Post-event report | Stuttgart - Minna Riska: Timber instead of reinforced concrete

This year’s November Talks in Stuttgart, which had the theme “Building without concrete”, were wrapped up by Minna Riska of MDH Arkitekter (Oslo). After the previous lectures offered interesting journeys through clay construction and energy-efficient hybrid building, an office specialising in construction projects utilising CLT (cross laminated timber) was up next.

The starting point for the intensive discussion of CLT was the competition-winning master plan of the Moholt student village in Trondheim (2013). “The master plan consists of three fundamentally independent projects”, says Minna Riska. After the complex, which was originally constructed between 1963 and 1970, had been in use for 50 years, it was considered necessary to redevelop it into a high-quality, functional and contemporary district . The goal was to better integrate it into the urban environment and to create additional living spaces for 400 students. Therefore, from the remains of an old, sprawling car park sprang a new, identity-shaping neighbourhood centre featuring five tower blocks, including commercial spaces on the ground floors, a district library and a nursery school. Originally planned as conventional structures, the buildings were developed as pure CLT constructions featuring reinforced concrete semi-basements as per the explicit wishes of the building owners. Furthermore, they also wished for the structures to meet the passive house standard. Neither fire protection nor a high-rise building classification – with nine floors and a building height of 28 metres – pose problems. “The great thing about timber constructions is that they remain standing for longer than reinforced concrete when under the influence of fire”, explains Riska. “The actual challenge was the issue of sound transmission within the cross laminated timber components”. This was solved by a corresponding sound decoupling strategy between the spaces and within the component connections. The office also developed an XXL shingle facade that is able to withstand the Norwegian climate by resisting all temperature-related timber movement.

Furthermore, an additional, very recent CLT project made a positive contribution to the regional infrastructure: the Evenes School (2021) in the northern Norwegian “village of 3,000 souls” as Riska describes it, of the same name. The merging of two schools made the expansion of one of the school buildings a necessary endeavour. MDH Arkitekter suggested a timber construction. It provides suitable rooms for the highly variable class sizes of ten to up to forty students, an auditorium for school and cultural events as well as a gymnasium featuring a small swimming pool for all residents. This also made the new school building a social and cultural meeting point for the entire village. For her third project, Riska presented the Sarpsborg Senior Highschool, a design that MDH Arkitekter collaborated on with Longva Architects.

The architect concluded her lecture by addressing the question of why she enjoys working with timber. For her, the answer is clear: “Timber has abundant benefits for the environment”. It has a positive CO2 footprint and is easily reusable. While building with the material requires more meticulous planning beforehand, but, because of its high degree of prefabrication it can then be used reliably, quickly and flawlessly on the construction site. “CLT can also be used as a raw material for surfaces within interior spaces. It is a highly resistant material and easy to repair”, explains Riska. “Users are often pleasantly surprised by the spatial quality”. Cross laminated timber is, without doubt, a top-quality and efficient alternative to reinforced concrete.

You can download the high-resolution images here.

The follow-up reports, also from the other locations, will also be made available to you gradually. You will then find these data under the following link.

You can find all dates of this year's November Talks on our website www.novembertalks-festival.com. The website also contains brief video clips of interviews with the speakers.