A rusting steel facade for historical artefacts

The Swiss National Museums have an unusual new collection centre at Affoltern am Albis. The most striking feature about the new building is its façade. It is made of rusting steel. 

A metaphor for aging

Most clients insist their building avoids at all cost precisely what the client in this case called for: a corroding façade. The designers of the façade, Stücheli Architekten, use the rusting steel structure to symbolise the aging process of the artefacts housed inside the building. This presented the Basler & Hofmann team with a challenging assignment. They had to create a façade design that could rust but was also durable. 

An innovative solution using structural steel

It would have been obvious to have used so-called weather-proof steel to resolve this, which would enable the rust to form a top layer that inhibits corrosion. However, this protective mechanism fails when used on a façade that is directly exposed to the weather. For this reason, ordinary structural steel was used on the building rather than weather-proof steel. A certain portion of the steel actually becomes corroded every year. Calculations have been made to show that the steel plates only need to be 1 millimetre thicker. An innovative supporting framework is being used to ensure the durability of the façade which will allow rain water to drain away freely. This is an example that could catch on as it opens up new areas of application for structural steel.  

Client:

The Federal Office for Buildings and Logistics (BBL)