The Aalto office was one of fifty-three internationally renowned architecture offices from fourteen countries that were invited in 1955 to design a block of flats for the 1957 Interbau Exhibition. The drawings for his first ‘Vorprojekt Haus 19’ are dated February 1955, and show a twelve-storey block with an asymmetrical ground plan and ten apartments per storey.

The next plan, ‘Vorprojekt Haus 15’, had a different site and orientation. Again twelve storeys high, the house was divided into two wings with entrances from the intermediate courtyard. The prefabricated concrete units are clearly visible in the façades, which have dominating balconies that Alvar and Elissa Aalto thought of as a kind of open atrium. The idea was to provide each flat with some of the contact with nature that the single-family house offers. The smallish flats are set around the living room and the adjoining atrium balcony.

The plan that was finally built, ‘Haus 16’, resembles the ‘Vorprojekt Haus 15’, though the site had again changed. Aalto placed a free-form screening wall between the two stairwells at ground floor. The building contains 78 apartments on eight storeys. One of these was furnished for the 1957 exhibition with Aalto furniture to plans the Aaltos had originally drawn up for the H55 exhibition in 1955 in Helsingborg.