Expressive natural stone cladding with precision-fit protection
Churches aren’t built very often these days, but that’s not the only unusual thing about this expressionist-style new building in Munich’s affluent suburbs. In addition to ceramic tiles, local Nagelfluh stone was also used. The solid natural stone had to be prepared to meet various requirements for both interior and exterior use.
Rupert Mayer was a Jesuit priest who, among other things, opposed National Socialism as part of the Catholic resistance in Munich and was beatified in 1987. The “Apostle of Munich,” as he is also known, is the patron saint of the gleaming white, light-filled new church, which was built between 2015 and 2018 in the municipality of Poing, an eastern suburb of the Bavarian capital. The distinctive design of the Blessed Father Rupert Mayer Church impressed not only the Association of German Architects—which honored the building with one of Germany’s most prestigious architectural awards, the Große Nike—but also the local community. While the Baumeister envisioned a crystalline form when designing the “solitär”—a freestanding building that stands out stylistically from the surrounding structures—the congregation is reminded of winter sports. They affectionately call their new church “God’s Ski Jump.”
15,000 ceramic tiles cover the 30-by-30-meter-high polygonal roof structure, causing it to shimmer when the light hits it just right. The 3-D ceramic tiles were handcrafted and glazed by m&r Manufaktur in Ransbach-Baumbach based on a design by the architectural firm, using slip casting—a molding process from traditional porcelain production. In contrast to the delicate shapes of the tiles, the massive base section of the facade, as well as the wall base and floor area inside the church, are made entirely of polished Brannenburger Nagelfluh from the Upper Bavarian gravel plain by Grad Nagelfluhwerk GmbH & Co. KG.
Nagelfluh is a conglomerate rock containing rounded rock fragments of various origins. Rock fragments from the Central Alps were transported by mountain streams into the Alpine foothills, where they were deposited and subsequently filled and consolidated by the overlying pressure of younger sediments and lime precipitated from the groundwater. Due to the high proportion of binding material, the natural stone appears homogeneous overall despite the presence of various rock inclusions. It formed during the Pleistocene, making Nagelfluh a relatively young rock. Its appearance is characterized by open and clearly visible pores. The Brannenburg Nagelfluh originates from a Nagelfluh massif in the region of the same name, which formed during the Würm Glacial Period. The rock has been quarried there since the 10th century. In southern Germany, Nagelfluh can be seen in many buildings; examples include the facade and the large portal of Ludwig Maximilian University in Munich, as well as the foundations of Munich’s Frauenkirche and the Old Technical City Hall. Its use in new construction is less common, as seen at the Seliger-Pater-Rupert-Mayer Church in Poing.
The nine-centimeter-thick facing masonry made of solid Nagelfluh needed special protection against graffiti, as well as other environmental influences. Due to the natural stone’s typical structure, the substrate has varying levels of absorbency. When removing dirt and paint, residues could remain on an unprotected facade.
The choice fell on the preventive surface and graffiti protection system PSS 20 from PSS Interservice GmbH. The protection system met the specifications of the client, the Catholic Church Foundation of St. Michael: The coating, which is barely visible to the naked eye, is fully reversible, and its polysaccharide- and carbohydrate-based formulation—that is, sugar and potato starch—met the requirements for environmental friendliness. “It is a purely plant-based product without any chemical carriers,” assures Bernd Pfennig, the PSS Interservice technical consultant responsible for the protective coating measures on the sacred site, “which is why it is also frequently used by historic preservation authorities.” PSS 20 forms an ultra-thin film on the surface of the Nagelfluh and protects against graffiti as well as general contaminants such as splashing water, de-icing salts, and dog urine. “Natural stone has a capillary system; contaminants easily penetrate the stone through its open pores and alter the surface’s appearance. The porosity of natural stone is therefore the actual cause of soiling, and specific surface protection systems provide a solution here,” explains the expert. The natural stone facade nevertheless remains completely open to water vapor diffusion; the small amount of moisture that does penetrate can be immediately released again via the vapor phase.
Read more in STEIN 8/2019.












