Ziheng Song

Quantifying the implications of poor installation practices in solid wall insulation retrofits

The UK's existing solid-wall homes significantly contribute to the nation's climate, economic, and social challenges. While retrofitting these homes with solid wall insulation (SWI) offers significant potential to improve their performance, poor installation practices during these retrofits can result in unintended consequences, such as moisture issues and energy performance gaps, which can undermine the effectiveness of the retrofits. Despite ongoing efforts to improve installation quality, poor installation practices remain prevalent in the industry. Therefore, it is crucial to ensure that retrofit designs are robust in delivering the desired performance, even when these practices occur.

The scenario-based performance robustness assessment (SPRA) approach is a potential method for evaluating the robustness of retrofit designs against poor installation practices. However, it has limitations, particularly in its reliance on the direct quantification method to measure the impacts of these practices on design performance, which can lead to oversimplified results from assuming linear, one-to-one causal relationships between these practices and their unintended consequences. To address these limitations, this research proposes the scenario-based impact assessment (SBIA) methodology as an alternative approach for assessing the impacts of poor installation practices. A case study of a pre-1919 detached solid wall home demonstrated the effectiveness of the SBIA methodology in improving the efficiency of the existing SPRA approach. However, further research is needed to refine the methodology, particularly in its scenario attribution process, and to test its effectiveness in enhancing the accuracy of the SPRA approach.