Residential building material stocks and component-level circularity: The case of Singapore

The residential built environment plays a crucial role in supporting many human activities. In urban areas however, high-rise residential buildings require significant investment of material resources, which are stacked for a long time over the building's lifetime. Assessing the Material Stock (MS) of buildings has been the focus of several studies for insights into in-use materials and their potential availability as secondary resources. The study of material circularity, or the potential to reuse materials emerging from end-of-life buildings, has so far been mostly limited to metals. This study argues that material stock analysis at individual material or material categories e.g. mineral, or metals, need to be complemented with building component stock estimations to enhance the potential for secondary resource recovery. Based on a bottom-up stock analysis approach, we estimate both the material and component stock of public housing developments in the city-state of Singapore and associated annual in- and out-flows.