Freeze-thaw damage assessment of internally insulated historic brick masonry walls under a changing climate

Preserving the cultural significance of historic buildings while improving their energy efficiency may seem contradictory. For instance, to maintain the original façade of historic buildings it is not possible to add thermal insulation to the exterior walls. Alternative measures such as applying insulation to the wall interior need to be considered. However, such measures are considered one of the most difficult retrofit solutions for historic buildings. Research suggests that introducing internal insulation in historic masonry walls amidst varying climate conditions poses potential challenges in controlling moisture and maintaining the integrity of the masonry structure. It is therefore crucial to conduct a comprehensive assessment of the possible risks linked to moisture-related issues such as freeze-thaw (FT) damage to masonry walls. This study provides recommendations for enhancing the energy efficiency of older historic buildings without compromising their cultural significance and long-term durability by examining methods for internal insulation. The hygrothermal behavior of historical masonry walls was investigated before and after retrofitting in response to historical and future climates. Ottawa was selected as the study location to conduct the analysis. The investigation included various factors such as the local climate conditions, building height/size, as well as brick and insulation material properties. Hygrothermal simulations over a 31-year period were performed to predict the risk of FT damage. This study provides a decision-making procedure for retrofit projects of historic masonry buildings requiring internal insulation and suggests solutions in situations where caution is required. • Freeze-thaw damage risk of historic brick walls with interior insulation was investigated. • Variables include WDR exposure, orientations, brick types, insulation types and thickness. • A decision-making procedure for safely insulating historic brick walls is proposed. • Solutions for safely insulating historic brick walls are possible with proper analysis and caution.