10:30 am - 11:50 am | Room: Pretium Room | Session Chair: Andrea Mucciarone

Hygrothermal Performance Evaluation

Assessing Impacts Of Thermal Upgrades On Mass Masonry Walls: A Tool Kit For The Hygrothermal Analyst

Load-bearing mass-masonry buildings are prevalent on the Canadian landscape, many of them carrying heritage designations. From churches to government buildings, there are still many of these buildings that have yet to be upgraded to modern standards. With Canada’s commitment to net-zero emissions by 2050 and the ambitious climate target of 40-45% emissions reductions by 2030, the drive to upgrade is becoming more prevalent and more urgent. 

Preserving the heritage fabric of these buildings without altering the outward appearance or reducing the long-term durability of the masonry has its challenges. However, insulating exterior load-bearing masonry walls carries the risk of elevating moisture levels by reducing outboard temperatures, resulting in reduced drying potential. Wetter, colder conditions mean an increased risk of corrosion potential or decay of embedded structural steel or timber and, in our Canadian cold climate, greater risk for freeze-thaw (F-T) deterioration of the masonry. 

How do we assess whether a mass masonry building is a good candidate for thermal upgrades? A key piece is understanding the hygrothermal performance of the building: the dynamic movement of heat, air, and moisture within the assembly. Hygrothermal modelling software, is an excellent tool for this. However, it should not be the only part in the process. 

Masonry material properties; brick, stone, and mortar; can range widely from region to region. Even stone masonry units from the same quarry can have wildly varying properties. As such, using generic material properties from a software database will not provide accurate performance predictions for a specific building. When undertaking a hygrothermal analysis of an existing mass masonry building, there are several pre-modelling steps that can be taken, including interior and exterior visual reviews and material testing of site masonry that can improve the accuracy of the model outputs and the level of confidence in the predicted performance.

This paper will explore in depth, the parts of the hygrothermal analysis process that occur before the modelling; visual reviews, exploratory openings, material testing, monitoring; that combined, can help improve the modelling accuracy, inform design designs, and predict impacts of thermal upgrades on long term performance.

Janette Meyrick, WSP

Janette works with the WSP Building Science Facades team in Ottawa, where she specializes in thermal analysis and hygrothermal monitoring programs for heritage masonry buildings. She is the manager of WSP’s national Centre of Excellence for Building Physics and Modelling. A graduate of the Sustainable Building Design and Construction program at Fleming College, she holds a certificate in Building Science from the University of Toronto, and an Applied Science degree, specializing in Building Science. She is a designated Building Science Specialist (BSS).

Cameron Wynn, WSP

Cameron works with the WSP Building Sciences Facade and Restoration team in Hamilton as a Project Manager. Cameron’s specialties and interests are cladding restoration and hygrothermal analysis of existing structures. Cameron is the manager of WSP’s National Centre of Excellence for Cladding Restoration and Evaluation and also a member of the Building Physics and Modelling division. Cameron received his B.Eng at McMaster University and M.Eng at the University of Toronto and is currently pursuing a P.Eng designation.