Mapping the climate impact of construction processes: a case study from Denmark

Construction processes comprise a significant proportion of a building’s embodied carbon and resource consumption. Life cycle assessments (LCAs) allow for calculating impacts from embedded materials throughout a building’s life cycle. However, research on life cycle modules related to transport (A4) and the construction installation process (A5) is limited. Current studies suggest that construction processes contribute between 5 and 18.5% of the climate impact but lack consistent methodological approaches and exhibit variable background data, hindering clear comparisons. This study aims to establish a basis for comparison by conducting a comprehensive LCA for a multifamily residential from Denmark, including the construction phases. Site-specific data for the case study, including transportation details, grid-based energy metering, and hauling tickets, were directly provided by the building contractor, ensuring the accuracy and completeness of data collection. The study shows that construction processes contribute 12.3% to the studied residential building’s whole-life carbon emissions (WLC). Approximately 62.5% of the total carbon emissions are attributable to upfront emissions and, thus, are emitted before the building’s occupancy, indicating significant potential for immediate emission mitigation measures. The study’s insights into carbon emissions related to construction activities highlight transportation and waste management as substantial contributors. This offers pathways for emission monitoring and facilitates a framework for further exploration to mitigate carbon emissions during the construction phase.