Photo via Jan Willem van de Groep
Technology is not the bottleneck in the transition to a sustainable built environment. In addition, it is essential that the bio-based materials are not cycled into the project later, says sustainable construction expert Jan Willem van de Groep. Raw materials such as wood, hemp and straw are only an economically attractive alternative to the more traditional steel and concrete if you start from them from the start.
This article was previously on the website of the housing development study Almere
Jan Willem van de Groep is an old hand in a relatively new industry. For more than a decade, he has worked tirelessly on a more sustainable building environment. It operates at the forefront of construction, housing, agriculture and energy and was one of the founders of Stroomsnel, Factory Zero and Gideons Tribe, among others.
In addition, he often works with governments, from central to provincial to municipal. For example, together with transition strategist Atto Harsta, the Almere Practice and Innovation Center for Circular Economy (PRICE) and Boligbyggeri Atelier Almere, he has organized the webinar series Biobased Bites, about the current situation within bio-based construction.
What are the most striking conclusions from the bio-based bites?
“We have dealt with many different systems and materials. WikiHouse, wood, hemp, mycelium, biocomposites. It shows that much is already possible in sustainable construction. The Nature Pavilion on the Floriadeterrein has also contributed to this in the past year.’
“Many connections were also made between entrepreneurs and other actors during the sessions. That surprised me. One would expect the bio-based world to meet regularly, but in practice it is disappointing. Entrepreneurs are primarily concerned with developing their own products and have less time to make connections.’
‘At Biobased Bites, people often lingered for a long time. For example, we had an entrepreneur who makes hemp insulation and an entrepreneur who needs hemp disc. The crooked ones are a residual product from the insulation, so a collaboration is created.’
When talking about bio-based construction, people often think of wood first. What are lesser-known materials that deserve a little more attention?
‘You can use yesterday’s most promising materials, so to speak. Hemp, flax and straw are therefore promising in the short term. In the longer term, biocomposites will play a major role as a substitute for steel and concrete. It’s still in its infancy, but it’s promising.’
“There are also opportunities for fibers from crops that absorb a lot of CO2, such as elephant grass, sunflowers and sorghum. You can easily grow these in the Netherlands, which is already being done for other purposes. So making building materials out of it, that’s really it Next step.’
Technically, a lot is already possible and there is a lot of innovation. At the same time, we see that the demand for bio-based materials is not always there. How do you fix it?
“I am very much in favor of solutions where you do not artificially create demand. Bio-based materials must be priced at such a level that they independently become an attractive alternative to traditional materials. Prices are already close to each other, especially in light of current energy prices and rising construction costs. So now it’s about achieving scale so that prices fall somewhat, and bio-based materials are a logical option in the construction industry.’
It sounds like a chicken-and-egg kind of thing. Lower prices require scale, but scale requires lower prices.
“There really must be a latent need to get that increase in demand. Customers must steer towards this and they must be prepared to invest in it. Besides, the gap really isn’t that big.’
»Take insulation, for example. Not much insulation material is used in the average home, so using hemp bio-based insulation instead of rock wool saves a few hundred euros per year. Most companies can and will suffer from this. The quality of the hemp is also many times greater, it is a higher quality product. But that value is not always correctly estimated.’
Do you expect that the Council of State’s repeal of the nitrogen exemption for construction will give the necessary impetus to the issue?
‘That might help. Wood and other bio-based materials are lighter than traditional ones. You therefore need less heavy equipment for construction, which means less nitrogen emissions. That makes it part of the solution.’
“But I don’t see any major changes yet. It will take a few more years. It is not easy to manage a construction project. You can’t just convert all the buildings that are now getting permission to be bio-based. Because the qualities of the bio-based materials were not taken into account right from the start of the design.’
“For a good business case, it is important that you focus on bio-based from day one. If you design old-fashioned and want to replace steel with, for example, wood, it will be very expensive. Then you do not make optimal use of the properties of wood and other bio-based materials. But if you think in terms of these materials from the start, the difference is not so small. Then you start dimensioning differently, you need less material, and all in all you do it much more intelligently and more affordably.’
Many examples of bio-based construction are with low building heights and densities. While the governments focus a lot on inner city development. What role can bio-based construction play in metropolitan areas?
“Bio-based materials are not particularly suitable for real high-rise buildings. Tall towers still require a lot of innovation and development. Bio-based insulation and facade treatment are somewhat unfortunate in combination with high-rise buildings, due to the fire requirements. Sound is also a challenge.’
‘But forget towers, take wood as a starting point for the design. What bio-based materials are very suitable for: building up to sixty meters. Ten floors are really easy to save with tree core modules. This also fits perfectly with the densification ambitions of many cities. Little C in Rotterdam, for example, could easily have been built with wood. That complex has the same density as Zalmhaventoren.’
‘You have to revise the urban planning principles. Welfare notes, for example, are not geared towards bio-based materials at all. They are all based on bricks and have an idiom that does not fit biobased. We must therefore agree with each other that we really start from wood and other bio-based materials and design accordingly. With different densities and no more tall towers. That is the consequence of that carbon based design.’