A critical evaluation of the sustainability of building codes and policy when embodied carbon is considered for the construction of three-bedroom houses in the United Kingdom

UK house building focuses on operational emissions from newly built houses, this paper aims to evaluate how policy can be changed to help reduce Scope 3 emissions within the house building sector. Greenhouse Gas (GHG) emissions result in global warming and are caused by three different Scopes (1, 2, and 3) across an organisation’s products, services, and activities. Scope 1 relates to direct GHG emissions from a business such as fuel used for transportation, release of refrigerants from Heating, Ventilation and Air Conditioning units and fuels used for heating. Scope 2 relates to indirect energy use such as electricity generated from power generation or steam generated offsite such as from a District Heating Network. Scope 3 are regarded as all indirect emissions from the organisations supply and value chain. Newly constructed houses release GHG emissions for Scopes 1, 2 and 3. In the UK, the Government is introducing standards to reduce operational emissions in the form of building codes and policy documents such as The Future Homes Standard. However, considerable emissions are generated from Scope 3, the cradle-to-gate Life Cycle Assessment phase. This research therefore investigates the significance of embodied carbon within structural frames of new houses and its policy implications. The structural frame of a three-bedroom house was used to calculate the embodied carbon of building materials. Results from One Click LCA, an automated lifecycle tool that can be used to calculate the Life Cycle Assessment GHG emissions, were compared to manually calculated values. The annual average number of new houses was calculated providing total embodied carbon for each material. Results demonstrate that houses generate significant Scope 3 emissions because of the significant amount of materials that are used to build the houses. Since these emissions relate to the materials of house, they are therefore related to Scope 3 as they are supply chain GHG emissions. Wooden frames had the lowest embodied carbon when compared to houses made with steel frames and bricks and mortar. Policies should address embodied carbon to reduce emissions from new build houses. Full Life Cycle Assessment analysis within building standards, replacing bricks and mortar with wooden or steel frames, and GHG intensity scoring are recommended. This would impact society by reducing the significant amount of embodied carbon emissions from the materials of newly built houses and be a significant contribution to staying within 1.5°C and preventing extreme climatic conditions.