Numerical investigations of dynamic moisture response to the climates inside wooden components in timber buildings and its potential threats

Chinese historical timber buildings are famous for their exquisite craftsmanship. In China, there are various climates with significant fluctuations throughout the year. As some buildings are designed with an open style, many wooden components are exposed to environments with drastic changes in humidity, and the moisture content inside the wood may fluctuate significantly with the changing environment. To protect these architectural heritages from damage, here, numerical simulations were conducted to evaluate the effect of periodic climate conditions on moisture transfer inside wooden components. Five representative cities in China were chosen for comparison, and the long-term variations and dynamic responses of moisture content to periodic climate conditions were investigated. The results show that the moisture content inside the wood varies from 5% to 20% across different cities and months. The plaster layer, made from a mixture of lime, hemp, animal blood, and tung oil, serves as a waterproof coating to prevent significant moisture gradients within the wood. It also reveals that the dynamic moisture response to the climate may pose threats to historical buildings. By analyzing the potential risks, such as mechanical properties, fungal attacks, and fire hazards, this paper provides suggestions for the preservation of timber buildings with different climates in China.