A Sustainable Low-Cost Timber Retrofit Design for Improving Structural and Energy Performance of Existing Masonry Buildings: Preliminary Results

Unreinforced masonry (URM) buildings constitute the majority of existing buildings in Canada, including residential, governmental, and heritage structures. Most of these were built before the application of contemporary building guidelines and design codes, which suggests that many existing URM buildings do not necessarily have adequate seismic resistance, even in low-intensity earthquakes. Considering the progressive material deterioration over many decades and lack of maintenance frequently seen in old buildings, seismic retrofitting is necessary for continued occupancy of many structures. Moreover, the existing URM buildings were not originally designed to meet today’s energy performance criterion, which makes them less energy efficient and poses a heavy economic burden on homeowners and tenants who often have limited financial resources. To this end, a new multi-component research project has been launched to develop and test low-cost strategies for retrofit based on engineered timber. These systems are meant to enhance both the structural and thermal performance of ageing URM buildings in order to extend their working life. The strategy studied here comprises a structural layer made of plywood panels with cross-brace frames anchored to URM walls, as well as an energy layer comprised of bio-based thermal insulation. In this paper, preliminary results from ongoing full-scale structural and thermal experimental testing are presented alongside numerical modelling simulations that have guided the proposed design.