In the course of a restoration in the late 19th century the minster, especially its pediments were replaced almost entirely. Shortly after this restoration, severe damage was observed on the renewed pieces. The minster is built of molasse-sandstone of poor quality with a large hygric expansion. A similar stone was applied during this restoration. In 1997 to 2001 after exhaustive research, conservation was applied to wide parts of the minster of Salem Abbey. Within the prior research conservation for the molasse-sandstone including filling of fissures with silica-sol with quartz sands, lining and washing on the same base and a consolidation using silicic-acid-ether was developed. The work was revised in 2009 and 2013. The results were all-in-all positive. A large amount of stones originally intended for replacement can now be held in place. In areas strongly exposed to rain new gaps could be observed.
Keywords: Molasse-sandstone, sandstone, conservation, restoration, fissures, gaps, delamination, flaking, silica-sol, silicic-acid-ether, moisture.