Material stocks and embodied carbon in UK buildings: An archetype-based, bottom-up, GIS approach

Decarbonizing construction through a circular economy requires an in-depth understanding of the materials stocked within, and flows into, between, and beyond, the global built environment. Archetype-based bottom-up material stock analysis (MSA) is increasingly used to estimate the quantity, location, and embodied carbon of different construction materials within existing buildings. European MSA studies typically employ archetypes based on building use (e.g., residential/non-residential) and/or age (e.g., historic/modern), potentially missing significant variation in material composition across different construction types. Such work also generally focuses on residential buildings and derives aggregated and/or synthetic material intensities (MIs), with non-residential buildings in the United Kingdom rarely being considered through real-world design data. This paper investigates the suitability of different archetyping approaches in the bottom-up estimation of material stocks and embodied carbon in UK buildings. Concrete is revealed to consistently contribute the majority of material mass irrespective of use or construction type, with steel consistently representing a majority of superstructural embodied carbon. Despite the relative agreement between overall structural MIs for use- and construction-based archetypes, varying material and sub-/superstructural composition introduces increased heterogeneity in individual-material and sub-building MIs when considering building construction type. Mapping of use- and construction-based MIs to the building stock level is shown to be inhibited by the infrequent specification of construction type within the utilized inventory. This gives rise to a novel, parallel use and/or construction archetyping approach, reiterating the need for the inclusion of building construction types within both MSA archetyping approaches and national building inventories.