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Executive Summary

Recent analyses of climate data, as well as climate modelling, indicate that the Canadian climate is changing and will continue to do so as part of the global phenomenon of anthropogenic climate change. These changes have both acute and long-term effects on many aspects of the Canadian economy, including our built infrastructure. As part of a review of its collection of standards to assess the need to adapt them to climate change, CSA Group identified several standards as high, moderate, or low priority for adaptation; the current report represents a portion of the efforts arising from the review.

This report provides recommendations for the adaptation of masonry standards to the effects of climate change. Included is a detailed review of the literature related to the effects of climate and climate change on masonry materials and design, as well as a discussion of how this information may be used to strengthen current standards. The report was informed, in part, through consultation with key experts and stakeholders in the masonry industry.

The following masonry standards are discussed in this report:

• CSA A82:14 (R2018), Fired masonry brick made from clay or shale
• CSA A165 Series-14 (R2019), CSA Standards on concrete masonry units
• CAN/CSA-A179-14 (R2019), Mortar and grout for unit masonry
• CSA A370:14 (R2018), Connectors for masonry
• CAN/CSA-A371-14 (R2019), Masonry construction for buildings
• CSA S304-14 (R2019), Design of masonry structures

The CSA A370:14 (R2018), Connectors for masonry standard was one of the standards identified by CSA Group as a high priority for climate change adaptation, mostly since it includes climate data (a table of annual Driving Rain Index [aDRI] values) for various locations in Canada. Other masonry standards were identified as moderate or low priority for adaptation; however, interesting insights may be gleaned from the literature on how climate effects may be accounted for in future iterations of these standards. These include information related to adapting masonry to the changing climate itself, as well as to changes in practices, policy, and regulations aimed at mitigating future carbon emissions and climate change.

The main recommendations of the report pertain to the criteria used to determine the minimum corrosion protection requirements for masonry ties. As there are many indications of widespread changes in the aDRI across Canada over the past decades, and projections for further changes in the future, these changes should be accounted for. Alternate criteria, such as the use of the National Building Code of Canada’s Moisture Index (MI) may also be considered. Other recommendations include the addition of guidance in the standards on the application of sophisticated testing and analysis methods to quantify the durability of masonry connectors, masonry units, as well as mortar and grout.

Research needs identified in this report include the need for new research to determine regional trends in changes to the severity of freeze-thaw cycling, quantifying the relation between climatic factors (e.g., aDRI or MI) on the corrosion rate of masonry connectors, and quantifying the phenomenon of rain penetration through masonry veneer cracks.

Other considerations discussed in this report arose due to ongoing efforts to mitigate future climate change by reducing CO2 emissions and energy usage. The design of buildings must now account for the energy and CO2 emissions embodied within the materials and construction processes as well as the energy efficiency of the finished structure. Many key industry stakeholders identified challenges faced in quantifying the energy benefits and trade-offs of masonry construction, and indicated that fair comparison with other construction materials is often difficult. As material science and building science continue to progress and evolve, there is a growing need for standardized metrics and methods for quantifying dynamic thermal performance, thermal bridging, embodied energy, and long-term durability of building materials.