Résumé en anglais
This paper is a general review of the problems of conservation of materials and stresses the need of understanding traditional techniques before making modern substitutes. The papers submitted by authors in this section are reviewed. Causes of decay are considered briefly. The problems of craftsmen is touched upon. Comments are made on the general problem of atmospheric pollution and the universal but localized problems of vibrations. Regular inspections and a strategy for preventive maintenance of historic buildings is recommended in order to reduce decay and save money.