On 13 June 2008, renovation work started under the supervision of Adolf Krischanitz, a former student of Karl Schwanzer at Vienna University of Technology.
At a cost of 31.9 million euros, the carrying capacity of the steel structure was adapted to the requirements of the building code.
The ceilings were cleaned of asbestos and the original glass roof was made shatterproof.
The large window profiles were replaced with energy-saving double glazing.
The work also entailed providing additional space by re-erecting the 75 meter long original porch from the 1960s and by lowering the area in front of the structure, transforming it into an atrium crossed by an access bridge.
A six-storey office tower on the former parking lot was added with lettering describing the building's purpose.
On 20 September 2011 Federal Minister Claudia Schmied attended the celebration of the completion of the building, following the awarding of the BC21 Art Award for young, innovative artists.

On 15 November 2011, the building was reopened after Krischanitz fitted it out as a museum with well organized exhibition spaces and a cinema.
The overall effect is an open museum structure with a total of 2,275 m² (24,500 square feet) exhibition space on the ground and upper floors.
The exhibition space in the basement houses the permanent exhibits from the Wotruba Foundation (with some 500 works in stone, bronze, and plaster, 2,500 drawings, 1,500 prints, and 14 oil paintings) as well as a restaurant and an art studio for children.
The shop of the Museum, the "Salon für Kunstbuch" (Salon for artistbooks) is an installation by the Austrian Artist Bernhard Chella that the 21er Haus bought in 2011.
The Austrian Artothèque, which allows civil servants and publicly owned corporations to take out up to four artworks on loan for up to one year, will be located in the second basement and is open to the general public since September 2012.
The new cinema with the original seating and paneling from Expo 58 opened in March 2012.

The museum is a branch of the Belvedere, focusing on "Austrian art of the twentieth and twenty-first centuries and its embedding in an international context".
The opening exhibition under the title: "Schöne Aussichten" (English: fine prospects) presented artworks from Lucio Fontana, Andrea Fraser, Marcus Geiger, Florian Thorsen, Lois Weinberger, Franz West und Heimo Zobernig.
There will be three large exhibitions per year open five days a week.
On 13 June 2008, renovation work started under the supervision of Adolf Krischanitz, a former student of Karl Schwanzer at Vienna University of Technology. At a cost of 31.9 million euros, the carrying capacity of the steel structure was adapted to the requirements of the building code. The ceilings were cleaned of asbestos and the original glass roof was made shatterproof. The large window profiles were replaced with energy-saving double glazing. The work also entailed providing additional space by re-erecting the 75 meter long original porch from the 1960s and by lowering the area in front of the structure, transforming it into an atrium crossed by an access bridge. A six-storey office tower on the former parking lot was added with lettering describing the building's purpose. On 20 September 2011 Federal Minister Claudia Schmied attended the celebration of the completion of the building, following the awarding of the BC21 Art Award for young, innovative artists.
On 15 November 2011, the building was reopened after Krischanitz fitted it out as a museum with well organized exhibition spaces and a cinema. The overall effect is an open museum structure with a total of 2,275 m² (24,500 square feet) exhibition space on the ground and upper floors. The exhibition space in the basement houses the permanent exhibits from the Wotruba Foundation (with some 500 works in stone, bronze, and plaster, 2,500 drawings, 1,500 prints, and 14 oil paintings) as well as a restaurant and an art studio for children. The shop of the Museum, the "Salon für Kunstbuch" (Salon for artistbooks) is an installation by the Austrian Artist Bernhard Chella that the 21er Haus bought in 2011. The Austrian Artothèque, which allows civil servants and publicly owned corporations to take out up to four artworks on loan for up to one year, will be located in the second basement and is open to the general public since September 2012. The new cinema with the original seating and paneling from Expo 58 opened in March 2012.
The museum is a branch of the Belvedere, focusing on "Austrian art of the twentieth and twenty-first centuries and its embedding in an international context". The opening exhibition under the title: "Schöne Aussichten" (English: fine prospects) presented artworks from Lucio Fontana, Andrea Fraser, Marcus Geiger, Florian Thorsen, Lois Weinberger, Franz West und Heimo Zobernig. There will be three large exhibitions per year open five days a week.
21er Haus