Field observation of the deteriorating materials on heritage buildings and a comprehensive analysis of their respective weathering products using various laboratory techniques are conducted for an archaeological ruin in Bangladesh. The fifteenth–nineteenth century buildings were investigated through empirical observation of their in-situ weathering characteristics to attempt to determine the possible relation between their deterioration and the surrounding environment. Results from physical and chemical analysis of water, mineralogical and elemental analysis of the weathered materials suggested that deterioration occurred primarily due to the environmental effects with the specific identification of the salts thenardite, gypsum and nahcolite as weathering products.