Understanding the embodied carbon credentials of modern methods of construction

This study assesses the embodied carbon credentials of modern methods of construction (MMC) by conducting a critical literature review and synthesis of the findings. While several studies have reviewed the broader impacts of MMC, no other study to date has comprehensively reviewed the embodied carbon credentials of this construction typology. Since MMC is not an internationally recognised term, the assessment is inclusive of other terminology used in different parts of the world – e.g. prefabrication, off-site construction and industrialised construction. The study captures 250 separate studies and distils these to a final sample set of 41 studies and a total of 82 case study comparisons. Although a general perception exists that the adoption of MMC results in embodied carbon savings, the evidence to support this claim is not robust. The results from individual case studies range significantly in both direction and magnitude, and, in the absence of a critical review, considerably different conclusions can be drawn. Upon critique and synthesis of the published studies, it is found that the adoption of MMC has no significant positive, or negative, impact on the embodied carbon of a building. Policy relevance MMC have been widely cited as the answer to housing shortages and productivity issues in the construction industry more broadly. They have subsequently attracted political attention and implementation in many regions. Embodied carbon is another topic of continued debate in built environment policy. There is a somewhat hopeful assumption that the adoption of MMC will reduce embodied carbon. But, to date, the evidence to arrive at that assumption has been inconsistent. The literature that compares MMC with traditional construction varies considerably. It is found that there is no broad link between MMC and reduced embodied carbon. Reducing the embodied carbon of buildings requires assessment on a case-by-case basis.