Degradation of brick masonry walls in Europe and the Mediterranean: Advantages of a response-based analysis to study climate change

Climate change (CC) has an impact on degradation mechanisms in building envelopes. A climate-based analysis (only using climate variables) or a response-based analysis (based on hygrothermal simulation results) can be performed to assess the CC impact over a large region. Only the latter accounts for building parameters (e.g. material properties, wall composition ...), which is more reliable, though at a high computational cost and not state-of-the-art. It remains unclear whether a climate-based analysis is suitable to study the CC impact on building envelopes. Therefore, we compared a climate-based and response-based analysis by means of 34.560 hygrothermal simulations across Europe and the Mediterranean, including a high number of building parameter variations (i.e. 'cases'). In the north of Europe (Bodo), freeze-thaw damage and wood decay are projected to increase (81% and 68% of the cases, respectively). In the mid-latitudes of Europe (Berlin, Brussels, Milan, and Madrid), there is a decrease in freeze-thaw damage in 66%-78% of the cases. Mould growth and wood decay tend to increase in up to 51% of the cases in Brussels, and decrease in halve of the cases in Madrid. In Cairo, Bouarfa, Valencia, and Athens, the degradation risks remain small. Further, there is a weak Spearman rank correlation (maximum 0.46) between the climate-based and response-based CC impact. The error goes up to 100% when using a climate-based analysis. Moreover, the climate-based analysis is unable to represent the spread of the CC impact between different building parameter variations. The climate-based analysis is only suitable as first assessment.