OMA will design the new KaDeWe department store in Vienna, having won a competition with a design that combines shops, restaurants, a hotel and a rooftop park.

Described by the developer Signa as "a modern version of a traditional department store with a mix of shops, restaurants and hotel," the project will involve the conversion of an existing building, La Rinascente, which is split into two volumes, with retail at the front and a hotel at the rear.

The complex is accessible from outside at street level and will have a green walkway via which visitors will be able to access the roof gardens even when other elements of the development are closed. The gardens, featuring tree groves, sun decks and restaurants, will cover around 1,000sq m (10,800 sq ft) and will provide 360-degree views out across the Vienna skyline.

Also accessible from street level will be the department store shops and the hotel, which is expected to have between 150 and 165 rooms.

Commenting on the design, project architects at OMA Ippolito Pestellini Laparelli and Ellen van Loon said: "The value of department stores should be measured by their ability to engage the local context. We are very excited about the opportunity to work in the historical heart of Vienna, and with this project we intend to highlight its qualities. The building is not an icon but rather an architectural device that establishes new urban connections and public spaces through its own internal organisation."

Vittorio Radice, executive chairman of the La Rinascente and KaDeWe Group, believes the integration of functions for people to "stroll, linger and consume" points to a new opportunity and a potential future for bricks-and-mortar retailers.

"Architecture, restaurants and of course the wonderful roof park with a view over the city of Vienna will create a unique experience, a whole world of experience for the visitors," said Radice. "This project is therefore also a statement for the future and the further development of bricks-and-mortar retail which we stand for and of which we are firmly convinced."

Signa's brief had asked respondents to consider "sustainability, future-oriented utilisation and architectural distinctiveness," as well as to give particular consideration to the prominence of the location in Vienna, its significance as a meeting zone for residents and the identity of the urban development.

In naming OMA the winner of the design competition, the jury said it felt that the mixed-use nature of the design was an opportunity to redefine the street location as a shopping street.

The project is expected to be completed by autumn 2023.