Biochar concrete opens up prospects for a climate-neutral construction industry
Ulrich Imboden AG, Logbau, Novakies and Toggenburger have founded KLARK AG. Together, they want to make a concrete available throughout Switzerland that is CO2-neutral thanks to the use of biochar. The aim is to turn buildings and infrastructure into CO2 sinks.
Four construction companies from Switzerland have joined forces to found KLARK AG, based in Landquart GR, on 25 August 2025: Ulrich Imboden AG from Visp VS, Logbau AG from Maienfeld GR, Novakies AG from Rapperswil BE and Toggenburger AG from Winterthur. Their common goal is to make KLARK concrete, which is CO2-neutral thanks to the addition of biochar, available throughout the country.
In a press release, they describe the founding of KLARK AG as a milestone for the Swiss construction industry: “It shows that ecological responsibility, economic thinking and cooperative structures can go hand in hand – even and especially in an industry that has long been considered sluggish.” KLARK stands for a move towards a building materials market “that not only measures climate effects, but actively changes them”. This is “industry innovation instead of individual battles”.
The KLARK climate clay is mixed with as much biochar from untreated waste wood from regional forestry until a CO2-neutral product is created. According to the information provided, it has the same properties as traditional concrete, which causes CO2 emissions of up to 250 kilograms per cubic metre.
The CO2 reduction performance has been verified with a verified life cycle assessment in accordance with the accounting rules of the Coordination Conference of Building and Property Bodies of Public Building Owners(KBOB). The life cycle assessment results are published on the KBOB list. KLARK concrete can be produced with 50, 75 or 100 per cent sink rate and is fully recyclable.
Eberhard Bau AG from Kloten ZH, Aarebeton Aarau AG and Arnold & Co. AG Sand- und Kieswerke from Flüelen UR are already on board as licence holders for the production of KLARK concrete. “This creates a central competence centre for CO2-saving construction with concrete, supported by regional pioneers with a national reach,” the press release states.