Scientists from ETH Zurich, Empa, and the Polytechnic University of Turin have demonstrated that sawdust, when bound with struvite—a crystalline ammonium magnesium phosphate—can be transformed into lightweight, flame-resistant building panels. Struvite is already known for its fire-retardant qualities, but its brittleness has long limited practical use. The breakthrough came when researchers used an enzyme derived from watermelon seeds to control how struvite crystallizes. Instead of forming weak bonds, the mineral grew into large crystals that filled cavities between spruce sawdust particles, locking them together with remarkable strength.

Sawdust, once dismissed as waste, has now been pressed into panels that outperform spruce timber in compression tests and resist fire as effectively as cement-bonded boards.


The process begins with newberyite, a precursor mineral suspended in water. With the enzyme guiding crystallization, struvite forms in a way that integrates seamlessly with sawdust. The mixture is pressed into slabs for two days, then dried at room temperature. The resulting panels not only withstand compression better than spruce timber but also exhibit impressive fire resistance. When exposed to heat, struvite decomposes, releasing water vapor and ammonia. This reaction absorbs heat, cools the surrounding material, and produces non-combustible gases that displace oxygen, starving flames and slowing their spread. The panels char quickly, reducing flammability further.

Initial fire tests suggest these panels match the protective performance of cement-bonded particleboards, yet they are significantly lighter. That difference matters in construction, where weight reduction can lower costs and simplify installation. Beyond performance, the panels offer a sustainability advantage. Cement boards are typically discarded after demolition, but struvite-sawdust panels can be recycled. The process involves grinding, heating to 100 °C, and separating sawdust from the mineral, which can then be reused to form new panels. This circularity aligns with growing demands for materials that minimize waste and environmental impact.

Ronny Kürsteiner, a doctoral researcher at ETH Zurich who led the study, emphasized the dual benefit of strength and fire resistance. “We were able to show that sawdust, usually considered waste, can be turned into a high-performance material when combined with struvite under controlled crystallization,” he explained. His team’s findings were published in Chem Circularity in March 2026, underscoring the potential for practical adoption in building design.

The implications extend beyond laboratory success. Forestry and lumber industries generate vast amounts of sawdust, much of which is burned or sent to landfills. Redirecting this waste into construction materials could reduce emissions and create value from an overlooked resource. Meanwhile, struvite is abundant and inexpensive, often encountered as an unwanted deposit in wastewater systems or even as kidney stones. Harnessing it for construction turns a nuisance into an asset.

The panels’ performance under compression perpendicular to the grain is particularly notable. Traditional timber weakens under such stress, but the struvite-sawdust composite proved stronger, suggesting applications in internal partitions and other load-bearing structures. Fire safety is another critical dimension. By releasing gases that suppress combustion, the panels provide passive protection without relying on chemical coatings or additives that may degrade over time.

The research team acknowledges that scaling production will require further testing, particularly under real-world conditions. Moisture resistance, long-term durability, and cost competitiveness must be validated before widespread adoption. Yet the promise is clear: a material that is lighter than cement boards, stronger than spruce timber, and recyclable at the end of its life cycle.

If construction embraces this innovation, buildings could one day be lined with panels made from what was once discarded sawdust, bound by a mineral more familiar in medical textbooks than in architecture. The story of struvite and sawdust is not just about fire resistance—it is about reimagining waste as a foundation for safer, lighter, and more sustainable structures.