On site archaeological museums: types of protection

The decision to preserve, in their original context, even the most fragile artefacts, such as floor and wall coverings, or to exhibit the delicate stratigraphic and unbaked clay manufactures, has favoured the spread of archaeological museums in situ, by interventions aimed at the preservation of archaeological remains. Archaeological museums represent a particular typology capable of relating history through its ruins. Therefore, it is not a museum having typological and functional characteristics that answer to codified museum-graphical and display rules. The arrangement and the public opening of the archaeological sites in recent years have been the object of discussions, debates and interdisciplinary collaborations. Making an archaeological site a museum means ensuring its preservation, valorizing it in its context, protecting it and, at the same time, creating the best conditions for its use by the community. Today it’s possible to distinguish different approaches in different Countries, dictated by different environmental and climatic conditions and by the specific characteristics of each site. This article develops a classification of types of protection for archaeological sites, for to understand the more or less effectiveness of the solution in some emblematic interventions, to preservation of the finds from weather (sun, rain, etc...). An example is represented by the site of Villa del Casale in Piazza Armerina in Sicily: its cover in translucent material, built in 1950, has caused a greenhouse effect and phenomena of condensation, with consequent damages to the pictures and mosaics. But, as far as trasparent covers are concerned, some examples have been realized in different Countries; they manage to combine well the demand of transparency of the envelope with the demand of preservation