In the context of the institutional collaboration between the Soprintendenza speciale per i beni archeologici di Roma (SSBAR – Mibac)
and the Istituto Superiore per la Conservazione (ISCR – MiBAC) we opened a “Pilot worksite” aimed at drawing up a set of guidelines for interventions on plasterwork, painted decorations and stucco work, characterized by their present underground condition, with specialist restorers certified by ISCR and supported by the studies and specialist scientific analyses of the same Institute.
State of Conservation
The scientific experts from ISCR first proceeded to characterize the forms of decay and the constituent materials in order to guide the methodological choices adopted in work to secure the decorations. These analyses comprised:
- Biological studies to identify alterations due to bio-deterioration, contamination and microorganisms. For example, we identified some microorganisms belonging to the group of meristematic fungi that can produce dark pigments. Although serious phenomena of biological attack were not identified in the wall examined, the experts suggested preventive disinfection of the surfaces before consolidation and cleaning work to counter potential biological attacks during conservation work. We found that the use of cellulose pulp during conservation may have led to the development of phenomena of biological growth. Even the “cotton gauze” used by restorers to adhere surfaces may encourage the growth of fungi since it is composed of cellulose. Similarly, the use of wood for scaffolding must be avoided at all costs.
- Microclimatic monitoring with the use of data loggers in the worksite to record the temperature and relative humidity. During the summer the interior is constantly colder than the outside. Condensation phenomena occur when the masonry surface has a temperature less than or equal to the dew point. During the period between May and September, the relative humidity was between 85 and 100%. Furthermore, sudden decreases in the external RH have repercussions inside: the water present within the structures may evaporate and/or condense.
- Study of constituent materials and state of conservation of plasterwork. The ISCR’s Materials Testing Lab carried out a series of tests on the samples collected. The preparatory layers of the plasterwork turned out to be based on lime mortar and red pozzolana; the plasters had differing compositions including lime, marble powder and pozzolana granules; cocciopesto and spathic calcite granules; grey limestone granules, marble powder and red pozzolana etc.
The paint layer preserved in this room presents extensive decohesion problems caused by sulphation.
Direct observation and the results of the specialist analyses outlined allowed us to determine that the wall studied presents different types of finish resulting from several phases of execution with paint layers and plastered parts. In this specific instance, the painted surface presented a red decoration on a white background. On the surface, there was an adherent and coherent dark brown deposit. A thick and adherent calcareous concretion covers the surface painted in red; in areas where the concretion has lifted or detached, the paint layer has stuck to the concretion itself.
The conservation treatments, guideline entries and cost analyses were broken down as follows:
- Graphic documentation
- Disinfection and disinfestation treatments
- Protective coating
- Removal of unsuitable plasterwork
The complete documentation is on the SSBAR and ISCR records.
The company A.T.I. di Borzomati, Galanti e Fiorani participated in the works.
The following participated in the studies and the drafting of the Guidelines, alongside C. D’Angelo, Conservator (Group coordinator):
- Daniela Gennari: Conservator
- Carla Giovannone: Conservator
- Antonio Guglielmi: Conservator
- Anna Maria Marinelli: Conservator
- Valeria Massa: Conservator
- Barbara Provinciali: Conservator
A group of technicians and experts from the Institute participated in consultancy activities:
- Marco Bartolini: Biologist
- Carlo Cacace: Manager of the Microclimatic models section data management
- Lucia Conti: Geologist
- Maria Antonietta De Cicco: Diagnostic Expert Biology Laboratory
- Giancarlo Sidoti: Chemist
- Mara Bucci: Graphic documentation expert
- Angelo Rubino: Photographic documentation expert