Materials and technologies in Art Nouveau architecture: Facade decoration cases in Italy, Portugal and Poland for a consistent restoration

The results of a diagnostic survey on the materials of several art nouveau buildings in Italy, Portugal and Poland are here presented and compared, as a first contribution to their understanding and, hence, compatible restoration. In particular, the façade decorations were investigated for the appraisal of their materials and technologies, often neglected in current maintenance/restoration works and so cancelled, leading to a severe loss in architectural image. The diagnostic campaign is aimed to highlighting some possibile preservation guidelines for Art Nouveau architecture at an European scale