Informal and self-built housing developments worldwide are expanding rapidly, often following incremental construction phases that drive substantial resource demands and emissions as communities consolidate. In Lima, Peru, informal settlements exemplify this trend, revealing significant environmental impacts as progressive construction intensifies urban growth. Informal housing construction in Lima progresses through four key stages: Inception, Development, Completion, and Consolidation, each characterized by material additions and upgrades that increase embodied environmental impacts over time and across all life cycle phases. A Life Cycle Assessment (LCA) was applied to evaluate total greenhouse gas (GHG) emissions, water use, and fossil energy consumption across these four building consolidation stages. Additionally, three end-of-life scenarios—landfilling, recycling, and selective ...

As urbanization continues to surge, building materials are poised to become a dominant contributor to global emissions. Traditionally, the building sector has focused on mitigating “operational carbon” linked to a building's day-to-day energy needs, such as heating, cooling, lighting, and equipment usage. However, there has been a paucity of studies on the environmental impacts associated with building materials across a building life cycle. This paper addresses this gap by conducting a life cycle assessment of housing stocks in two diverse case studies: Montreal (Canada) and Lima (Peru). These cities offer a North/South perspective, highlighting the challenges, opportunities, and potential solutions for decarbonizing the housing sector. The study investigates the potential of circular strategies and investigates three scenarios: selective deconstruction (allowing for reuse and recyc...