But the building was starting to age and was in dire need of thorough redevelopment. To carry out this project in the best spirit of the original designer, David Chipperfield Architects had stepped in. "As much Mies as possible" was the motto of what was ultimately a six-year, concentrated, elaborate and detailed undertaking. For example, most of the panes of the transparent glass façade were damaged – only four were still intact. However, since the slender supports would have had to be widened for modern double glazing – which would have been an aesthetic no-go – the team looked for and found a manufacturer in China who could produce the panes in their original dimensions.   

Working with the original was a priority throughout the project – and the patina, as well as traces of use, were not to be completely eliminated. Although more than 10,000 granite floor tiles, among other things, were removed, restored and replaced in the foyer, they still show traces of visitors from the past. The utility shafts, clad in exquisite Tinos marble, were also preserved true to the original. Any damage to original materials was merely concealed. The historic lighting fixtures were also preserved, but were converted to energy-saving LED technology.

With all their desire to preserve the building, the Chipperfield team nevertheless added some sensible and sensitive changes to the building. For example, there is now a lift connecting the exhibition spaces in the basement, which is discreetly built into the brown oak veneer cloakroom block. A corresponding cloakroom was created in the basement, where there was previously a depot. As part of the efficient organisation of space, an old picture storage area has become the new museum shop. The design there, however, is true to the original style: oak veneer, black granite and exposed concrete. And matching switches from Gira – simple and elegant. Presumably in the spirit of Mies van der Rohe.