Il degrado degli stucchi serpottiano a Palermo in relazione alle condizioni ambientali di conservazione

This work is part of a demanding project, called “Progetto Serpotta”, performed since 2000 in cooperation with Soprintendenza Beni Culturali of Palermo. Aim of the project is the restoration of the unique stucco's artworks moulded by Giacomo Serpotta and his co-workers end of 17th -beginning of 18th century.This paper is focused on the problem of salt efflorescences, that are widely present in all of the churches and oratories restored in the framework of “Progetto Serpotta”. Particular attention is given to the relationship between the constitutive matter of the stuccoes, as analysed by means of both X ray diffractometry and optical microscopy, and the salts composition, as analysed by means of both X ray diffractometry and ionic chromatography. Results provide better knowledge of the causes for the formation of efflorescences. Furthermore, they give precious information to work out a proper restoration plan and, on the other hand, to set the optimum environmental conditions for a long term conservation of the stuccoes.