Mass Timber in High-Rise Buildings: Modular Design and Construction; Permitting and Contracting Issues


  • Dalia H. Dorrah Department of Civil Engineering, University of Toronto
  • Tamer E. El-Diraby Department of Civil Engineering, University of Toronto



Due to the inherent inefficiencies in conventional approaches followed in the construction industry and the global demand for lean and sustainable construction techniques, modular construction has witnessed a resurge especially in high-rise buildings. As such, much efforts have been put in studying the use of mass timber for the main structure of high-rise buildings in order to ensure more sustainable developments with high levels of adaptability. In this regard, previous research efforts have primarily focused on the added benefits of mass timber, its structural design and performance, and associated safety requirements. However, owing to the novelty in combining modular processes with timber materials and associated lack of data, several regulatory barriers and contractual issues still exist. To mitigate these issues, this paper studies the specifics of permit approvals and contracting issues in timber high-rise modular buildings. The objective is to develop a comprehensive up-to-date review and analysis of the relevant practices and to conduct interviews with industry experts to analyze their concerns, given the insufficient number of guides and building codes that dealt with these issues. Hence, our study investigates the process of obtaining permit approvals from local jurisdictions in Ontario in addition to the requirements for submission of additional documentation, engineering analysis, and testing. Moreover, it analyzes the initial stage of contractual agreement of stakeholders under the uncertainties imposed on these buildings and evaluates the suitability of Integrated Project Delivery (IPD) contracting method. Presenting detailed analysis of the initial planning stages for timber high-rise modular buildings can in turn suggest the best practices to be taken into consideration for the successful implementation of these buildings under the current building code.