Dal progetto al cantiere: il restauro delle superfici architettoniche come rispetto di autenticità e valori culturali. Alcuni esempi

This paper addresses the restoration of architectural surfaces within fortified heritage, interpreting them as privileged repositories of historical, cultural, and material values embedded in architecture. Starting from a theoretical framework grounded in the principles of critical restoration ‒ particularly authenticity, minimal intervention, compatibility, and recognisability ‒ the study emphasises the central role of masonry surfaces as records of natural and anthropogenic transformations over time, whether intentional or not. A substantial part of the contribution is devoted to the results of research on medieval surface finishes in the Autonomous Province of Trento, developed also within the APSAT project. Through the census, technological and chrono-typological analysis of masonry, and the selective use of diagnostic investigations, the paper highlights the interpretative value of mortars, joints, and their workmanship ‒ elements that are often fragile and vulnerable, yet fundamental for the stratigraphic and historical reading of built fabric. The paper then offers a critical reflection on the quality of restoration practices, showing how insufficiently informed interventions may compromise the legibility and transmission of the cultural values of historic buildings. These considerations are supported by the analysis of three emblematic case studies in the Trentino context ‒ Castel Penede in Nago, the castle of Castellalto in Telve, and the Civic Tower of Trento ‒ where the restoration project is conceived as an integrated process of knowledge and operative action. In conclusion, the contribution reiterates the need for a solid theoretical and technical education of the conservation architect and for continuous dialogue with skilled craftsmen, recognising the care of architectural surfaces as an act of cultural and ethical responsibility that is essential for the conservation and conscious transmission of built heritage.