Standards and Application Challenges in Prefabricated Roofing and Wall Assemblies

Abstract Prefabricated construction has gained traction in North America as a sustainable solution for addressing the needs of a growing population. The time and cost involved in traditional construction methods further challenge the expansion of affordable housing. To address these shortages, Canada is working to accelerate the building process. Contemporary approaches such as prefabricated construction have emerged as practical solutions to meet current housing needs more efficiently and affordably. Prefabricated construction, a subset of off-site construction, involves assembling building components manufactured off-site and integrating them with the main structure on-site to complete the building process. In Canada, roof and wall assemblies represent the primary components of low-rise wood-frame construction. Prefabricated roof and wall products are required to comply with performance criteria established in codes and standards. However, their design details frequently diverge from those of conventional assemblies. In some cases, existing codes and standards are insufficient to ensure all required performance levels or fail to address certain aspects altogether. Accordingly, this paper aims to (1) define different types of prefabricated roofing and wall assemblies; (2) provide a comprehensive review of existing North American and international codes and standards, with a focus on their application to prefabricated construction in Canada; and (3) examine the challenges and technical barriers to broader market adoption, drawing on real-case scenarios. The review indicated knowledge gaps in current codes and standards. Additional consideration is needed to ensure the adequacy of all performance aspects, including hygrothermal, structural, and durability, for prefabricated building envelope systems. Specific challenges observed from the case studies revealed issues related to moisture leakage and moisture management, as well as design and installation discontinuities.