Non destructive testing to perform service of the evaluation of conservation works

The best practices of a conservation work pass through a pilot yard. In this preliminary step conservation works are tested in a small representative area: cleaning, desalination, application of consolidants and/or water-repellent treatment. Most of the tests are carried out on site using a small number of non-destructive testing - rugged, reliable and at low-cost - aimed at measuring some physical/chemical features of the surface under conservation, both before and after the application of the product. In this paper a survey about of the most diffused protocols currently used in Italy, is presented. A critical review of benefits and drawbacks, possibilities and problems offered by specific testing systems in collecting evidences, will be carried out.