During the initial phase, following the detachment of fragments and small portions of plaster, scaffolding was erected to closely examine the lesions in the vaults of the left aisle. The lesions, mainly longitudinal with some branching, have been attributed to seasonal cyclical movements and the 2016 earthquake event. To ensure structural safety, deep and systematic injections of the lesions with lime-based products were performed.

Due to the presence of decorations, preliminary washing of the lesions could not be performed. Therefore, the consolidating product (superfluid hydraulic filler binder) identified for the structural consolidation of the vault, already successfully used to restore lesions in the vaults of the Basilica of Assisi, containing cellulose fibers that retained the water of the ‘mixture, allowed a hardening reaction of the mortar without the need for prior wetting of the lesions present, avoiding the risk of damaging the decorations present in the intrados.

Injections were made from both the extrados and intrados to ensure complete filling of the lesions (after grouting the lesions in the intrados by inserting witness tubes to signal complete saturation of the treated lesion). The extrados surface was perforated to allow injection, while the intrados surface was treated with progressive mortar injections.