TransFIRe researchers have co-authored a paper in which they quantified and benchmarked the material use and embodied carbon to the deliver the ‘core and shell’ of typical residential and non-residential buildings.

In this paper embodied carbon emissions, equivalent to greenhouse gas emissions (GHG), are released during the production of materials and construction processes rather than when it is in use. They are an essential measurement to deliver carbon neutral buildings. With the government’s 2050 net-zero deadline approaching and the pressure to decarbonise increasing, it is vital that ways of minimising levels of embodied carbon are tackled.

The detailed bottom-up approach taken by the researchers showed that, compared to the top-down analysis, the embodied carbon emissions were underestimated by up to 20%.

Combining their detailed bottom-up model with top-down analysis and other material consumption data, the researchers found that in 2018 (the year in which the most recent available high-level data was available to calibrate the model and comparable in terms of UK construction to 2022), 100 Mt of materials were used with an embodied carbon of 25 Mt CO2e, half of which came from concrete.

 

 

Their methods have also allowed for the identification of areas of high potential for decarbonisation and, as the model used covers both common building typologies and technologies, it can be used internationally, not just the UK.

Avoiding the demolition of buildings would save 30% of the total embodied carbon alone.  In addition, conversion for flats uses nearly half as much carbon and material that creating new medium and high-rise residential buildings.

In fact, if the entire demand for residential properties was covered by converting non-domestic buildings and offices into dwellings, then 34% of the total construction embodied carbon emissions could be saved.

The study found that medium and high-rise residential buildings and mid-terrace houses produce the lowest amounts of embodied carbon, therefore material and carbon could be saved by building multi-story buildings and longer rows of terraced houses with a greater proportion of mid-terraces.

In addition, 20% of embodied carbon could be saved by switching to the most material and carbon efficient technology options, for example, using timber frames or steel composite decking for construction.

Unfortunately, circular economy principles are not largely used within construction industry currently and only steel has a high recycling rate.  It is therefore critical to find ways of reusing materials as a carbon mitigation solution for construction.


Mapping material use and embodied carbon in UK construction
Resources, Conservation and Recycling
Volume 197, October 2023, 107056

https://doi.org/10.1016/j.resconrec.2023.107056

Michał P. Drewniok, José Manuel Cruz Azevedo, Cyrille F. Dunant, Julian M. Allwood, Jonathan M. Cullen, Tim Ibell, Will Hawkins.