The Coalymer Stool has a negative CO2 footprint: It binds more CO2 than is released during its manufacture. It is based on an innovative mixture of cement-free geopolymer and CO2-absorbing biochar. Generative design, 3D printing and a digital workflow result in a resource-saving, climate-friendly and high-quality piece of furniture.

The geopolymer concrete consumes 80 per cent less energy and CO2 than conventional cement concrete and still remains resistant. The integrated biochar permanently stores CO2, making the Coalymer Stool climate-positive. Even after repeated recycling, the material remains usable and stores CO2.

The biopolymer mould is manufactured using 3D printing, separated by type and reused several times. It enables a lightweight, efficient design with complex openings - a first in the concrete furniture sector. Recycled plastics can be used as an alternative.
Our contribution sets new standards for sustainable innovation: the Coalymer Stool brings sustainable design to life and promotes climate-conscious behaviour. The combination of geopolymer, biochar and 3D printing technology offers a scalable model for future concrete components with a low carbon footprint.
According to the UN, biochar is the key to achieving the SDGs. CO2 certificates (CORCs) prove its effectiveness. The Coalymer Stool shows how pioneering materials and digital manufacturing enable a circular economy.