Testing methods and criteria for the selection/evaluation of products for the conservation of porous building materials

Abstract

This paper is a review of the literature that addresses the testing of products and tools for stone conservation. Cleaning products and tools are considered, as are products for consolidation and for the surface protection of natural and artificial stones (e. g., mortars or bricks). After an outline of the historical development of testing methods from the mid-nineteenth century to the present day, the development of the field is discussed with particular regard to the parameters that are measured, the measuring methods and evaluation criteria. This paper also discusses the weaknesses still existing in current methodologies, the aspects that should be investigated in greater depth and the increasing use of non-destructive testing methods to improve the evaluation of the long-term performance of treatments.