Microclimate modelling and hygrothermal investigation of freeze-thaw degradation under future climate scenarios

Abstract

Future climate scenarios lead to changes in the boundary conditions impacting the service life of building envelopes. This may increase or decrease the risk of degradation caused by e.g., freezing and thawing on brick façades. In this study, the risk of degradation based on individual years is compared for different moisture reference year (MRY) selection methods. Furthermore, two new MRY indices, based on the Frost Decay Exposure Index (FDEI), are proposed to assess future climate scenarios. A brick façade in Gothenburg, Sweden, is used as a case study to investigate the microclimate caused by façade orientation and solar radiation on three different parts of the façade. The risk of damage is compared for climate scenarios A1B and A2 from 1961 to 2100. The microclimate of the façade is modelled to obtain boundary conditions for each part instead of using MRYs as uniform boundary conditions for the whole building. The study demonstrates a 67% difference in risk of degradation between the different parts of the façade. Furthermore, the risk of freeze-thaw degradation reduces in the future. Finally, it is indicated that the basic FDEI index is better at evaluating the severity of exposure compared to its derivatives.