After the cleaning procedures carried out during a recent restoration work, the Matera Cathedral’s (UNESCO World Heritage Site) façade needed the application of a water repellent treatment. Aqueous emulsions of silanes/siloxanes, also in a mixture with acrylic polymer and an alkyl/alkoxysilanic resin (by BEL CHIMICA S.r.l. and PHASE restauro S.r.l), have been tested as representative of the most used formulations in the restoration of buildings in Italy, especially in the last decade.

This paper focuses on the best practices to be adopted for the identification of the suitable protective product in terms of effectiveness, harmfulness and durability, in particular respect to photo-aging and thermo-hygrometrical aging. The conservation materials have been tested in situ and in laboratory on a stone block expressly extracted from the monument.

The chemical composition of the products and their degradation processes were characterized by means of FT-IR and PY-GC-MS. The performance of the treatments was evaluated, both in laboratory by permeability, color and capillarity measurements and in situ by non-destructive techniques (IR reflectance spectroscopy, color measurements, water absorption tests by contact sponge).

Silane/siloxane emulsion presented more pronounced degradation phenomena after artificial aging, while the mixture of silanes/siloxanes and acrylic polymers decreased the permeability to water vapour.

在最近的修复工作中进行了清洁程序之后，马泰拉大教堂（联合国教科文组织世界遗产）的外墙需要进行防水处理。硅烷/硅氧烷的水乳液，以及与丙烯酸聚合物和烷基/烷氧基硅树脂的混合物（由BEL CHIMICA Srl和PHASE restauro Srl提供）均经过测试，可以作为意大利建筑修复中最常用的配方代表，尤其是在过去的十年中。

本文着眼于在有效性，有害性和耐久性方面，尤其是在光老化和热湿法老化方面，用于识别合适保护产品的最佳实践。保护材料已在从纪念碑明确提取的石块上进行了现场和实验室测试。

通过FT-IR和PY-GC-MS对产物的化学组成及其降解过程进行了表征。在实验室中通过渗透性，颜色和毛细血管测量以及通过非破坏性技术（红外反射光谱，颜色测量，接触海绵的吸水率测试）就地评估处理的性能。

硅烷/硅氧烷乳液在人工老化后表现出更明显的降解现象，而硅烷/硅氧烷和丙烯酸类聚合物的混合物降低了对水蒸气的渗透性。