Future moisture loads for building facades in Sweden: Climate change and wind-driven rain

This work investigates the prospective impacts of climate change on wind-driven rain (WDR) and walls through simulating the hygrothermal performance of rain screen of common vertical wall constructions for the climatic conditions of Gothenburg in Sweden. While a substantial amount of work has been done on the impact of climate change on the thermal performance of buildings, this paper studies its impact - through changes in rain, wind and other climatic parameters - on the amount of water which penetrates the outmost layer of ventilated façades. Importance of three uncertainty factors of the climate data are investigated: uncertainties from global climate models, emissions scenarios and spatial resolutions. Consistency of the results is examined by modelling walls with different materials and sizes, as well as using two mathematical approaches for WDR modelling. Sensitivity of the wall simulations to the wind data is assessed by using synthetic climate with sole wind data. According to the results, higher amounts of moisture will accumulate in walls in the future; climate uncertainties can cause variations up to 13% in the calculated 30-year average of water content and 28% in its standard deviation. Using sole wind data can augment uncertainties with up to 10% in WDR calculations, however it is possible to neglect changes in future wind data.