Biobased building materials with proven low environmental impact

For building in The Netherlands you often needs an environmental permit. The application for this permit includes an environmental performance calculation. Contractors and architects use this calculation to demonstrate the environmental impact of the building materials they intend to use. To perform this calculation, they need data about these materials. How long will the material last? How environmentally friendly is its production? Can it be reused effectively? This information is stored in the National Environmental Database (NMD). At least, that's the intention, but currently the database lacks some of the information companies need.

Demonstrating the low environmental impact of biobased building materials isn't always easy. "Many of these materials are relatively new," says Martien van den Oever, biobased materials researcher at WUR. "They were often developed by smaller companies that were less concerned with disclosing their environmental impact." The researchers therefore helped thirteen biobased materials enter the database by providing them with a life cycle assessment (LCA). "This was a real need of policymakers, architects, and contractors," says Van den Oever. After all, they need concrete data and values ​​to make decisions.

At the request of the NMD, the researchers also added a new calculation to the database. This allows a simple formula to calculate how much carbon a material has stored. A wooden beam or bioconcrete made from elephant grass is made up of plant fibers. These fibers formed because the plant absorbed CO₂ as it grew and converted it into tissues. This process is called biogenic carbon sequestration. "During the lifespan of these types of biobased building materials, there is therefore less CO₂ in the air," explains Van den Oever. This led to distortion: conventional materials sometimes appeared equivalent to biobased alternatives in the database, while in reality they release more carbon dioxide into the atmosphere and biogenic sequestration does not occur. Now, the comparison can be made more effective on that point.

Environmental performance calculations then revealed the potential difference between conventional and biobased construction. The researchers compared three types of homes: a terraced house, a semi-detached house, and an apartment. Each house was identical, but constructed from different materials. The construction activities were also the same, as were standard elements like electrical wiring. In this case, a biobased house appears to have an 18 to 35 percent lower environmental impact. "But without all those standard elements, the impact would be even higher. The materials make the difference," says Van de Oever. Moreover, there are indirect benefits. "For example, if you build the foundation with a lighter material than concrete, that also reduces the environmental impact of transport."

Together with Delft University of Technology, the researchers investigated whether building with biobased materials is also suitable for tall buildings. It appears to be possible, but not for the very highest apartment buildings. Van den Oever: "Such buildings have a concrete column in the middle that supports the floors. Since wood is naturally less strong than concrete, a wooden column needs to be thicker." There's a limit to this, of course. "Building with wood above sixty meters results in excessive material use. However, architects can replace some of the steel or concrete in the structure with wood. This still results in a reduction in CO₂ emissions."  

Wageningen University & Research collaborates with companies such as Soprema (roofing), Stora Enso (packaging, biomaterials, timber construction), and IKEA, and with government bodies such as the Municipality of Deventer, to develop biobased materials.

Wageningen University & Research provides evidence-based environmental performance data and calculation models for biobased building materials, makes them available in the National Environmental Database. We also demonstrate their CO₂ benefits. This allows companies to validate new materials, comply with stricter regulations, justify investments, and remain competitive while replacing fossil fuels.