Projected changes of wind-driven rain and moisture load in wall assemblies across Canada

Abstract

The changing climate is affecting many aspects of the built environment. In respect to the wall assemblies of buildings, any change in the moisture load to the wall would influence its long-term moisture performance. Given that Wind-Driven Rain (WDR) is the primary source of the moisture load to the wall and that this load may also change as a result of changes to the climate in the future, it is expected then, that such changes will subsequently affect the moisture performance of wall assemblies. In this study, changes in moisture load of a vinyl-clad and a brick veneer-clad wall assemblies, located in 11 selected Canadian cities, subjected to climate data for two future projected climate scenarios, 2.0 °C (2034–2064) and 3.5 °C (2062–2092), as generated from the Canadian Regional Climate Model (CanRCM4), were assessed. Climatic parameters such as, WDR and Driving Rain Wind Pressure (DRWP), as well as their Intensity-Duration-Frequency (IDF) curves were analyzed and produced to determine boundary conditions for watertightness testing. The two analyzed wall assemblies were thereafter subjected to such tests, and the results of which were used to establish a two-step approach to estimate the moisture loads in these two wall assembly types based on hourly WDR load and hourly DRWP. Moisture loads of each wall assembly type during future projected climate scenarios were compared to those of the historical baseline periods. Increase in moisture load to both wall assembly types were found for most of cities analyzed in this study.