New-build with an exposed brickwork façade
Basel, Switzerland
Planning 2016-2021
Construction 2021-2027
Natural History Museum + State Archives BS.
Overview
Client
Canton of Basel-Stadt, Switzerland
Architecture
EM2N AG, Zurich, Switzerland
Team ZPF
Basil Amrein, Selina Arnold, Enrico Cristini, Damian Dängeli, Dëmin Dimitry, Patrick Gressler, Katarína Kormanàkovà, Luis Looser, Roberto Plaza, Dario Ruff
The Natural History Museum Basel and the State Archives of Basel-Stadt are two cultural institutions with a long tradition, whose collections and archives are of significance to the Basel region and beyond. They make historically and scientifically important knowledge available to the public and together form the regional repository of natural and cultural history. The operations of the Natural History Museum Basel and the State Archives of Basel-Stadt are to be continued in a shared new building. The government decided in favour of a site outside the old town, near St Johann station.
The project perimeter for the new building ensemble is located in outer St Johann and covers approximately 5,120 m² of floor area. To the north it borders the plot of the former signal box at St Johann station, to the south and west the SBB railway zone, and to the east the St Johann neighbourhood. The building is 180 m long in total and is divided into five sections. It has five basement levels and five upper storeys, as well as a 41-metre tower facing Vogesenplatz.
The façade is constructed from rough fair-faced masonry and exposed concrete and is self-supporting. The total area of fair-faced masonry amounts to 5,300 m². Horizontal bands in exposed concrete are woven between the masonry sections. Each of the eight façade bays functions as a structurally independent unit. Vertical joints arranged in sections ensure that the façade can expand freely in response to temperature changes. The masonry rests on a concrete plinth running the full length of the façade, which in turn sits on the basement ceiling slab via elastomeric bearings.
To ensure the out-of-plane stability of the façade elements, these are tied back to the structural wall panels behind them with anchors. Areas of the façade that cannot be tied back to the structure are fitted with continuous vertical stainless steel reinforcement, itself anchored in the plinth and in the upper exposed concrete band. The cantilevered canopy above the delivery area forms part of the façade structure. It is formed by a post-tensioned concrete beam created as an extension of one of the exposed concrete bands.
The tower features a distinct façade design. On its north and south faces, certain areas are executed as filter masonry. This approach serves a dual purpose — aesthetic and functional: behind the filter masonry, full-storey-height openings in the structural shell are provided for building services. The upper and lower terminations of the filter sections are again defined by the concrete bands.
The architectural quality of the façade is grounded in an intensive development process. Central to this was the «cloud-around-brick» effect: an oversized 40 mm mortar joint applied wet-on-wet, which softly envelops each brick and gives the façade a shifting, almost textile quality depending on light conditions. A specially tailored mortar mix and a meticulous sampling process were essential for the project’s implementation.
All the openings in the building were designed and constructed in accordance with the stone grid. The entire façade was constructed without a single cut stone or special-sized block.