‘Wood is the solution to an existential problem in construction’




On Oude Vlijmenseweg in ‘s-Hertogenbosch, a brand new building is being built for the work development company Weener XL, circular, energy neutral and healthy. Bio-based materials are used as much as possible and in 40 years the building can be fully reused, or parts of it. An ideal stage for the event ‘Natural, wood!’ by Dura Vermeer, where, among other things, the wood’s impact, availability and business case appeared.

As we enter the entrance to the building on the former Michelin site on Oude Vlijmenseweg, the extensive use of wood immediately catches the eye. We hear that the building was designed from the inside out and that there was a focus on circular thinking. This is reflected, among other things, in wood in the floors, but also in the facade, where we also find cladding made of rice husks. For the integral design team ‘no waste, no failure’, which later became clear during a panel discussion, because the building is flexible and can be dismantled at a later stage.

In addition to the principle of maximum circular construction, we also hear that there is good news to report in the field of energy: this new location of Weener XL no longer uses fossil fuels and is completely energy neutral. The many solar panels on the roof ensure the generation of sustainable energy, and the building is heated with heat pumps. There is also a green roof with, among other things, sedum and moss to stimulate biodiversity and the final design has been fully developed in a 3D model, with BIM.

'Wood is the solution to an existential problem in construction'

Not a one-hit wonder

This combination of sustainability, circularity and health corresponds to Weener XL’s wishes for a future-proof building where employees can excel and feel comfortable. “Wooden construction belongs to everyone”, says Tim Peeters, Tender Manager and Tribal Chief (Chairman) of the Timber Captains of Dura Vermeer. According to him, wood is not a one-hit wonder, and Dura Vermeer has serious ambitions in this area: “We want to have at least 20% wooden construction for the homes we develop in 2030. We demonstrate this, among other things, in the Zangvogel projects in Vlaardingen and Hortus Ludi in Nijmegen.” According to him, we see that wood is increasingly becoming an equal alternative to traditional building materials such as concrete and steel: “You shouldn’t compare them, because wood has different properties. It radiates calm, for example.” Colleague Rob Steijn, director of the Construction and Property Development division, states that he associates wood with warmth. In addition, he highlights the sustainability features: “We want to make an accelerated positive contribution to the reduction of harmful greenhouse gas emissions. This can be accelerated with wood, because the material stores CO2 and you avoid the emissions that are released when you produce other materials.”

New business cases

Director Marijke Nas of Dura Vermeer also expects wood to play an important role in reaching the climate goals. “We can make a direct contribution with our projects and we learn together to achieve the goals.” She refers not only to colleagues, but also to collaborations that Dura Vermeer has with chain partners and customers. “We see that we would like to achieve the same climate goals and therefore share the motivations. At the same time, we work with a diversity of customers, with just as many wishes, but we can in any case note that there is an increasing awareness of this theme.” According to Steijn, there is still an acceleration in the possibilities around new business cases. For housing associations, for example, to calculate with residual value and the reusability of the building. “The material passport, where you indicate which materials have been used in a building, is also important for this. But also the change to work with CO2pricing significantly increases the attractiveness of bio-based materials such as wood.” In such a reality, the use of wood increases. Are there any concerns about material availability? “More trees grow than you can build houses.”

Pablo van der Lugt from the AMS Institute and TU Delft also agrees with the quartermaster in bio-based construction. “If you use wood, use FSC or PEFC, because then you know that the origin is guaranteed and that the size of the forest remains the same in any case. We are not used to asking about the origin, because we do not ask, for example, where bricks or concrete come from. However, tropical deforestation is still happening, so we need to make sure that we care about the sustainable availability of this material.” Van der Lugt sees wood as a significant solution to an existential problem in construction: half of the built environment consists of of materials that we have to extract, and within a century we will reach the end of their availability. “Wood was replaced by concrete in the industrial revolution, and we are now seeing another slope. If you CO2If you want to build negatively, then wood is very suitable, provided it comes from sustainably managed forests. In addition to questions about the material’s availability, we see that there are questions about the material’s technical properties.”

