Thon restores historic waterside warehouse in Trondheim city centre

Cultural treasure in Trondheim being converted into modern offices with history in the walls

Originally built in 1857, Bryggen 15 is now being converted into an office building with a rough, modern and flexible style in which new and old coexist in harmony. Timber construction provides good acoustics and a pleasant indoor climate.

"Old and new come together beautifully in the entrance. Just inside the main entrance, which still has the original timber and windows, a glass facade has been created over two floors that makes it possible to see a cross section of the building," says Property Manager Ståle Dullum from Thon.

Scheduled opening in autumn 2025: vacant premises on the top floor

Standing next to a wall from the year of construction, Dullum talks to one of the traditional craftsmen about how it is to become the end wall of one of the meeting rooms.

"It will be very clear which elements are new, since there will be a number of plaster and glass walls. We're also removing some of the structural connections between floors and walls that do not have historic value to allow more light to enter and to improve the dynamics of the office environment," says Dullum.

Read more details about Brygge 15 at thoneiendom.no

"It's fantastic that more people can experience historic Trondheim"

"We're very pleased to see that such an important part of our city is becoming more open and accessible. The fact that more people can experience historic Trondheim through the use of the buildings is fantastic," says Silje Taftø Petersen, architect and antiquarian at the cultural heritage management office in Trondheim (shown below).

There are several waterside buildings on Kjøpmannsgata that have stood vacant for several decades, which has limited the possibility for locals to see them from the inside. Petersen hopes and believes that we can create a positive ripple effect on completing the renovation of Kjøpmannsgata 15.

Kjøpmannsgata 15 to be restored to its original appearance

"We're restoring the building to its original appearance, with wooden poles on the Nidelva side," explains development director at Thon Trond Are Martinsen.

Martinsen has been active in the project since it began in 2019. Together with the municipality of Trondheim, Thon is removing the concrete poured under the building by the previous owner in the 1980s. The cultural heritage management office is pleased with this decision.

"We're delighted that Thon has taken an interest in and understanding of the history of the waterside buildings and therefore decided to return the building to its original appearance on the river side. The concrete foundation of the building from the 1980s, which extends into the river, has been ridiculed by many and is commonly referred to as the 'pigsty' and 'dentures'," says Petersen.

Interior details like the pulleys on the top floor are being kept in place. These were originally used to load goods into the building and are among the few remaining pulleys on Kjøpmannsgata.

More sustainable to renovate and re-zone than build new

"Nowadays, it is important that we retain and reuse as much as possible. This project involves large structural elements, a lot of timber and concrete, so it is important to reuse as much as possible," says Martinsen.

The focus of the cultural heritage management office is to retain as many of the original elements as possible and only replace rotted timber with high-quality wood. According to Petersen, Kjøpmannsgata 15 is unique in that it has timber from the 1800s and extensive concrete construction from the 1980s in the very middle of the building.

"This has required quite a few compromises to create usable office spaces. Because of major structural decay in several of the buildings on Kjøpmannsgata, several kilometres of timber construction have been carried out in recent years," says Petersen.

In addition to pouring concrete, the previous owner also made a number of other upgrades in the 1980s. These included reducing the number of floors from six to five due to a low ceiling height and adding six skylights. The exterior cladding was also replaced and the facade windows moved and replaced with a different style.

"The exterior cladding and facade windows are being returned to a traditional style and we are adding extra insulation and making other improvements. The building's appearance will be the same as in the year 1913.  We will also have skylights to meet current requirements for daylight and indoor climate in keeping with the policies of the cultural heritage management office for daylight and placement," says Martinsen.

Revolutionary testing of fire safety

"Thon should be commended for financing the revolutionary testing of incineration time and fire resistance of new and old timber constructions! This just goes to prove that we can achieve acceptable fire safety without the extensive use of plaster," says Petersen.

The tests have been carried out as part of a partnership between Rambøll, SINTEF and graduate students of NTNU in Trondheim. The findings can be used for comparable cultural historical buildings elsewhere.

"(…) This not only retains the building's aesthetic and historic value, but also ensures its life span and protection from future fire hazards. The results were impressive, with some walls achieving fire resistance for up to 90 minutes,, says Dag Denstad, head of fire engineering at Rambøll.

Directorate for Cultural Heritage on site to facilitate preservation of the medieval foundation

To utilise the rooms in the old building as best as possible while at the same time strengthening the structural elements, the lift and stairwell have been moved to the middle of the building. The foundation under the building is also being renovated.

"After removing all the floor boards, we saw a bunch of boards in the river below us and I was afraid we had hit a boat! But the Directorate for Cultural Heritage gave the go-ahead: the boards found under the floor were actually most likely from the 1700s or 1800s, but the foundation from the Middle Ages was important to preserve," says a relieved Martinsen with a chuckle.

"You'd be hard pressed to find a better officelocation in Trondheim"

The basement of Brygge 15 has shared bicycle parking and cloakrooms. And it's only a short walk to public transport hubs and public parking. There's a lift between all floors, open plan offices and meeting rooms, as well as good lighting conditions.

"You'd be hard pressed to find a better place to have an office," claims Dullum, who looks forward to moving into his office in the building.

If the promise of Bakklandet and Nidelva is enough to get you out the door, you'll find a wide variety of cafés and restaurants just a short walk away from Brygge 15.

"Several parks along the shores of Nidelva are also close by. Walk past the cathedral on your way down to the Marinen park or take the Old Town Bridge to Bakklandet and enjoy a cup of coffee outdoors on a sunny day," recommends Dullum.