Extract

Residential buildings account for 17% of global greenhouse gas (GHG) emissions. With detached housing accounting for over 70% of all of Australia’s residential dwellings, and a projected doubling of population in the next 40 years, these houses represent a significant opportunity for GHG emissions reduction. Prefabrication can improve the environmental performance of buildings through lower resource input, reduction in waste and improved quality. However, little research exists on whether it reduces embodied GHG emissions, an increasingly significant proportion of a building’s life cycle GHG emissions. The aim of this study was to compare the embodied GHG emissions associated with the construction of detached residential housing in Australia using panelised prefabricated external wall systems. This study used a Path Exchange hybrid life cycle inventory approach to quantify the construction-related embodied GHG emissions of a typical detached house with three external wall assembly variations: cross laminated timber (CLT), structural insulated panels (SIPs) and prefabricated timber framed panels. Compared to conventional brick veneer construction, the prefabricated timber framed panel was the only one that lowered embodied GHG emissions (by 7%). The SIPs resulted in the highest embodied GHG emissions for the house (6% higher than the brick veneer option). The use of prefabrication may not always reduce GHG emissions associated with house construction. In reducing the initial embodied GHG emissions, while the construction process accounts for around 30% of these emissions, the key focus should be on selecting materials with low GHG emissions intensity.

Keywords: Panelised prefabrication; life cycle assessment; embodied greenhouse gas emissions; residential buildings.

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