Diagnostica, sperimentazione e metodologia di monitoraggio per la conservazione della facciata della chiesa di Santa Maria di Nazareth a Venezia

This contribution illustrates the experimental research related to the restoration completed in 2018 for the conservation of the façade of the church of Santa Maria di Nazareth in Venice and the monitoring methodology for the evaluation of its conservation over time. The church boosts a baroque façade unique in Venice as it is made entirely of Carrara marble, a limestone with a saccharoid structure that has proved unsuitable for the aggressive lagoon climate. Over time, the façade has undergone an uninterrupted process of restoration operations. The last one proved to be necessary following an unexpected event in July 2013, when an acanthus leaf collapsed to the ground. The diagnostic investigations, the choice of the consolidating agent and the verification of its performance were supported by an experimentation both in situ and in laboratory, in collaboration with CNR of Florence. The final objective was to reach a compatible conservative restoration for a possible improvement of results over time and also to favour an effective retrieval of scientific data in case of future interventions. With this in mind, an indirect survey campaign, with image shooting technologies such as laser scanner and drone, was planned with the involvement of University IUAV to have an exhaustive knowledge of the present vulnerabilities. A Digital Historical 3D model was designed to carry out analyses for assessing the vulnerability of the facade, preparatory to future interventions with respect to any worsening of the state of decay.