Building the Circular Future: Insights from the Castelló Library Demolition

The demolition phase of the Castelló Municipal Library marked a key milestone in Spanish Demo site. Despite the logistical challenges posed by the narrow pedestrian street and limited storage space, the operation was executed successfully, ensuring rigorous control of waste flows, traceability, and valorization by professional local recyclers. The process achieved a 97.6% material recovery rate and maintained very low waste mixing (5.74%), confirming the efficiency of selective deconstruction protocols.

The demolition generated over 700 tonnes of waste , which 50% was concrete and smaller quantities of wood, metals, and plastics, all of which were properly segregated and traced through verified treatment contracts and exhaustive traceability. The on-site implementation of best practices, such as defined collection zones, controlled access, and material purity checks, reflects the project's commitment to circularity, transparency, and environmental performance.

This phase directly contributes to the DeCO2 project transforming a traditional demolition into a data-driven circular process. The digital recording of material flows will be able to feed the BIM-based digital twin, allowing integration of environmental performance indicators and filling the gaps the creation of material passports usually gets. Furthermore, it established the base for the creation of a regional circular innovation cluster in Castellón, linking demolition, recycling, and design actors into a collaborative value chain, ensuring sustainability not only by design but also to the end of the cycle in a digital and verifiable way.

Through this demonstration, the Castelló Library renovation sets an example of how buildings can lead the transition towards low-carbon, resource-efficient renovation models. The demolition phase has not only minimized waste but has also produced quantifiable data and operational learnings that will accelerate circular construction practices regionally and across the DeCO2 project ecosystem.