The heaviest stone he used at the bottom of the church weighed 1.2 tons. Matthias Wittner pushed the block between the other blocks with seven millimeters of play, by hand. It takes patience, lots of patience, but that’s part of the business. And actually it doesn’t matter whether a stone weighs 300 kilograms or 800 kilograms or even more. “The law of levers,” says Steinmetz Wittner, “plays a very important role for us.”
It is no ordinary renovation that is taking place here in Nördlingen. But St. George with the Tower of Daniel, visible from afar, is no ordinary church either. The monumental building in the Gothic style was completed more than 500 years ago: It is the only large church in the world built from moon rock that was formed when an asteroid hit the Nördlinger Ries 14.5 million years ago. The builders at the time didn’t know anything about it, so they didn’t realize that suevite, as the rock is called, is not necessarily a material for eternity. “Some of it is already crumbling down if you just stroke the stone,” says Nördlingen’s master builder, Jürgen Eichelmann.
And so Nördlingen has actually had the church renovated again and again for decades. Wittner has been doing the work on the façade since 2014. Not only is he a stonemason, he also studied restoration and specializes in medieval buildings. For the renovation of St. Georg, Wittner and his employees work every stone by hand. According to historical records, he even makes the tools himself in his own forge in his workshop: explosive irons, pointed irons, chisels, also a device called a tooth surface . In this way he can work the stone roughly, work out the edges neatly and level the surfaces, just as his predecessors did centuries ago. “It’s a few thousand strokes per piece,” says Wittner. It sometimes takes a day to process a stone.
Stonemason Matthias Wittner has to fit all the stones precisely and measure them again and again.
(Photo: Florian Fuchs)
A few thousand strokes or rubbing over it with a modern device, that makes a difference. If it is not so important to the builder or if the structure is not of such high priority, the latter also happens every day when it comes to renovations in Germany. On Daniel, however, this would be out of the question for neither the city of Nördlingen nor the State Office for the Preservation of Monuments. St. Georg should retain its radiance – then the renovation will take a decade. However, master builder Eichelmann, architect Rainer Heuberger and stonemason Wittner are also based on what the builders did centuries ago, because repairs could otherwise lead to damage. So it is necessary that the windows are leaky, otherwise condensation would form. Simply renovating with concrete, as in the last century, is also out of the question. “At the transition from the chancel to the nave, the church moves up to 14 centimeters in the wind,” says architect Heuberger. If you simply concrete in, the building becomes too rigid – and the movements in the wind would cause damage.
Eichelmann, Heuberger and Wittner discuss every single stone of the church. By knocking on it, they often hear if it’s damaged and needs replacing. If it sounds dull, it usually has a core fracture. These stones are then marked with a cross. While the blocks used to be knocked out with a jackhammer and thus destroyed, Wittner now uses a wall saw. This is how he gets the stone out as a whole, which may only be damaged in one spot. He can then use the rest of the suevite for minor repairs elsewhere.
Matthias Wittner made the historic tool for working stone himself.
(Photo: Florian Fuchs)
When the asteroid struck, the very rocks at the center of the catastrophe were severely caked by the heat and pressure. These are the good stones that are still intact today. They look darker, glassy. “Then we have stones from the areas that fell outwards,” says Heuberger. “They basically came about through pressure.” These stones are not glassy, just sandy, they have slight cracks after centuries of exposure to the elements. It has happened again and again that individual chunks have come loose from the church and fallen down. Nonetheless, there were never any injuries.
In 2012, Nördlingen bought sandstone from a quarry in Bamberg for 600,000 euros. It is lighter in color than the moon rock but has a clean structure and is the best substitute. Corona, delivery difficulties, so you don’t have any problems with that at the St. Georg construction site today, the work is on schedule. In his company, Wittner cuts out a large block from the Bamberg sandstone with an electric saw. He leaves a bit too much material on it, which he can then process by hand with the historic tools he forged himself. “Tool guidance like this is hardly ever taught anymore,” says Wittner. Go there, measure, then rework in the workshop, that is no longer common in most craft areas. Standards are processed there, for gravestones, for example, there are writing programs on the computer, then a radiant foil is applied – that’s it. “I learn that once and then I can do it for 40 years.”
At the church, Wittner is now standing on the scaffolding with an employee and taking out a damaged stone. With a lifting bar they carefully loosen the stone after they have worked it with the saw. Then they grab him with a belt and lift him up with chains. The stone has a contour at the front, the stonemasons left it unworked and humped at the back almost 600 years ago. “That didn’t bother me, nobody ever saw it,” says Wittner. Then the new stone is put in, a sweat-inducing job: Wittner guides a lifting iron under the stone from the side from behind, then pushes it backwards millimeter by millimeter by letting the lifting iron circle under the stone. He calls it “guidance”. Ultimately, Wittner and his colleague have to align the block: the block is tapped into position again and again. Before Wittner is satisfied, he repeatedly holds the spirit level against the outside wall.
Architect Rainer Heuberger has been working on St. Georg since 2011.
(Photo: Florian Fuchs)
He never gets bored, having to work through the huge facade of the church stone by stone. “On the contrary, it’s a privilege to be able to work on a project like this for eight years,” says the stonemason. The handles are now practiced, even if each stone has to be tackled differently. The architect Heuberger, who has been working at St. Georg since 2011, also considers the church to be his most exciting project. “You need a feeling for it, which you only get with time.”
Finally, Heuberger, Wittner and Stadtbaumeister Eichelmann will work on the sacristy. “That was the last phase of construction back then, so they took the material that they were given,” says Heuberger. The facade is now yellowish and particularly crumbly. “Even the wasps dig holes.” But even after the completion of this work, probably in the coming year, St. Georg will not be fully renovated. The city will then have to talk to the evangelical church about how they can handle the renovation inside. “There is an urgent need for action.” Nördlingen would like to complete the work by the anniversary year 2027: 600 years earlier, on October 17, 1427, the council of the imperial city of Nördlingen had decided to build the church.