Weathering and Restoration of Traditional Rammed-Earth Walls in Fujian, China

Traditional rammed-earth buildings, a key component of Fujian’s architectural heritage, are increasingly vulnerable to environmental degradation and urban relocation. This study focuses on the weathering patterns and restoration strategies of the rammed-earth walls at Zishantang, a typical 19th-century residence in Yongtai County. Through SEM, EDS, XRD, and Raman spectroscopy, eight groups of samples were analyzed to evaluate microstructural deterioration under different forms of environmental exposure. Results show that walls lacking intact soot ash coatings (“Wu-yan-hui”) exhibit greater porosity, microcracking, and mineral loss—particularly on exposed facades. These findings highlight the protective role of traditional soot–lime coatings and suggest that orientation and exposure-specific conservation strategies are essential. This study provides a scientific basis for preserving the material authenticity and structural integrity of relocated rammed-earth heritage in humid subtropical climates.