Research pick: Our house is not necessarily a very, very green house - "A critical evaluation of the sustainability of building codes and policy when embodied carbon is considered for the construction of three-bedroom houses in UK"

Research in the International Journal of Sustainable Real Estate and Construction Economics draws attention to a neglected element of the UK’s climate strategy: the carbon locked into the materials used to construct new homes.

These embodied carbon emissions arise not from the daily operation of a house but from the extraction, processing, transport and assembly of the materials themselves. Embodied carbon emissions are released before a building is even occupied, they are effectively front-loaded into the atmosphere.

There is therefore a substantial gap in the regulations that must be filled: while energy use within homes is monitored, the emissions embedded in supply chains remain outside the scope of current standards. While policymakers have so far concentrated on cutting the energy required to heat and power homes, the research suggests that material-related emissions may soon outweigh operational ones as the national grid shifts towards renewables and building standards improve energy efficiency.

The study examined the structural frames of a typical three-bedroom house, the most common size built in the UK, using both manual calculation and a digital life cycle assessment tool. The researchers compared three common construction materials: wood, steel and brick. Their analysis found that wooden frames carried the lowest embodied carbon, bricks-and-mortar frames the highest, and steel fell in between. The high carbon cost of steel was attributed largely to the energy-intensive process of smelting ore, while the emissions associated with bricks accumulated through both production and transport.

These findings carry weight beyond the construction site. The UK faces a shortfall of hundreds of thousands of homes each year. Meeting this demand while also honouring commitments to net-zero carbon emissions by 2050 represents a major challenge. Current regulations focus on energy efficiency in use but do not take into account embodied carbon. The absence of such considerations, the researchers warn, risks locking in decades of additional emissions during a period when international climate agreements call for steep reductions.

King, H., Rawson, R. and Okere, U. (2024) ‘A critical evaluation of the sustainability of building codes and policy when embodied carbon is considered for the construction of three-bedroom houses in UK’, Int. J. Sustainable Real Estate and Construction Economics, Vol. 3, No. 1, pp.63–81.