Danish studio AART Architects have been named the winners of an international competition to design a new extension for the Viking Age Museum in Oslo, Norway.

The firm were chosen ahead of 11 rivals to create a “new signature, forward looking setting” for one of the country’s most popular museums – which exhibits a number of Viking Age boats and artefacts – after the judges unanimously approved the bold, circular design.

Called Naust, or Boathouse in English, the 9,300sq m (100,000sq ft) extension will be a natural continuation of architect Arnstein Arneberg’s listed 1926 Viking Ship Building, with the new circular volume connecting the existing north and west wings and circling around an inner courtyard.

The new rooms will be double height, allowing visitors to enjoy the museum’s collection of Viking ships exhibited along a sequence of open corridors.

“The extension will continue the calmness and clarity of the Viking Ship Building and transform it into a dynamic, coherent sequence of exhibition spaces and dissemination possibilities,” said the architects. “The museum will be linked together in a simple, but highly distinctive architectural statement, creating a flow of movement through the rooms and a fluctuating journey through the Viking Age.

“The museum’s extension will allow visitors to compose their own experiences on the basis of time, desire and need.”

The judges revealed the design was chosen for its feasibility, relatively low cost and potential for future development.

The project is being developed by Statsbygg – Norway’s Directorate of Public Construction and Property – on behalf of the education ministry.

The organisation’s CEO, Harald Nikolaisen, said: "The jury concluded that Naust provides a very good solution to a complicated challenge. The new building will secure and preserve the unique, popular and fragile Viking age collection, which is one of the world's foremost cultural monuments."

AART, who will collect NOK650,000 (US$79,000, €69,600, £55,500) for their win, will now enter the final negotiation phase for the project before working on a final design. Afterwards, a political debate will be held to establish the amount and source of funding.

Statsbygg estimate that at the earliest, construction will begin in 2020 ahead of a 2022 opening.

The competition win follows the recent architecture competition for a Viking museum in Trelleborg, Denmark. Copenhagen studio PLH Arkitekter won first place with a design inspired by a lost Viking shield.