2Colour changes and reactivity to SO of some cladding stones at the “Gran Teatre del Liceu” (Barcelona; Spain)

Publisher Summary This chapter describe the study conducted to select the most suitable cladding stones for the Great Theatre "Liceu" of Barcelona (Spain) from a series of pre-selected stones. It focuses on the color change and reactivity of cladding stones to sulfur dioxide (SO 2 ). SO 2 polluted atmosphere exposure was conducted because even very low atmospheric concentrations of SO 2 can lead to decay of building stones. Six different stones were preselected: three light colored sedimentary and three dark colored metamorphic stones. In order to assist the final selection, these were subjected to a climatic chamber SO 2 exposure. Although no visual color changes were observed, significant color changes were detected by colorimetric measurements. These changes were related to stone reactivity to SO 2.