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Construction farmers harvest the first 18 houses in the country

By: André Oerlemans
The Bouwboeren have harvested the first eighteen houses in the country in Central Netherlands. Well, houses. Insulation material for eighteen houses. They will soon also use it to make building materials and eventually build bio-based homes. “We want to close the entire chain per region.”
More and more project developers and contractors are switching to biobased construction. Only by finding alternatives to concrete, steel and cement can the construction sector sufficiently reduce its CO2 emissions. In his letter to parliament last December, Minister Hugo de Jonge (Public Housing and Spatial Planning) announced that he will stimulate the cultivation of fibers as a raw material for building materials. In the spring, the government allocated 200 million euros from the Climate Fund for this purpose.

Trial harvest
These biobased materials must come from forest managers and farmers, such as the Bouwboeren from Houten. As circular project developers and architects, initiators Luc and Wout de Wit could hardly find biobased materials, so they decided in 2021 to grow them themselves. They also wanted to offer farmers an alternative revenue model. 2023 is a test harvest year for construction farmers. This spring, six farmers from the Utrecht and West Betuwe region sowed a total of eight fields with five crops: elephant grass, sunflower, two types of sorghum and fiber hemp. They grow well without fertilizer or pesticides. A total of 25 hectares was sown. Next year that will be 100 hectares. Three new farmers have also already registered.
Complex year
The first year was a complex year, says construction farmer Luc de Wit. “We had an extremely wet spring, followed by an extreme drought. Nevertheless, the fields, except for one hemp field, developed well,” he says. “After that, in August there turned out to be no suitable harvesting machine available and the harvest had to be postponed three times.” Finally, a harvester arrived from Groningen at the end of September, after which the crops were able to dry in the fields for another two weeks because of the nice weather. "The yield this year was slightly less than expected, but this is a lesson for next year. That is why we are looking at whether we can purchase such a harvesting machine together with the farmers or contractors ourselves," says De Wit.
50,000 products
The proceeds can be used to make enough blow-in insulation for eighteen sustainable houses. That doesn't happen automatically. De Bouwboeren have developed a mobile factory that produces usable semi-finished products on site in the fields of agricultural crops. The farmers founded the Biobased Factory for this purpose. In three weeks' time, the mobile processing plant will process stored bales of fibrous crops into biobased fibers, woody parts or green microfibers for the first time. This can be used to make building panels or insulation material. All building materials for construction, industry and logistics. “You can make more than 50,000 products with our semi-finished products,” says De Wit. “Next year we will work with TNO and Wageningen University to see what else we can make with the Biobased Factory.”

The first harvest is processed into blown-in insulation. Initial, unofficial fire tests show that it takes more than two hours for this material to burn through. "After that we stopped testing," he says. The argument from critics that bio-based materials would make houses more fire-hazard seems to have been rejected.
Biobased homes
Once the Biobased Factory is running sufficiently and has been scaled up, the Construction Farmers want to take the next step: building houses from biobased materials. To this end, they founded the company Biobased Housing Solutions, so that the cycle from seed to home is complete. These homes will have a skeleton of wood and insulation material from the land. The first biobased houses were announced this year during Provada: Beehome. In addition to being biobased, the homes are also CO2 negative and absorb 50 tons of CO2 more per home than they emit during the entire production process. Wout de Wit: "We are in the final phase of the engineering. Building biobased houses is the logical next step in the entire process. We want to close the regional chain.”


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