Preserving buildings while reducing carbon footprint

“Buildings account for 40 per cent of our carbon footprint in Sweden. This makes it important not just to build efficient new buildings, but to look after the existing building stock,” says Tor Broström, Professor Emeritus at the Department of Archaeology and Ancient History and Conservation.

Together with his colleague Gustaf Leijonhufvud, Senior Lecturer in Cultural Heritage, he gives examples of what can be done. Visby has many culturally valuable older buildings. In one old building, the choice has been made in recent times to insulate the outer wall with hemp lime.

“This is a lime mortar into which hemp fibre has been mixed, which insulates better than ordinary thermal mass. So this wall insulates better than the original one but without really affecting the appearance,” says Leijonhufvud.

Not just old buildings

It's not just the oldest buildings that need to be made more energy efficient, Broström notes. One example is the Björken neighbourhood, built in the 1970s, just outside the Visby city wall.

“Most people would say that these buildings have little cultural value. But the Planning and Building Act says that all buildings without exception must be treated with caution. When striving to meet our ambitious climate energy targets, the 20th century buildings present the biggest challenge. How should we apply the concept of caution to these types of buildings?”

Coming to the right decision

It may involve, for example, adding insulation to the facade, replacing windows or glazing balconies.

“Technical solutions are a necessary but not sufficient condition. So our research mainly focuses on planning processes and decision-making. We've done a lot of work on standards and policy instruments in this area to help the players involved come to the right decision for the individual building,” says Leijonhufvud.

Annica Hulth