Photo: the invisible part of fungi used for biobased building materials: mycelium


Jan Willem van de Groep: ‘You can build an entire house with biobased materials’

By: Jessica Merkens

Fifteen years ago, Jan Willem van de Groep read a book: The World is Flat by Thomas L. Friedman. From that point on, he knew for sure: this is not the path we should be taking. Ever since, the Dutch innovator and entrepreneur is committed to the transition of energy and materials. A conversation about building with biobased materials, carbon storage in houses and lobbying in construction industry.

Sustainability in construction

‘I engage in stimulating sustainability in the construction industry. On a national stage, I try to boost biobased construction and digitisation, particularly to speed up the sustainable transition in energy and materials. Ever since I graduated as a business and civil technician, I’ve been fascinated by innovation. How can you realise change? For the challenge of sustainability, innovation is incredibly important. The path we’re taking at the moment is not one that’s helpful for the next generation. I am continually looking to do things better, smarter and more sustainable.’


The usage of crops is on the rise

Building with crops and residue

‘When you’re talking about biobased construction, most people thing of wood. And rightfully so, it’s the most applied biobased material, even in traditional construction. What follows, are niche markets, such as straw, hemp, flax, cattail and bamboo: they are all crops one the rise. These materials are mainly applied in private houses, but not yet on a big scale. Besides crops, there is residue from agriculture and horticulture. Residue of tomato plants, the stems of bell peppers, products like that. You can increasingly use those as construction materials as well. Just like roadside grass that you can use for isolation.’ ‘In reality, all biological materials that have fiber, lignin and cellulose are suitable to make construction materials. It’s the basis. You can make a lot from these biopolymers. The market for biochemistry is growing. Biopolymers are increasingly going to be used for this.’

Jan Willem van de Groep

An entire house made with biobased materials

‘In theory, a complete house could be built with biobased materials. You already see this happening with very small houses. The foundation is more difficult, however. You mostly see that some form of concrete is used. But there’s creativity and innovation on that side as well. Such as steel screw piles, on which wooden beams are placed, upon which a wooden floor is attached. But in project-based construction, foundations will probably still consist of concrete. But then CO2-neutral, hopefully.’ ‘For construction, wood has the most potential as a material. There are thick, wooden panels from which you can make entire walls called cross laminated timber. For facades, you see more and more wooden skeletal construction walls filled with biological isolation materials being used. Panel materials are increasingly made from biobased materials. And biocomposites are also upcoming. Here, they are mainly looking at upgrading the life span of biobased raw materials.’ ‘Personally, I like the development around mycelium. Here, they grind residual waste and add spores from a mushroom-like fungus. The roots grow all the way through the residual waste. This creates a mycelium panel. You can also put it into a mould and create a product that is 100% plant-based. It has similar qualities as commonplace isolation materials. It’s still in an early stage of development, but it is incredibly promising for the construction industry.’

Lobbyists in construction industry

‘Lobbyists from CO2-intensive building materials like metal, concrete and ceramics are trying to make the transition happen as slowly as possible. These are traditional construction materials that will obviously get pushed aside in the process towards sustainability. They are professional lobbyists and they’re in any commission that can influence policy. It’s understandable. If I would get this much leeway, I would take advantage of it too. We need to stop this whole practice. Even though these industries are working hard on becoming more sustainable and CO2 neutral, we can simply calculate that despite all their efforts, we are not going to attain the climate goals. There are simply better alternatives. They should not hinder those alternatives.’


Lobbyists from the metal, concrete and ceramics industry are trying to make the change happen as slowly as possible.

Carbon storage in your home

‘Biobased materials are replacing CO2 intensive construction materials and they even store carbon. This is the biggest gain in using biobased materials. Plants absorb CO2 and through photosynthesis, the atoms get parted. Oxygen is released and the carbon is stored inside the plant. Carbon is the basic building block of all that exists. We get it from oil and gas as well, but it is also stored in living plants. If you harvest a plant and make it into a construction material, the carbon remains stored in the material. In 75 years, you can reuse the material. Or the biopolymers will be used in biochemistry. In that way, we can take a lot of CO2 out of the atmosphere and store it in construction materials.’

CO2 storage in the North Sea

‘The Dutch government has subsidised 2 billion euros to store CO2 in the bottom of the North Sea, in an empty gas field. For fifteen years, 2,5 megatons of CO2 per year will be stored. That’s the equivalent of 40.000 houses and we’re going to build 100.000 per year. You can guess what the value per house is. The same subsidized money can be put into boosting biobased construction. It has the same effect as storing CO2 in the bottom of a sea, but you are simultaneously solving the housing shortage and you are storing CO2 and you are minimizing the CO2 emission because you use less concrete, steel and ceramics.’

Architects have to catch up

‘As long as there are no laws and regulations, developers have to be as ambitious as possible if they want to add to the climate goals. Give your building criteria to comply to when it comes to CO2 emission and take carbon storage into consideration. I think architects have to catch up. Eighty percent of what they learn is based on ancient building principles. At school, too little attention is given to biobased construction. I get a lot of questions from architects working on big projects. I often match them with a colleague that has experience in biobased building. They are often surprised by the new insights they get from them.’

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