Research on the Thermal Performance and Dimensional Compatibility of Insulation Panels with Chinese Fir Facings: Insights from Field Investigations in Qiandongnan

The traditional timber architecture of Qiandongnan represents a rich cultural heritage. However, urbanization has led to the replacement of these structures with concrete and brick buildings, resulting in the loss of both functionality and cultural identity. To bridge the gap between traditional architecture and modern building needs, this study conducted field surveys to extract key design parameters from local structures, enabling the development of a modular framework for Structural Insulated Panels (SIPs) based on the dimensions of traditional dwellings. Four types of SIPs were developed using Chinese fir, OSB, EPS, and XPS, and their thermal performance and heat stability were evaluated through theoretical analysis and hot box testing. The results show that all specimens met the required heat transfer coefficient. The combination of OSB and XPS showed a slightly lower heat transfer coefficient of 0.60 compared to Chinese fir, which had a coefficient of 0.62. However, the Chinese fir–XPS combination provided the longest time lag of 6.34 h, indicating superior thermal stability. Due to the widespread use of Chinese fir in local construction and its compatibility with the landscape, this combination is ideal for both energy efficiency and cultural preservation.