Towards a net-zero carbon economy: A sustainability performance assessment of innovative prefabricated construction methods for affordable housing in Southern Africa

Recently, efforts to mainstream sustainability principles into affordable housing projects through the adoption of modern methods of construction, like innovative prefabricated construction methods (IPCMs), have been observed. However, limited studies have evaluated the sustainability performance of IPCMs deployed to affordable housing projects in Southern Africa, where the delivery of sustainable affordable housing remains a regional imperative. This study bridges this gap by assessing the sustainability performance and index scores of six IPCM variants implemented on affordable housing projects. The study adopted a two-phased quasi-experimental research design. In the first phase, the technical specification, lifecycle energy and cost and actual performance of these variants under varying conditions pertaining to sustainability were assessed and compared. The Sustainable, Innovative, Affordable Housing (SIAH) framework was adjusted to enhance its utility for computing sustainability index scores using expert opinions. Afterwards, the experts computed the sustainability index score for each case using the adjusted SIAH framework. Subsequently, the Edge App and SimaPro were used to simulate the sustainability performance of these variants under varying conditions. The study's results indicate higher overall sustainability performance of IPCMs compared to conventional methods. Moreover, the research results proved that the monolithic IPCMs were more suitable for net-zero carbon buildings. The study highlights the SIAH framework's usefulness as an assessment tool for determining the sustainability performance of affordable housing projects and for successfully selecting optimum IPCMs to implement towards eliciting such performance. It is expected that this study's results will contribute towards advancing the SIAH agenda in Southern Africa.