Assessing material flow and housing stock using representative archetypes and sustainability indicators

Building decarbonization and environmental regeneration represent critical global challenges. Conceptualizing buildings as material banks offers opportunities to enhance carbon savings and reduce construction waste. In developing countries, the urban mining potential remains underexplored, particularly within existing housing stocks. This study addresses this gap by evaluating the sustainability performance of a representative subset of the Chilean housing stock through key sustainability indicators. Seventeen housing typologies were examined using a bottom-up material stock approach, encompassing approximately one million dwellings. The findings suggest that timber-based housing typologies exhibit greater sustainability, primarily due to their higher biogenic material content and the reduced presence of non-biogenic materials with low recovery potential. The Weighted Average Housing (WAH) model showed a material inflow of 926 kg/m² (including substructure), with biogenic materials accounting for only 4.8 % and non-biogenic material for 95.2 %, resulting in a low Percentage of Material Circularity (PMC) of 4.2 %. High levels of Embodied Energy (EE) and Embodied Carbon (EC) were observed in the WAH, reaching 10.9 GJ/m² and 623 kgCO₂e/m², respectively, predominantly attributed to the widespread use of concrete. The Urban Mining Potential (UMP) of the assessed housing stock was estimated at 57.2 Mt, equating to 38.3 MtCO₂e of embodied carbon, with an actual recovery potential of only 1.9 Mt. These findings highlight the need to accelerate the use of renewable construction materials such as timber and to foster the development of secondary raw material markets for mineral-based components, particularly concrete and masonry. Additionally, no statistically significant correlation was found between construction cost and environmental performance (PMC, EE, EC), suggesting that more expensive housing typologies do not inherently yield improved environmental outcomes. This study offers relevant insights for built environment professionals and policymakers, identifying key opportunities to enhance circularity and material recovery by leveraging the latent potential embedded within the existing housing stock.