RWTH Alumni Above the Roof-Tops of Cologne – or: The Cathedral – a Never-Ending Construction Site


It is windy on Friday, February 28, 2020. Not too windy, however, for us to take the boxy construction elevator running along the facade of the Cathedral that brings us to the first station of our special cathedral tour.

We are a little worried about the noises the elevator makes as we go up, but the higher we go, the easier it gets to ignore them because the view is so amazing: the people down below look just like little ants and the trains sitting on the tracks of the central train station remind us of a model train set. After a few-minute ride, we have arrived on the scaffolding erected on the roof of the Cathedral, 45 meters above the ground.

Our group consists of fifteen RWTH Alumni plus Alumnus Dr. Thomas Schumacher, one of the engineers on the Cathedral’s construction team. He’s the one who invited us to tour the unique building inside and out with a particular focus on the Cathedral’s building history, architecture, and restoration efforts.

On the scaffolding, we are getting a first glimpse of the numerous changes in architectural style over time, including the techniques used when any restoration or maintenance work was done. Also, depending on the century or decade, one can recognize the different types of stone that had been used for various individual elements. Among others, there is trachyte from the Drachenfels region, basalt lava, sandstone from Württemberg, or Bozanov in the Czech Republic, the latter being what is currently in use. The decision for one type of stone over another was – and is still made – mainly in terms of highest similarity to the original; but compatibility or (geo)political factors also play a role.

Each of the respective sculptors’ desire to put their own particular spin on things is also reflected in style. In the 1980s, for instance, even the recreation room and toilet for the workers under the roof truss of the nave were specially designed. They were modeled after the “public utilities” from 19th century Berlin, as the then chief architect of the Cathedral’s construction team had studied in Berlin.

In the roof truss, we get to admire the steel construction from 1859/60, which had plenty of advantages compared to a roof made of wood; most importantly, it was argued at the time, the fact that it offered better fire protection.

Here, under the giant roof of the Cathedral, Dr. Schumacher, offers us some additional information about steel production (puddle iron, flux, and welding iron) and arch statics (tensile versus compressive stress). Having studied mechanical engineering and having received his doctorate in architecture with a thesis on the Cologne Cathedral, our guide is highly versatile and knowledgeable. This interdisciplinarity of the entire structure can be grasped at every station, and so we now devote ourselves more to art history and craft traditions in the model chamber. It is located on the second floor of the north tower and contains the collection of models of figures, statues, gargoyles, or facade elements. Around 60 employees from various trades nowadays work on the maintenance of the Cathedral - stonemasons, sculptors, roofers, carpenters, and painters as well as scaffolders.

One of the highlights of the tour comes with our ascent to the crossing tower. On the platform at the height of about 70 meters, the view and the wind are breathtaking. The tower is located above the intersection of transept and nave. We have a panoramic view over Cologne, the Rhine, and of course, the two main towers and the roofs of the Cathedral.

After descending the narrow spiral staircase, we reach the triforium, a corridor at the height of 20 meters that leads once around the entire interior of the Cathedral. The Richter window from 2007, known for its randomly arranged color squares, radiates a colorful light into the interior as we stand in front of it.

We realize that, unfortunately, a photo could never do justice to the fantastic, colorful glow we are now experiencing. So we spiral down a staircase for the last time, and after this very enlightening two and a half hour tour, we finally arrive back at the base of the Cathedral.

Later, as we are enjoying some Kölsch beer and other Cologne specialty foods such as “halve Hahn” and “kölsche Kaviar,” we all agree: It was a very special alumni get-together. Thank you very much, Dr. Schumacher!