building’s structure—featuring columns in the lower six stories and load-bearing walls in the upper sections—has also been functionally adapted for its new use.”

In addition, many of the existing pieces of furniture, tools, heating panels, stair railings, and wooden bed rails in the inpatient wards were reused. Much of this has been repurposed at Het Slotervaart or incorporated into works of art, for example.

Collaboration between developer, design, and construction

The following parties were involved in the building's renovation:

• Client: Zadelhoff
• Contractor: Medicom Zes
• Architect of the existing building: INBO
• Architect: MVSA Architects
• Users: tenants of Het Slotervaart

A real-world example with lessons for the entire industry

At the same time, the team also recognized that there was still room for improvement in the sector when it came to applying circular principles more systematically in projects. Among other things, better material inventories, practical craftsmanship, and a way to sustainably preserve knowledge would help raise the “circular” bar even higher—including in other projects. In addition, according to Jeroen Simons, architects can further develop their skills in designing for disassembly and reuse. At Het Slotervaart, they successfully harvested some of the concrete gravel elements into aggregate, which was then used as circular concrete in other projects.

What makes Het Slotervaart a successful case study? According to Zadelhoff and INBO, it is the client’s intrinsic motivation, combined with an integrated team in which architects, consultants, and contractors work closely together and demonstrate flexibility and craftsmanship in making use of the existing building.

MOOI Consortium

Circular HVAC Systems is a multi-year MOOI project in which DGBC is collaborating with 18 organizations—including Circonnect—to develop circular HVAC systems, with the aim of significantly reducing the environmental impact of these systems. The research program will run through June 2027.