The intervention plan for the conservation of historical-artistic assets included a series of activities aimed at ensuring the preservation and restoration of various artifacts. Initially, several diagnostic investigations on the materials were planned in order to determine the nature of the layers superimposed on the original surface, with the aim of identifying the type of intervention to be done. 

In the specific case of Porta Angelica, there was a double chromatic layering, due to the replacement of a tower with a furnace in the 1920s, as designed in the context of the Spaccarelli-Piacentini project. The analyses were carried out both on the materials and on the construction techniques in order to recognise and characterise the units relevant to the various construction phases, thus obtaining useful information to guide the conservative intervention on the features. Field analyses were also carried out to characterise some parameters relating to the degree of cohesion of the material, thus obtaining objective data for the operational choices to be made for the consolidation intervention.

The restoration operations began with the removal of unsuitable metal elements and the preliminary cleaning of inconsistent surface deposits. The maintained metal elements were subjected to cleaning and protective treatment before proceeding to wet cleaning of the surfaces. Subsequently, samples were taken for chemical cleaning. Before proceeding with the consolidation phases, the surface was thoroughly cleaned and the partially detached elements were shored to prevent damage during subsequent operations.

For areas of greater artistic value, such as coats of arms in stone material, cleaning was determined based on specific tests. Before grouting and styling the joints, laboratory and field tests were carried out to identify the composition and particle size of the original mortar, maintaining consistency with previous aesthetic choices.

The plasters, after the integration of the gaps and the restoration of the adhesion to the wall support, were veiled with pigmented lime milk, guaranteeing visual continuity with the previous restoration interventions.