Calwer Passage

Architecture
Ingenhoven Architects, Düsseldorf/Germany
Tennigkeit Architekten, Stuttgart/Germany

Planning time
2017 – 2020

Construction time
2018 – 2021

Services by Werner Sobek
Facade engineering, inc. green facades (WP 2 – 8)
Planning for the building services engineering and
the irrigation systems required for the green facades
High-level access planning for the facades
Sustainability consultancy and DGNB certification

Client
Piëch Holding, Stuttgart/Germany

Rendering
Ingenhoven Architects, Düsseldorf/Germany

The Calwer Passage sits in a central location in the geographical heart of Stuttgart, the state capital of Baden-Württemberg. The majority of the existing building, which was constructed in the 1970s, is being replaced by a new structure that is covered in greenery and stretches up to a height of seven storeys. Parts of the original building’s basement levels are being preserved and incorporated into the section of the development that lies adjacent to the city’s ‘Stadtmitte’ suburban railway station. The Calwer Passage’s historically listed glass shopping arcade that leads across to Calwer Square is also being retained and integrated into the new building complex. In addition to its subterranean transport links, the development features retail space and restaurant facilities on the ground floor and a number of apartments and a large amount of cutting-edge office space on the levels above. Some of the greenery on the exterior of the building is planted in projecting structures attached to the series of opaque, horizontal bands that wrap around its facades. These structures, which are linked together here and there by climbing plants on vertical trellises, also flank the building’s generous expanses of highly insulated glazing that provide solar and glare protection for the users inside. The overall design of the project’s facades includes integrated irrigation and drainage systems for around 2,000 large planters and provides access for gardeners to look after the greenery they contain. The foliage on the sides of the building is complemented by the wide-ranging selection of densely planted trees and shrubs on the roof spaces. Thanks to all of this vegetation, the Calwer Passage helps create a fresh urban environment with a natural, healthy climate and clean air to breathe. The plants and the substrate structures underneath them temporarily store some of the water produced during periods of heavy rainfall. In addition, the greenery can help reduce concentrations of particulate matter in the surrounding area and combat the so-called ‘urban heat island’ effect that would otherwise overheat the heavily built-up district in the summer months. As a result, the project will significantly improve the microclimate of the site.