Since the beginning of the site-wide conservation campaign, research on improving modern integrations to archaeological structures has proved to be important, particularly for the most widespread and/or complex problems that affect them. The most visible example of efforts being made in this direction is the short- and medium-term experimental roofing for the Insula Orientalis I, installed in 2006. The main aim of our experimental work is to establish working procedures based on results obtained in the short term, together with medium-term monitoring. In this way the tested approaches can be replicated by the Soprintendenza for complete conservation projects, emergency works, or indeed for essential routine maintenance. Trials for small-scale model interventions have already been carried out in the last few years and include projects for modern lintels and small masonry reintegrations.
In general, our approach is to keep the need for modern integrations to a minimum by restoring and maintaining existing structures when they are still structurally sound. Modern elements (e.g. roofs, lintels, etc.) were installed in the site by Amedeo Maiuri and his successors over the years and they are only replaced when it is unavoidable or when new integrations are necessary for conservation reasons. In these cases we aim to make our work as similar as possible to what already exists on site, without emphasizing new works, so as to avoid changing the site’s image and allowing original fabric to be read. This is relatively easy to achieve when working on masonry structures, but a different approach has to be taken for other types of structure, for example, when substituting wooden elements (beams, lintels, planks, etc.) or floor slabs and roofing. In particular, we are developing standard procedures for lintels, where different materials are used depending on how exposed it will be to the weather (for example, using wood if the lintel is under cover, whereas coated metal I-beams are used outside). Standard procedures are being developed with an emphasis on improving the quality of materials used and on research to ensure its durability over time.
Recently we have identified the most common materials used for reintegrations (e.g. timber, stone, lime, sand, bricks), as well as complete architectural elements that need installing (barriers, doors, gates, skylights, etc.), in order to recommend quality products that are available in the Vesuvian area. We hope that this will help to reduce the general tendency of different approaches being used each time works take place on site and to improve the general quality of the works themselves.
As for the structures, the need to improve conservation methodologies for the site’s decorations was recognized early on. Much of the technology available today is highly effective and has been tested with success in recent years, but sometimes completely satisfactory solutions to Herculaneum’s problems have not yet been found. In addition to the normal causes of decay which affect decorative surfaces, two other factors are particularly problematic: 1) the difficulty of controlling environmental factors, especially water; 2) widespread changes to the original chemical/physical equilibrium of ancient floor and wall decorations, caused by the extensive conservation treatments which were undertaken at the time of the ancient city’s excavation, with materials and techniques which at that time were innovative, but which today we know to be highly incompatible with the conservation of the original surfaces.
In parallel to the emergency works campaign, which has been carried out across the site since 2006, various pilot projects have been taken forward in order to develop specific methodologies for conserving different types of wall and floor decorations, such as frescoes, wall plasters, stone and mosaic decorations, beaten earth floors, etc.
In addition to various trials carried out within the emergency works campaign (for example, the Suburban Baths in 2008) and the programme of scientific research with a range of external partners, a more in-depth project has been launched for the decorative features in the House of Neptune and Amphitrite, which puts into practice the Herculaneum Conservation Project’s interdisciplinary approach. As a case study, the nymphaeum suffers from Herculaneum’s basic problem: it is impossible to completely eliminate all causes of decay and therefore a coordinated approach is needed to reduce damage to decorative features through targeted interventions, monitoring and continuous maintenance. The difficulty of managing the nymphaeum’s environmental conditions and the conservation problems is just one example that represents the problems faced across the site. Conservation activity is therefore carried out on several fronts: managing rainwater and rising damp, reducing soluble salts on surfaces, consolidating and securing of decohesive, exfoliated and disintegrating surfaces, eliminating vegetation, continuous monitoring of environmental conditions and developing guidelines for routine maintenance.