CONSOLIDATION AND HYDROPHOBIC TREATMENT OF NATURAL STONE
Since almost 35 years silicon-organic compounds are used as consolidating and hydrophobing agents for natural stones. There is evidence that on buildings the durability of hydrophobing treatments is limited to 10-15 years (fig. 1). It is well known that consolidating silica gels, formed by ethyl silicates, show a great number of shrinking fissures due to a continuous loss of structural water. However, a loss of the effectivness could not be detected (Sattler and Snethlage 1988). As a consequence of a consolidation and hydrophobation the formation of contour scales was observed in particular cases. (Wendler and Sattler 1989).