The advantages of (mass) timber construction are countless, and yet we still see relatively few wooden buildings. And certainly considering really tall buildings, which are traditionally built of steel and concrete. However, wood is a very clever invention of Mother Nature. Wood is strong, durable, smells and feels good and is renewable. This has been known for years in the Nordic countries, and that now seems to be changing in the Netherlands as well. Niels Castelein, structural engineer at engineering consultancy company Sweco (with Swedish origins), explains why.
Why would you want to go tall with timber?
“Our cities continue to grow, while building space is often limited. Therefore it makes sense to build tall. Wood is easy to process industrially, and offers opportunities for digitalization in the design process and extensive prefabrication and robotization in production. This allows the construction time to be shortened up to 50%. In addition, it reduces risks and nuisance when building in densely populated areas. Building with timber is cleaner and quieter, that is good news for the city of the future! ”
What exactly is so smart about building with wood?
“Building with timber has countless advantages. It is a natural resource free of carbon emissions. In fact, carbon is stored in wood. The amount of carbon stored in a cubic meter of timber is roughly equal to the monthly electricity consumption of 8 households! Using timber as a building material enables us to store carbon in the built environment for a long period of time. The low density of timber provides a double advantage considering nitrogen emissions crisis: the number of deliveries to the construction site can be reduced, and lighter, possibly even electrically powered equipment can be used. Shorter construction time and a limited number of employees on site contribute to further reduction.
Another advantage is that timber structures commonly can be disassembled in parts with relative ease, with a possible high residual value of the elements. These elements can be recycled in the built environment.
So many advantages, but why do we rather turn to concrete and steel?
"That's what we call in in the Netherlands the chicken or egg story. What was first? There are only few references, which causes uncertainty. Building with concrete and steel is known, almost standardized. A safe choice. And ultimately, construction is about (predictable) costs. This is understandable, because we want to build affordable. I strongly believe that together, with companies from the entire chain, we can make timber construction competitive and interesting.
In addition to the price, aspects as acoustics and fire safety are also seen as risks. One can remember the houses from the early 20th century, where wooden floors are terribly noisy. Fortunately, we no longer have to fear that nowadays: comfort and safety score high. ”
What is needed to accelerate timber high-rise buildings in the Netherlands?
“In general, you don't see many real high-rise buildings in the Netherlands (> 70 meters). This has to do with regulations and available space. In addition, we do not yet see the slenderness of high-rise structures in concrete or steel in timber high-rise buildings. The low density of the material is a factor in this.
The development therefore requires not only courage from clients, but above all that we continue to innovate. Investigate smart structural systems and the dynamic properties of timber towers. And also: push boundaries safe and deliberate, again and again”
What is Sweco's experience with timber construction?
“Thanks to Sweco's Nordic origins, there are decades of knowledge and experience in building with wood in our company. Knowledge of structural engineering, fire safety and building physics, among other things, allow us to approach projects integrally. A great example of Sweco’s expertise is the "Mjøstårnet" tower in Brumunddal, Norway. Mjøstårnet is the tallest timber building in the world (87.5 meters) to date.
I certainly look forward to work on such a “high”light of timber construction in the Netherlands, bring on that wooden century! ”