Unveiling the Effectiveness of Innovative Commercial Coatings Used for the Preservation of Natural Stone—A Contribution

The preservation of natural stone heritage is still a major challenge for the scientific community. This topic assumes a greater importance since it impacts economic and socio-cultural values. Recent research has indicated that water action and microorganism activity are among the major contributors to the deterioration of this material. Despite the emergence of new protective solutions in the market, some constraints still need to be overcome. This study aims to contribute to unveiling the effectiveness of innovative commercial coatings on the preservation of natural stone frequently used in built heritage. Four different commercial coatings are assessed regarding their compatibility with the substrata and effectiveness against UV radiation, water action, and microbial development under accelerated ageing. The protective solutions are tested on five different Portuguese lithotypes, including carbonate and silicate-based stones. Colour change is measured to assess compatibility, while profilometric change of the stones’ surface and antimicrobial potential are evaluated to determine their effectiveness. Our research demonstrates that the solution that exhibits the greatest compatibility and effectiveness potential is composed of modified silanes and siloxanes derivatives.