Published 2019-11-14

People say the most sustainable square meter is the one that isn't constructed. However, construction is crucial in order to tackle the housing shortage and to deal with the substantial demand for premises in the city centres. An upward extension is a far more sustainable solution than new construction - and in the best of cases, it is made from wood. 


As one of eight architecture firms, Semrén & Månsson Architects are taking part in the research project Timber on Top, financed by Vinnova. The project has researchers and actors in the construction industry collaborating, aiming to investigate how prefabricated wooden building systems can contribute to densification through superstructures. Maria Hamlin is an architect at Semrén & Månsson and responsible for the research collaboration. In her opinion, the project is a win-win situation for the office and the industry's development in the field.  


- We are faced with two challenges: For environmental reasons, we have to stop using concrete in every construction, and we need to find new ways of urban densification that are both profitable and sustainable. By combining the light and climate-smart material wood with the technically complex upward extensions of the existing resources, we're able to take a significant leap forward in both areas. 

A continuous challenge with superstructures is weight. In most cases, a building's foundation work is adapted to carry the original building and nothing more. Therefore, upward extension often requires substantial reinforcement of the building's foundation, which, in turn, often results in added weight, increased material consumption, and consequently high cost. 

- A superstructure made from wood weighs less, which makes the entire construction easier to implement. It also opens up for extensions in more sensitive areas, such as older buildings in the city centres, and that is actually where the densification is needed the most, says Maria Hamlin. 


Semrén & Månsson's contribution to the research project is an upward extension of a 1960s building in Gothenburg. It's a project that although it's not constructed from wood is a great learning example due to several technical challenges. 

- For wooden superstructures to gain appeal, we need to both generate new insights and promote the existing knowledge. With Timber on Top, we are linking participants from different areas of the value chain, so that they together can drive development forward, says Mathilda Norell, a doctoral researcher at the Luelå University of Technology and responsible for the architectural part of the project. 


That means the research project is entirely in line with the Architects Declare appeal - eleven action points developed to accelerate the transition to climate-smart construction, to which Semrén & Månsson is one of the initiators. Knowledge sharing and upgrading existing buildings to extend their useful life as an alternative to demolition and new construction are among the action points, which also includes persuasive communication with clients.  

- Many still consider wood to a bit of a wild card that requires more from everyone involved compared to good old concrete. But with knowledge and good examples, architects will get a better way of demonstrating the many financial and environmental advantages of using wood, says Maria Hamlin.