Hygrothermal performance of hybrid multi-storey buildings under future climate scenarios

Climate change, energy efficiency, and carbon footprint objectives pose significant challenges to the hygrothermal performance of building structures in climates with extreme temperature variations. To meet long term sustainability targets, buildings designed for a lifespan of up to 100 years must exhibit resilience not only to current climate conditions but also to projected future scenarios. This study evaluated the hygrothermal performance of a hybrid log-concrete multi-storey building, combining the structural strength of concrete with the sustainable, moisture-regulating properties of wood, to address energy efficiency and moisture control challenges in subarctic climates. Onsite measurements were validated using numerical simulations to assess hygrothermal performance of log wall structure under climate change scenarios. Results showed minimal mould growth risk under present conditions, while future climate projections (RCP8.5 for 2080) indicated a maximum mould index of 1.32 near the exterior log surface. These findings highlight the resilience of log-based structures in cold climates and underscore the need for proactive moisture management under warmer, more humid future scenarios. Stable ideal indoor temperatures (averaging 21.56 °C to 22.09 °C) and effective moisture control (with a maximum average moisture excess of 0.89 g/m³) over the measurement period further demonstrate the suitability of hybrid log-concrete buildings for energy-efficient, moisture-regulating construction in cold climates. The study recommends surface treatments that allow vapour diffusion while preserving wood’s hygroscopic qualities to enhance durability in changing climates.