Stones surfaces and elevated architectural grillworks of historic buildings, due to their predominantly outdoor location, suffer from deterioration factors, including air pollution, soluble salts, relative humidity (RH)/temperature, biodeterioration and by shelling in 1914. The durability and longevity of the structure can be enhanced on proper restoration techniques are adopted in order to arrest the degradation, contaminants, damages and environmental forces. The mineralogical identification and organic substrates were evaluated using X-ray diffraction (XRD), Fourier transformation-infrared spectroscopy (FT-IR), optical microscopy (OM) and Munsell colour chart for rock identification. Presence of silicates, feldspar, calcite and hornblende confirmed the rock to be sandstone on agreement with Munsell colour specifying the pale soft yellow (quartzose sandstone) and inorganic binding agent of calcite as cementing material was also confirmed through FT-IR analysis. Reduced feldspar peaks affirmed the rock has weathered for ages. The results provided the base for the formulation of repair and restoration work of high court building and for modern conservationist. © 2021, The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.