#16 The Green Heart – the New Calwer Passage in Stuttgart

In our latest podcast, our colleague Florian Starz gives an insight into the planning, realisation and sustainability of our facade project Calwer Passage. The building complex designed by Christoph Ingenhoven at the geographical centre of Stuttgart is completely greened on three facade sides and on the roof.

On the roof, a mixed forest of numerous native tree species such as oaks, pines and various bush species has been created. Various climbing plants, shrubs and bushes have been planted along a total length of 2 km on the facade. The plants were selected together with specialists. In a small-scale test setup, it was tested in advance in as much detail as possible how fast the selected plants grow and which aids are suitable for climbing.

From a Previously Sealed Area to a Green Oasis

The “urban heat island” effect in Stuttgart’s cauldron can be significantly reduced by planting on facades and roofs – the new Calwer Passage is an important step in this direction. The plants provide shade for the facade and help to naturally air-condition the building through evaporative cooling. During heavy rainfall events, which are becoming more frequent as a result of climate change, the substrate on the roof can store water.

Another pleasing effect of green facades has already occurred on the roof forest of the Calwer Passage, as Florian Starz tells us: The building in the middle of the city has become a habitat for numerous insects and bird species. The new Calwer Passage is a beautiful eye-catcher, its facades and the forest on the roof have transformed the previously sealed area at Calwer Platz into a green oasis.

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