Parts of the building envelope that frequently receive high amounts of rain are usually exposed to a higher risk of deterioration due to moisture. Determination of such locations can thus help with the assessment of moisture-induced damage risks. This study performs computational fluid dynamics (CFD) simulations of wind-driven rain (WDR) on the Parliament buildings in Ottawa, Canada. Long-term time-varying wetting load due to WDR and potential evaporation are considered according to several years of meteorological data, and this cumulative assessment is proposed as a fast method to identify critical locations and periods. The results show that, on the Center Block of the Parliament buildings, the façades of lower towers facing east are the most exposed to WDR, together with the corners of the main tower. Periods of high WDR wetting load larger than the potential evaporation are observed, indicating that deposited rain may lead to moisture accumulation in the envelope. During these critical periods of up to several months, air temperature may repeatedly drop below freezing point, which poses a risk of freeze–thaw damage. First assessment on future freeze–thaw damage risks indicates an increase in such risks at moderate increases in temperature, but a lower risk is found for larger increases in temperature.

Due to climate change, considering future rain event patterns and increased average temperatures, wind-driven rain exposure of buildings can increase. In order to assess the future damage risk related to moisture, it is essential to take the future wind-driven rain load into account. Computational fluid dynamics simulations of wind-driven rain are performed on a historical building located in Victoria, BC, Canada using the current and future weather data. The results show an increased wind-driven rain exposure of the building by up to 20%, especially in façade regions which are already exposed to a higher amount of rain.

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Accurate estimation of wind-driven rain (WDR) load on building facades is of paramount importance for the assessment of moisture-induced damage risks. Computational fluid dynamics (CFD) simulations of WDR are performed for the Parliament Buildings in Ottawa, Canada. Combined with a statistical analysis of the long-term local meteorological conditions, zones of facades receiving the highest amount of WDR are determined. Then, for critical locations on the facade, the Climatic Index is used as a metric, taking into account the total wetting load and total drying potential, in order to identify the façade locations and periods that show high risk of moisture damage.