Can food waste be repurposed into building materials? This question was at the heart of Lara Neuhaus’ graduation project Bio-composites from food waste at TU Delft. In her work, Neuhaus developed a promising biocomposite material made from walnut shells, aiming to explore more sustainable and circular solutions for the construction industry.

The initial results are promising: a rain-resistant façade panel created from agricultural and food production by-products. The project demonstrates how valuing imperfection—in colour, texture, and composition—can lead to new material narratives and encourage designers to rethink aesthetics and performance.

Biobased Composite from Waste Streams
Neuhaus combined various organic waste materials to form a pressable sheet material suitable for exterior cladding. The first prototypes were made with walnut shells, coffee grounds, cocoa husks, and linseed press cake—each tested for durability, water resistance, and structural strength.

Among these, the walnut shell composite stood out for its processability and robustness. Its hardness and structural integrity make it well-suited for façade applications, where resistance to weather and impact are crucial.

Moulding, Mixing, and Pressing
The material was tested in different forms—powder, granules, and flakes—to assess its behaviour in pressing and forming. Walnut shells were particularly suitable for mixing with various biobased binders and forming under pressure. During trials, hydraulic pressing at 150 degrees Celsius and pressures up to 55 bar proved most effective.

The production process included detailed testing of moisture resistance and durability. While the material is not yet suitable for load-bearing uses, its properties suggest strong potential for architectural cladding, furniture surfaces, and even interior wall finishes.

Sustainable and Circular Potential
One of the standout features of this biocomposite is its low environmental impact. Unlike traditional synthetic or mineral-based materials, it’s made entirely from organic waste, offering significant CO₂ savings. The material has a relatively low environmental footprint and could contribute to a more circular building practice.

Embracing Imperfection
Neuhaus advocates for a shift in design thinking—one that embraces the irregularities and “flaws” of natural materials. In her view, aesthetic perfection is less important than environmental performance and storytelling. Designers who adopt this mindset may find not only new materials, but new values to design with.

Her project received the Winner Circularity in the Built Environment Graduation Awards 2023–2024 in the category Materials & Components from the Circular Built Environment Hub at TU Delft.

Source: TU Delft
Photo via TU Delft