The city council sought to demonstrate leadership in circular construction by building a City Hall that followed C2C and circular principles to minimise waste and promote material reuse. Because of this selective approach, stakeholders were constantly challenged during the design phase to identify the best material choices and achieve high circularity and sustainability, while navigating the constraints of scalability and cost-effectiveness for a project of this magnitude.

C2C-certified materials were chosen for their transparency, recyclability, and renewability, avoiding non-recyclable options.

The building was designed for disassembly, with materials treated to enable future reuse. Spaces were designed for multi-purpose use, enabling the building to adapt to changing needs over time.

The building included a 200 m² interior green facade and the world’s largest exterior green facade, purifying indoor and outdoor air while supporting biodiversity. In parallel, rainwater and wastewater management systems minimise resource usage and enhance ecosystem services.

Kraaijvanger devoted considerable resources to knowledge sharing among partners during the design and construction phases.

The building functions as a material bank, retaining financial value in its components for future reuse. Material passports were created to document all building elements' composition, properties, and disassembly instructions, ensuring long-term reuse and recycling.

The building is energy-neutral and waste-free. The green facade absorbs 30% of local air pollutants, offsetting traffic emissions and enhancing biodiversity.

In addition to environmental impacts, the open-house concept provides 630 flexible workspaces, a theatre, a cafe, and public gardens, fostering community interaction and well-being. The building’s design also improves indoor air quality, creating a healthier workspace.

Economic-wise, circular design strategies resulted in an 11.5% return on investment over 40 years, equating to €16.8 million. Residual material value and design-for-disassembly strategies are projected to save €175,000 annually.

Material passports established a replicable model, and the project spurred advancements in C2C practices, with suppliers obtaining certifications and adopting lifecycle-oriented approaches.