Mapping material use and embodied carbon in UK construction

Abstract

The embodied carbon of UK construction is estimated at 43 MtCO2e, with 80% from material production and on-site activities. This value has previously been calculated using a multi-region input-output model which models consumption-based emissions using a top-down approach. However, no detailed information exists on the specific material inputs and their related embodied emissions. In this paper, for the first time, uses a bottom-up approach to give much more detailed breakdown of estimates of material use and carbon emissions in UK construction. Ten residential and five non-residential building typologies were analysed and scaled to cover the UK. The scope includes steel, cement & concrete, clay products, timber, glass, plastic, aluminium, stone and gypsum products. We find that 84 Mt of materials were used to deliver the shell and core of buildings and infrastructure, with an embodied carbon of almost 22 MtCO2e. Approximately 14.5 Mt and almost 3.6 MtCO2e (steel and concrete only) was used for external works and refurbishments. Half of the total embodied carbon is from concrete, which is mainly used in foundations, ground floor slabs and upper floor slabs in buildings, as well as infrastructure. For equivalent materials, the dierences between bottom-up and top-down analysis is less than 15% for cement and concrete, 20% for steel and bricks (top-down analysis provided lower estimations). This analysis allows identification of the aspects of construction with the highest related embodied carbon emissions, and finds the strategies for their minimisation.