We are in Northern Europe where it rains a lot and gets very cold, so we built a kind of winter coat made of glass
– Roberto Gonzales

The new Addenda Architects-designed Bauhaus Museum, which takes the form of a 100m (328ft) long “Black Box” of reinforced concrete on stilts enclosed within a glass envelope, has been opened in Dessau, Germany.

The outer envelope measures 105m (344ft) long, 25m (82ft) wide and 12m (39ft) high – and is made up of 571 triple-glazed glass panes. Inside, the Black Box allows no natural light in, but provides the optimal climatic conditions to preserve the 49,000 exhibits in the Bauhaus Dessau Foundation collection.

With its stilts rising five metres above visitors' heads, the unit is accessible via two stairwells from the ground floor, where there is the Open Stage, a flexible multipurpose space with a lobby, ticket desk, cafe and shop, and 600sq m (1,970sq ft) of space for changing exhibitions.

Roberto Gonzalez of Addenda Architects said: "Our basic concept for the museum was to create a large, flexible space so that exhibitions and workshops can take place without feeling restricted in any way by the architecture. We obviously had to integrate this idea with the requirements for the museum: it had to provide an area of 1,500sq m (16,150 sq ft) for the collection, protect the exhibits from direct sunlight and offer ideal climatic conditions.

"This is how we came up with the idea for the Black Box, a closed concrete cube that floats above the ground. At almost 100m (328ft) in length and 18m (59ft) in width, the Black Box is supported by two staircases, which are 50m (164ft) apart. It doesn't have any supporting columns.

"Of course, we couldn't just leave the space below the Black Box open. We are in Northern Europe where it rains a lot and gets very cold. So we built a kind of winter coat made of glass. This glass façade protects the building, but it also created additional space for exhibitions, events and offices on the ground floor."

Gonzalez also revealed that the Black Box is constructed "like a bridge", in that it is bent upwards at the ends, which will allow it to settle into a horizontal line over a period of years, pulled down by its own weight and that of its exhibits and visitors.

"That's not going to happen immediately but in the course of the next maybe 20 years. Because the Black Box is made of concrete and steel, the outcome can't be calculated exactly. There is some wiggle room – which is much larger than is standard."

Addenda was chosen to design the Bauhaus Museum Dessau following a competition that received 831 submissions. Construction took just under two-and-a-half years, with a €28m (US$31m, £25m) project budget, and Germany's Chancellor Angela Merkel was on hand to cut the ribbon at the opening ceremony.

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