‘Wood is our new building block: a perfect match’

It is almost lunch time when Wim enters the city center of Oirschot. Suppliers of shops and restaurants drive back and forth, the terraces are packed. Where will he be parking  his car? There is space around the corner, but his car can only stay there for one hour. His choice therefore falls on a parking lot, a short walk from his destination.

“This search for a parking space is very interesting,” he says. “Parking garages can make the streets look completely different, so that you can walk around. It is a way of getting a clear view of the children playing on the street. And it is a way of directing behaviour, as we see here in Oirschot. If I have to pay a lot of money to park my car in the city center, or if I can only park there for a short time, I prefer to park a little further away. And that is probably exactly what the intention of the municipality was.”

The combination of technology with behavioral psychology has already stolen his heart years ago. During his career he became increasingly fascinated by sustainable construction. Since then, within Ballast Nedam Park & ​​Connect, he has focused on realizing a fully circular living environment in the form of high-quality links in mobility, such as parking garages, bridges and viaducts.

It is not to be missed that you are fascinated by parking garages, bridges and viaducts in relation to demountable construction. But wood makes your heart beat even faster. Why is that?
"Correct. Wood offers so many opportunities. It stores CO2 and we also need fewer trucks, concrete mixers and less heavy cranes during construction, which means we emit less nitrogen. Just like with prefab concrete, we can already build elements of our bridges or parking garages in the factory and then assemble them on site like Lego bricks. A difference with concrete: because it is many times lighter, we can transport it more easily and efficiently, with more parts in one trip. This allows us to work even more safely. Because it is lighter, it needs a less heavy foundation, which saves us material. And during construction, processing wood makes much less noise than processing steel or concrete. That also makes it more attractive for the neighbors of our construction sites.”

We have already made many parking garages with wood. Mission accomplished?
“It's definitely a great start. At the P+R site in Dieren we worked with wood in the facade. At the parking garage of the Antonie van Leeuwenhoek hospital we worked with bamboo. And for the parking garage at Amersfoort Zoo, we had to cut down trees to be able to build the parking garage on that spot, but we literally returned the wood from that forest into the facade. For example, CO2 is stored in the facade and the project fits in with its environment. Those are very nice examples that make me very happy. But now it's time to challenge ourselves and our customers. Let's really start building with wood.”

At Ballast Nedam you are one of the challengers in this area. How do you challenge the rest?
“Sustainability is already a top priority for Ballast Nedam and our customers. But in the field of demountable construction, we can challenge our customers even further. We can dismantle a parking garage and put it somewhere else. No less than 96% of such a garage is then reusable. So it is actually a second-hand car: a beautiful example of sustainability. There are still many opportunities for our customers.”

“The construction industry is increasingly working with 3D printers. We can also use wood for this. With bio-composite consisting of wooden fibers with glue, we can produce custom-made elements. Does an element need to be replaced during maintenance? Then you print a new one. The old copy forms the raw material for another element. This fits exactly with our thinking.”

This wooden Stönner-Meijwaard bridge in Oirschot was one of our projects completed in 2020. How do you feel about standing here?
"'Respect' is what I feel. With this bridge we show respect for the environment, because on the one hand this bridge stores a large amount of CO2 during its lifespan and because it stimulates clean modes of transport such as cycling and walking. In addition, we honor two Dutch soldiers of the Princes Irene Brigade who died here during the liberation of the Netherlands through the name of this bridge. They fought for the freedom of future generations. Now it is up to us to 'fight' in our free country for a liveable world. Given the signals that the earth gives off, such as heat, drought, rising sea levels and flooding due to extreme rainfall, it is high time."

How do these projects stay safe if a fire breaks out somewhere?
“Many people do indeed think that such a wooden bridge or parking garage is a fire hazard. But wood is very predictable, so we know exactly how this raw material behaves during a fire. A reinforced floor or beam is a lot less predictable if a fire breaks out. That can suddenly collapse.”

“Before construction, we calculate the wood thickness we need for the construction. We also calculate the wood thickness required for fire safety. We add this extra thickness to the construction. One of the advantages: when a piece of wood is burned, it chars. This protects the underlying wood. So, although we need more material to make it fireproof, we also store more CO2 as a result.

How do you envision the use of wood in the future?
“I think we can replace concrete with wood even more often in future projects. We are working smarter all the time. For example, we used to take a tree trunk and make it into a beam that had a certain capacity. But such a beam can take a lot more weight if you saw it into planks and keep turning them over and gluing them together. Examples of these materials are CLT, Glulam and LVL. A tree trunk suddenly becomes very strong. This way you can achieve a lot more with inferior wood.”

“Ballast Nedam Park & ​​Connect focuses on circular construction with industrially made building blocks that can be reused indefinitely. And wood is a sustainable raw material that grows again and again and retains CO2. It is very easy to edit for a next function. A perfect match, where we want to use the benefits as smartly as possible. Wood is one of our new high-quality and reusable building blocks.”