Calcium alkoxides as alternative consolidants for wall paintings: Evaluation of their performance in laboratory and on site, on model and original samples, in comparison to conventional products

In the field of cultural heritage conservation, wall paintings treatment is a particularly complex issue, which requires a suitable choice of materials. In this paper, two innovative calcium alkoxides, calcium tetrahydrofurfuryl oxide [Ca(OTHF)2] and calcium ethoxide [Ca(OEt)2], are proposed as new products for the consolidation of wall paintings. They were developed during the NANOMATCH European project and their efficacy, compatibility with the substrate and durability were evaluated in comparison with commercial products on both model and real samples. Model samples were exposed in four different sites around Europe to investigate the treatments' behaviour under different climatic conditions. The main research results are reported here: alkoxides showed to be a good option for wall paintings' consolidation especially in presence of certain binders and pigments. Finally, an impact testing device was used for the first time for the evaluation of the consolidants' efficacy and thus proposed as a reliable methodology for their performance assessment.