Capturing variability in material intensity of single-family dwellings: A case study of Toronto, Canada

The need to reduce resource use in the built environment is widely recognized, but quantitative understanding of material use in buildings is limited, especially at neighbourhood and city scales. Existing bottom-up material inventories largely rely on typology-based methods, using representative buildings with little quantification of variability in material use. They also typically focus on advancing material replacement or recycling with less attention to reducing material use. This paper quantifies the material intensity of 40 single-family wood framed dwellings in Toronto, Canada. Design and construction drawings from the Toronto Committee of Adjustment and local building codes were used to estimate material quantities for each building. The variability in material use and intensity is explored per building, floor area and number of bedrooms and the largest drivers determined to identify opportunities for building design modifications to meaningfully reduce material intensity. Variability in the quantities of construction materials used within the single-family dwellings studied is large, with coefficients of variation ranging from 13% up to 160%. Concrete basements are the largest driver of material use by mass (mean 56% of total material mass) and building envelope insulation by volume (37%). This paper advances our understanding of the range of material intensities within a single building type in one city and the largest drivers of material use within single-family dwellings. This provides valuable information for including variability in typology approaches to bottom-up urban material intensity and insights for policy/design pathways for reducing material use in single-family dwellings.