While small-scale lab testing and field monitoring studies have been conducted on mid-rise and tall wood buildings in terms of hygrothermal, indoor thermal conditions, and energy performance (McClung et al. 2014; Wang 2019; Schmidt et al. 2019), to improve building designs and help develop models and best practice guides, more field data is needed. In this sub-project, a comprehensive field performance monitoring of MT buildings in different climatic regions will be carried out to monitor hygrothermal performance of building envelope, indoor environment, and energy consumption. The expected outcomes are (1) field performance data in representative Canadian regions; and (2) design recommendations to achieve durable, energy efficient, healthy and resilient mass timber buildings. The field monitoring data will be used for model validation in other sub-projects, e.g., sub-project T3-1-A.

This project addresses the challenges of drying mass timber structures after severe construction wetting, a common issue in areas with high moisture exposure. As mass timber buildings become more prevalent, efficient moisture management during construction becomes critical. The research will evaluate various drying methods, including electrical/propane heaters and dehumidifiers, to identify the most effective, energy-efficient, and sustainable techniques for use on construction sites. The outcomes aim to speed up construction, reduce costs, lower the carbon footprint, and enhance the durability of mass timber buildings. The project involves an MASc student and will span two years.

In order for mid-rise and taller wood buildings to achieve net-zero energy under projected future climate conditions, their building envelopes must (1) provide optimal thermal resistance in order to reduce heat loss in the Winter and heat gain in the Summer; (2) enhance passive solar heating while providing proper solar control in the Summer; (3) support renewable energy. In this sub-project different archetype buildings located in different Canadian climate zones will be evaluated. The expected outcomes are optimal design solutions that meet both net-zero energy and durability requirements for future climates, while not compromising structural performance. Given the need for design optimization, this sub-project will involve collaborators from Theme 1 (Chui) and Theme 4 (Al-Hussein), both from UAlberta.

This sub-project will evaluate the overheating risks in wood-frame buildings built to the current energy codes and the proposed NZER standard under current and projected future climates. With the increased frequency of “heatwaves” and projected rising temperatures, energy-efficient buildings designed to reduce energy consumption for space heating in Canada may be subject to a risk of overheating in warm seasons (Baba and Ge 2019; Laouadi et al. 2020). The expected outcomes of this sub-project are design and operational strategies, such as natural ventilation, night-time cooling, solar control through passive solar design and dynamic shading, thermal mass, and pre-cooling to reduce overheating risks in wood- frame multi-unit residential buildings, located in different Canadian climate zones.

While most performance issues for mid-rise wood-frame construction related to structural, fire, and energy performances have been addressed, potential water damage due to accidental indoor water leakage has not been investigated in depth and remains a concern for owners and insurance companies (Ni and Popovski 2015; Hodgin 2018). This sub-project will focus on identifying potential sources of indoor water leaks, their impacts, and measures that can be taken to improve the resilience of wood- frame construction against such risks. The expected outcomes are effective moisture management guidelines for dealing with indoor leaks to prevent damage to wood components.

Air-tight energy efficient buildings rely on mechanical ventilation to ensure indoor air quality (IAQ), while higher ventilation rates may be required to deal with emergencies such as COVID-19 (Lewis 2021). Maintaining a safe, healthy, and comfortable indoor environment while limiting energy consumption has become particularly important for all residential buildings (Memmott et al. 2021). This sub-project aims to develop ventilation strategies to achieve optimal IAQ in energy-efficient wood buildings. The expected outcomes are design tools and energy-efficient ventilation design and operational strategies and guidelines for achieving healthy wood buildings.

Deep energy retrofitting of existing buildings has become critically important as a means of reducing energy consumption and carbon emissions from the built environment. It also makes older buildings more comfortable, durable, and climate-resilient. One of the most effective approaches to deep energy retrofitting is exterior retrofitting carried out by adding prefabricated panels to the exterior walls and roof to improve thermal performance. This sub-project will examine the use of light-wood or MT assemblies for exterior energy retrofits. Conventional light-wood-frame panels and innovative wood fibre insulation-based panels will be used for low- and mid-rise wood buildings, while CLT-based assemblies may be applied to non-wood buildings up to 12 storeys. The expected outcomes are a comprehensive strategy and innovative assembly designs with wood-based, low-carbon products for the exterior envelope energy retrofit of existing buildings that has the potential to be scaled up for existing buildings, including non-wood structures. The work will also facilitate and expand the use of innovative bio- products, including wood fibre insulation, in North America. Collaborators from Theme 1 (Erochko) and Theme 2 (Hajiloo) will be part of the project team (all from CarletonU).