The construction sector is moving towards increasingly circular and sustainable models. In this context, SPOLIA was born, a construction solution developed by Baukunst, Structural Xploration Lab (EPFL), Sorigué and Schlaich Bergermann und Partner. 

Sorigué’s Urban Spaces Catalonia team has contributed its technical expertise and delivery capacity to build the first SPOLIA prototype, which is on display from 26 June to 19 July at Les Tres Xemeneies, the former thermal power station in Sant Adrià de Besòs, as part of the UIA World Congress of Architects 2026 in Barcelona. 

SPOLIA, one of the winning proposals of the international “Mineral. Urban Mining Architectures” challenge organised by the Fundació BIT Habitat, stems from the concept of urban mining: the city understood as an active quarry and materials bank capable of supplying new constructions. 

This ongoing research project responds to the high volume of mineral waste generated by urban renewal in the Barcelona metropolitan area. Its objective is to demonstrate that it is possible to build by reusing large pieces of waste—primarily asphalt and concrete from public roads—without the need to separate or transform them beforehand. 

The result is a modular, prefabricated system that gives a second life to materials generated in urban redevelopment works, reducing resource consumption and the carbon footprint compared to conventional solutions based on new concrete. A commitment to decarbonisation and urban circularity that seeks to advance towards a construction model based on circular economy principles. 

The project goes beyond the technical goal of reducing environmental impact. SPOLIA also seeks to highlight the aesthetics of recovered materials, showcasing the reused fragments. This results in a construction element of great visual richness and heterogeneous texture, which adds character to the space and demonstrates that sustainability and architectural quality can go hand in hand. 

The exhibited prototype has been created using concrete fragments recovered from the demolition of infrastructure in the Clot neighbourhood of Barcelona. Following the congress, it will not be discarded, as it forms part of an ongoing pilot project. It will form the first module of a retaining wall that will be reused and replicated in a public park currently under construction in the city. 

Barcelona, the epicentre of global architecture 

From 29 June to 2 July, Barcelona is hosting the UIA World Congress of Architects 2026: featuring over 10,000 participants, 250 international speakers, 100 sessions and a 4,000 m² central exhibition at the CCCB and other iconic spaces around the city. 

Following the congress, from 3 to 19 July, the programme continues with a post-congress featuring free-access exhibitions and workshops distributed across key venues in the metropolitan area, including the exhibition of the Spolia prototype. 

The congress, convened by the International Union of Architects—which represents over a million professionals from more than 100 countries—is organised by the CSCAE and the COAC, and brings together renowned architects, researchers and leading figures from various disciplines to reflect on the future of architecture.