Nordic authorities and stakeholders gathered for a workshop on how to convert office buildings into housing

Read the full inspiration catalogue here

Diving into the action area of changing use of the existing buildings

Building on the inspiration catalogue and the action areas, further discussions between the Nordic authorities and the sector led to exploring the area of conversion and changed use further. The workshop gave participants opportunities to exchange experiences and perspective on how existing buildings can be adapted to meet changing needs. The workshop initiated with an attempt to define the potential. However, no common numbers on what the potential is in converting office spaces to housing from all the Nordics countries were identified. Instead, indicative results from several rapports were shared, which indicate a potential where there is a housing request.

A Danish report on the potential for the development of more homes in the existing building stock, the need versus potential for homes are analysed, showing that 40.000 to 70.000 additional homes can be created from the existing housing stock with an estimated need until 2040 of 100.000 to 150.000 homes. In addition, a report from BUILD showed that conversions are mostly made into large residential buildings (200.000 m2 annually) and to both detached single-family housed and cinemas, theatres and others without accommodation (100.000 m2 annually).

The European Commission made a report on conversion of offices into affordable housing, showing that office conversions in the seven largest cities in Germany could provide up to 60.000 housing units. Furthermore, market research in the Netherlands showed that empty office spaces could yield 11.500 homes, and nationwide in the EU there is seen a residential conversion potential of 2.1 million m2 of office spaces.

The City of Oslo made a report on better use of the existing buildings, and in Finland a report has been made, mapping around 4.31 million m2 of vacant offices. In Stockholm and Göteborg a report found that over 100 homes can be found with small renovations and almost 1000 homes with slightly more extensive renovations. In addition, a report from Sweden found that 2.500 new homes are added every year though conversion of buildings.

The discussions at the workshop covered topics such as the definition of changed use, common challenges seen in projects of converting buildings, economic considerations and the role of regulations in supporting the use of the existing buildings.

Participants discussed how the definition of changed use differs in national approaches but agreed that there is a common need for greater clarity and consistency. Examples showed how Norway has developed a guidance to clarify when a project will trigger the change-of-use requirements, and Finland already permits certain changes of use despite deviating from the local plans. In addition, Finland also added to the construction act that a building may be repaired in accordance with the original construction method used at the time it was built. 

The participants also identified some technical, economic, administrative and strategic challenges, including meeting modern standards as daylight, ventilation, fire-safety and accessibility, navigating requirements and access to renovation finances, differing in interpretations across municipalities and balancing building quality with increase reuse of the existing buildings.

To address these challenges, potential solutions, such as clearer guidance and checklists, tighter coordination between planning and building authorities, and more proportionate requirements and technical solutions, were discussed. Economic considerations were also discussed, highlighting the absence of a comprehensive overview of regulatory cost and that the combination of regulatory requirements can affect project viability. In Norway, they are currently exploring financing mechanisms to support renovation and transformation projects, an example is giving a grant to the elderly to help them upgrade their housing to be able to live there for longer. Regulatory flexibility was also discussed, providing an example from Finland, that offers extended temporary‑use permits, and Norway, where municipalities can grant full or partial exemptions from the building regulation as long as the building still lives up to the purpose in the building regulation.

In Denmark, an example of clear communication is that the Building Regulation’s guidance on energy consumption, explicitly writes that when changing use from office to residential, the Building Regulations do not consider this a change that triggers new requirements, as both uses are heated to above 15°C and have similar indoor climate requirements.

The workshop highlighted the value of continued Nordic knowledge sharing on the topic. By bringing together authorities and stakeholders from the Nordic region, the workshop provided an opportunity to exchange practical experience and identify common areas of interest related to the efficient use of the existing building stock. The discussions and insights gathered during the workshop will contribute to the ongoing work in the Nordic Sustainable Construction programme in the Circularity Work Package and the transition towards a more resource-efficient built environment. 

Real life example of changing the use of a hotel

The workshop finished with a site visit, which took place at the former Hotel Saga, built in 1962 with a 1984 extension. In 2021 the hotel was converted into a mixed‑use campus for the University of Reykjavík and student housing. The 4^th to 7^th floor now contains student apartments, while the remaining parts of the building serve as university functions.

During the renovation, the ground‑floor slab, most interior walls, and many original furnishings were preserved, while completely replacing the roof, HVAC plant and all windows with energy‑efficient glazing and sun‑shades for the residential floors. All mechanical, electrical and plumbing installations were renewed and hidden within the ceiling to simplify cleaning, in the student housing part of the building. In the rest of the building the installations were made visible to ease access and maintenance. Furthermore, new emergency exits and upgraded doors were added to meet current safety standards.

The project achieved a 20‑25 % cost saving compared with new construction, and many salvageable elements (doors, fixtures, etc.) were sold on the second‑hand market, illustrating a circular‑economy approach. Despite the building’s more complex structure than initially expected, the conversion demonstrates how an existing structure can be adapted to new societal needs, extending its useful life while providing a sustainable, economically efficient solution for the city.