Behavior of Brick Masonry Veneers under Wet–Dry Cycles and Varying Differential Air Pressures

Wind-driven rain is a significant contributor to moisture in buildings, posing risks of interior or exterior damage to structures. Climate change is expected to cause increased wind speeds, intensity, and frequency of wind-driven rain events. Although previous research has examined masonry performance under static conditions, the effect of cyclic wind-driven rain events remains unknown. The objective of this study is to understand the effects of the time interval between consecutive wind-driven rain events under standard and severe weather conditions. The study also evaluates the behavior of masonry veneers under various differential air pressures. This research bridges the gap between laboratory-based assessments and real-world environmental exposure scenarios. The methodology of this research included full-scale experiments on clay brick veneers using a rain chamber to simulate various weather conditions. The findings of this research contribute new insights into the moisture resistance of building envelopes under various cyclic-driven rain exposures. The key findings of the study revealed that frequent rain events, regardless of wind speed, resulted in increased water leakage that was not observed in static performance assessments. The study also shows that a minimum drying time interval of 24 to 48 h is needed to reduce water leakage, depending on the differential air pressure. Moreover, the study proposes a more realistic testing approach that captures the cumulative impact of successive rain events. The experimental framework developed in this study can be applied to assess other facade systems under similar climatic conditions. Furthermore, the study indicates that design based on higher wind speeds may lead to conservative results. The observations of this study highlight the importance of considering realistic weather conditions and drying intervals in the design of masonry veneers, supporting the need for performance-based design approaches in moisture-sensitive regions.