'Wood is the solution to an existential problem in construction'

Pablo van der Lugt: ‘If you CO2– want to build in a negative way, then wood is very suitable.’

Advantages in the construction process

It makes sense, because wood is a different material to use, with different moisture sensitivity and sealing, among other things. Steijn has previously indicated that there are risks involved, which can be seen as bears on the road. Van der Lugt qualifies that the material is primarily an option: “The entire supporting structure can be made of wood. Wood is also five times lighter than concrete, which is an advantage for, for example, prefabrication and transport.” There are also points for attention, reports Van der Lugt: “If you really go up, you need the power of CLT. Wood is also unstable in price, and material costs can change by, for example, 5 to 10 percent in 9 months. This makes the advantages in the construction process even more important. By smartly detailing the installations, you can complete the load-bearing structure faster.” He also advises paying close attention to removability: “If you work without wet knobs, it will be easier to detach later. This is important for, for example, the new business case that we discussed earlier today, regarding residual value and reusability.” You can calculate the removability with Circular Buildings, the measurement method that you will find on the website of the Dutch Green Building Council.

Underrated

Looking at the impact on reducing CO2emissions, you avoid around 1.5 tonnes of emissions with 1 tonne of softwood. Van der Lugt says of the new location of the Weener XL that ‘1995 tons’ have been saved in total. To further increase the impact of wooden construction and its awareness, a Manifesto 2.0 ‘Building within the limits of our planet’ is being fought to, among other things, establish a carbon budget for the construction sector, improve environmental performance. Systems and give bio-based materials a to give a better rating in Buildings’ Environmental Performance (MPG). “In the National Environmental Database (NMD), wood is not yet valued well enough,” says Van der Lugt. “The manifesto wants to ensure that the actual CO2storage is included in the calculation. CO2 storage is mentioned in all life cycle analyzes (LCA), but not yet included. If we do that, this will create a different, fairer playing field.” Van der Lugt adds that we need to pay more attention to health: “The possibilities are clear. Wood fits well into an environment designed based on biophilic design. People have the better there, recover faster in, for example, a care environment or perform better in a learning environment. The new construction of the Venlo Municipal Office shows that a healthy building can reduce sickness absence by 2 percent. And if you want to retain or attract employees for a long time, well-being is an important pillar.”

Bio-based construction is becoming commonplace

During the panel discussion, Niels Walters from Tarra arkitektur & urban planning makes it clear that this focus on health was an important part of the development of the new home for Weener XL: “We met at an early stage and thought about how we can create a healthy building. could make and with which materials. We quickly noticed that we had a shared vision and drive to design differently here, with wood.” Michael Bol from Bureau Kade adds: “For Weener XL, we set up the design in such a way that the building could be built in wood. We had been working with bio-based solutions for years, but we see that it is still common. There is still a lack of knowledge about this topic in the industry, which is why events like this are held [red: Natuurlijk, hout!] so valuable.”

'Wood is the solution to an existential problem in construction'

From left to right: Niels Walters, Rob van Gestel, Michael Bol

Role change

Rob van Gestel of Archimedes adds that circularity and sustainable construction will become the standard: “It is inevitable to reach our climate goals.” He also notices that timber construction is increasingly being chosen for construction contracts. “That is equivalent to half of the tasks.” Bert Verwoert from Alwiti Aluminum Geveltechniek and Jaap Kok from Laminated Timber Solutions agree. Verwoert: “We feel that there is more demand from the market. And it is challenging to coordinate the different variations in e.g. the facade.” Kok: “There are more and more good examples of wooden construction. I agree with the importance of shared responsibility. We are seeing a change in role because the producers are not throwing the wood over the fence, but are a closer part of the process. The integrated collaboration makes the process.” Walters concludes: “Using 100 percent wood is not the goal for Weener XL, but a smart, circular and healthy building that is possible. No waste, no downtime.”

Text: Marvin van Kempen, Image: Dura Vermeer

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