More know how to pave the way for more wood construction
Laminated wood elements match concrete in terms of both strength and price, while offering significant environmental benefits. Therefore, greater efforts should be made to promote wood in construction, according to a report which was commissioned on behalf of the Swedish Government and the Nordic Council of Ministers.
Lone Wiggers, an architect and partner at C.F. Møller Architects, has analysed in detail the barriers to using wood as a construction material. She points out that familiar objections such as fire and damp risks, noise and cost can easily be overcome by drawing on the latest knowledge and introducing new building site routines.
At a time when society is actively looking for ways of protecting the environment and reducing carbon emissions, the construction sector should be focusing more on using wood as a building material. This was the basis of a report from the Nordic Wood in Construction Secretariat – an initiative launched by the Swedish Government and the Nordic Council of Ministers.
“Significant efforts have been made to improve the energy efficiency of our buildings, but the sector hasn’t made much headway when it comes to reducing carbon emissions from the actual building materials. Using wood as a building material has the potential to change that, reducing the carbon footprint of our buildings by using the only renewable construction material,” says the secretariat’s 2019 annual report.
The report also highlights the fact that the Nordic countries – with their extensive, sustainably managed forests – are particularly well-placed to promote timber construction.
Wooden buildings as carbon sinks
One Scandinavian firm of architects that regularly uses wood as the main construction material is C.F. Møller Architects, and Lone Wiggers, a partner at the firm, says:
“Wood is a flexible material offering huge architectural potential, because it’s so easy to work with and handle. It is also extremely strong, and can easily replace concrete, especially in homes and other buildings with shorter spans. And because wood is lighter than concrete, the cross-laminated timber elements require smaller cranes and foundations. Furthermore, the elements can be installed much faster, reducing construction time considerably.”
“There are huge benefits to using more wood in building design. Wood stores carbon while the trees are growing in the forests, and releases it again when it rots. By building with wood, we can store carbon, and at the same time use waste wood for heating, energy and biomass. Moreover, a healthier indoor climate can be created by using wood,” she says.
Concerns about damp, fire and noise
While C.F. Møller Architects has designed wood buildings in Sweden and Norway, wood is conspicuous by its absence in Danish projects. In recent years, Lone Wiggers has therefore studied the reasons why wood is not being used in Danish construction projects, and shared her findings with politicians and colleagues from the construction industry.
“The common perception is that wooden buildings pose a real fire hazard, are prone to dampness and have poor sound insulation. All the cases of dry rot and mould scare people off. However, the fact of the matter is that lots of wooden buildings are being constructed in countries with wet and cold climates.” With smart planning, logistics guidelines on handling the building materials and digital simulation of the construction process, it is easily possible to keep wood dry. And as far as noise is concerned, well-documented solutions are available that more than live up to the official building regulations,” says Lone Wiggers.
Too light for skyscrapers
Lone Wiggers mentions the lack of know-how about high-rise wooden buildings in particular. This is slightly ironic, given that many of the older buildings in Copenhagen are multi-storey timber-frame structures made of approx. 50 per cent wood and horizontal divisions made of timber beams with clay filling. But the old craftsmanship techniques have all but been lost. C.F. Møller Architects is currently involved in the construction of approx. 140,000 square metres of wooden buildings, including one of Sweden’s tallest solid-wood buildings in Kajstaden in Vesterås, which has just been handed over. However, lightweight wooden structures above a certain height are exposed to the wind.
Photo: Kajstaden in Vesterås (Sweden). Copyright: C.F. Møller Architects
“Heightwise, the economic sweet spot of CLT construction is between three and 11 storeys. The higher up you go, the more weight must be added to the construction to prevent it from swaying too much, for example in the form of a concrete core or partial concrete decking. Or, as in another 22-storey building that we’re also constructing in Vesterås, by constructing the lower floors from concrete and using wood for the upper levels,” says Lone Wiggers.
Photo: Hybrid Tower in Vesterås (Sweden). Copyright: C.F. Møller Architects
FACTS: C. F. MØLLER ARCHITECTS
- C.F. Møller Architects is one of Scandinavia’s leading architectural firms, which for 90 years has been producing award-winning projects in the Nordic region and worldwide.
- The company was founded in 1924, and currently has approx. 350 employees.
- C.F. Møller Architects has offices in Aarhus, Copenhagen, Aalborg, Oslo, Stockholm and London.
Architect and Partner at C.F. Møller Architects.