Effects of temperature and humidity fluctuations on the durability and energy-saving performance of compressed-wood layered structures

This study aimed to evaluate the durability and energy-saving performance of wood compression layered structural materials (WCLS) prepared from Japanese cedar under fluctuating temperature and humidity conditions, and to assess whether deteriorated WCLS retain their insulation function suitable for interior building applications. Specimens were subjected to three weathering regimes (CH, QUV, SKY) and characterised for density, dimensional stability, mechanical properties, glass transition behaviour, and thermal performance. After weathering, WCLS exhibited reductions in density and mass; the volumetric swelling coefficient and water absorption per cent (WAP) decreased, and the equilibrium moisture content declined. However, the anti-swelling efficiency of WCLS decreased by 33–62%, and the moisture-excluding efficiency (MEE) dropped by 13–63%, indicating that part of the initial dimensional-stability and moisture-exclusion benefits diminished after weathering. Both the modulus of rupture (MOR) and modulus of elasticity (MOE) were significantly affected, and the glass transition temperature (Tg) of WCLS shifted to lower temperatures with increasing weathering duration. Under temperature adjustment at high and low relative humidity, the thermal conductivity of weathered WCLS increased by 7–21% and electricity energy consumption increased by 1–21%, although these values remained lower than those of JC (14–36%).