High performance building envelope for climate resilient buildings

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The effectiveness of the building envelope to resist climatic loads determines the performance and durability of the building, its energy consumption, and the extent to which its net-zero/plus energy status can be achieved. Moisture intrusion by wind-driven rain (WDR) and runoffs is the major source of moisture causing many building envelope failures and often results in costly repairs, such as the case of leaky condominium in Vancouver area. With a changing climate, higher temperature and solar radiation, stronger wind and higher amount of precipitation, more frequent storms and extreme weather events are expected. Higher WDR amount on façade caused by climate change and potentially increased moisture damage risks would be expected. Buildings built and retrofitted today need to be resilient to climate change. The focus of this research is to 1) advance the understanding of WDR and its impact on building envelopes under future climates; 2) develop models, design tools and guidelines for designing building envelopes suitable for their intended microclimate and 3) develop climate resilient building envelope solutions for retrofits. The proposed research built upon the applicant's successful previous research on "Wind-driven rain and its impact on building envelopes", which has generated unique field WDR data on a large number of buildings in different regions of Canada, established empirical correlations for quantifying the effectiveness of overhang and a validated CFD WDR model. These research efforts have led to a set of recommendations on ISO provisions for more accurate quantification of WDR on façade. The applicant has also developed a stochastic modeling approach that takes into account a variety of uncertainties for a better assessment of moisture risks of building envelope. These research outcomes are important in preventing premature building envelope failures, impacting on building codes and standards related to building envelope durability, and addressing climate change. The proposed research program will involve a balance between modeling, laboratory testing and field measurements. The methodology will include: i) laboratory and field measurements of façade runoff combined with modeling to better predict the WDR load on façade; ii) development of methodology for better assessment of moisture risks of building envelopes under future climates, iii) development of design tools and guidelines for climate resilient building envelope systems; and iv) development of cost effective and pre-engineered building envelope systems that are energy generating and durable for retrofits. The proposed research program will support Canadian government's effort in integrating climate resiliency into building design, codes and guides, contribute to Canada's national objectives for the reduction of the GHG emission, and train the next generation of building engineers and professionals in effectively dealing with climate related issues.