Optimising the balance between flexibility and structural mass for lower short- and long-term embodied carbon emissions in mass housing

The building construction industry is one of the largest contributors to global greenhouse gas emissions. One solution to reduce the industry's carbon footprint is to design structures efficiently, thus using less structural mass. However, over-designing is a fundamental aspect of flexibility; a building's capacity to make physical changes in the future – which is key for domestic buildings in particular. It is therefore important to strike a balance between structural efficiency and high flexibility, to limit both short- and long-term embodied carbon emissions. This balance was investigated using a mass housing case study, creating a series of design iterations to explore the trade-off between flexibility and structural mass. An optimum solution illustrated that this case study can be redesigned to have double the flexibility, lower structural mass, and less carbon-intensive materials. Therefore, this research concluded that it is possible to significantly reduce the short-term embodied carbon emissions of this housing design, whilst simultaneously reducing long-term emissions too. Although these findings might be specific to this case study, the duplicate nature of mass housing means that the carbon savings of this one housing design can be multiplied many times across a whole development. Applying this research to other mass housing designs could significantly reduce the embodied carbon of future developments and improve the carbon footprint of the building construction industry.