Barcelona City Council and the UIA World Congress of Architects 2026 Barcelona have announced the two winning proposals in the international open call “MINERAL. Architectures of Urban Mining“, the urban innovation challenge launched as part of the Research by Design initiatives to seek pioneering solutions for reusing construction waste generated by urban development projects, transforming it into new materials or applications with architectural value.
The initiative, promoted by BIT Habitat, BIMSA, the Mies van der Rohe Foundation, the Barcelona Provincial Council and the UIA World Congress of Architects 2026 Barcelona, has had a significant international impact. The call received 29 proposals, 11 of which came from Catalonia, 3 from the rest of Spain and 15 international, with participants from countries such as China, Turkey, the United Kingdom and Hong Kong.
Each of the two winning teams will receive a grant equivalent to 80% of their budget, with a maximum of €150,000 per team, to implement their innovative proposal.
This funding will enable the proposed solutions to be tested through pilot trials carried out in various initiatives managed by BIMSA in Barcelona during the current year. The prototypes will be monitored for one year to assess the achievement of the expected results. Finally, the results of the research and innovation process will be presented at an exhibition during the UIA World Congress of Architects 2026, as part of the Becoming Circular and Becoming Embodied work streams.
The winning proposal, Spolia, proposes the reuse of large pieces of mineral waste – mainly asphalt and concrete – without the need to separate or transform them, to create new large-format modular construction elements, such as walls or retaining walls. This minimises the handling of materials and significantly reduces the carbon footprint by applying a circular reuse process to the creation of prefabricated elements.
In turn, Grounded Futures will develop new building materials by combining crushed mineral waste from public spaces with a natural binder made from seaweed. The project will explore different types and formats of materials using locally available waste, recycled through a selective process, with the aim of reintroducing them into urban spaces and reducing the carbon footprint of projects.
According to the congress curators:
“The Mineral Challenge studies technologies, spaces and aesthetics that explore the reuse of mineral waste from demolition projects in the city of Barcelona. In the short term, research is focused on developing an industrialised and scalable system through the construction of prototypes and a permanent pilot project. In the long term, the aim is to explore the transformative potential of this construction model, linked to new types of spaces, in order to discover more sustainable ways of building cities.”
The two winning proposals are Spolia, by Belgian architecture studio Baukunst with Structural Xploration Lab EPFL (Switzerland), and Grounded Futures, developed by BC Materials, BC Architects and BC Studies (Belgium).