On the site where this social housing for older people now stands, there was a former school in very poor condition and outside current planning regulations, making its preservation impossible. Rather than seeing demolition as a loss, the project turned it into an opportunity: using the materials from the existing building to construct the new one. This strategy, known as urban mining, is based on a simple but powerful idea: resources do not need to come from far away, but can come from the very place where the new building is created. After demolition, almost all the materials were carefully sorted and reused. Concrete and ceramic fragments were incorporated into the foundations and basement walls, while the recovered marès stone was used to produce around 3,000 prefabricated blocks that now form the building’s load-bearing walls. These walls support the cross-laminated timber floor slabs, giving the project both solidity and construction efficiency. The result is a building that reduces waste, reuses local resources and embraces passive design strategies, including thermal mass, natural cross-ventilation, solar gain in winter and solar protection in summer.