Biochar, as we know,is made by heating biomass to a temperature of 400 to 800 degree Celsius in the absence of oxygen. This process used is called pyrolysis. The resultant material is characterised by high specific surfaces of more than 300 m2 per gram, distributed over countless nano, micro and mesopores. The ability of these pores to store water makes biochar a very efficient medium for storing moisture. Additionally, the pores trap large quantities of technically immobile air, therefore making biochar is one of the best insulation materials known to humans. Biochar has extreme low thermal conductivity and can absorb water 5 times its weight. Now, what does all these technicalities imply? That it can be an excellent building material.

There has been substantial research on this and has yielded stellar results, and now, biochar infused architecture is making its presence felt at multiple places across the globe.

In Australia, researchers at Victoria University integrated coffee waste-derived biochar into concrete for use in sidewalks and structural trial components. The biochar was blended into cementitious mixes at replacement levels ranging from 0.5% to 1.5% by weight. This real-world deployment followed promising lab results showing that the addition of biochar significantly increased compressive strength by up to 29%, reduced water permeability, and contributed to overall sustainability through carbon sequestration. The biochar used had a typical chemical composition of around 72% carbon, 16% oxygen, with minor elements like potassium (3.5%), phosphorus, and calcium, depending on the pyrolysis conditions. This project marked one of the first transitions of coffee biochar from lab to field in concrete construction.

Again, in a collaborative project, Spain and Thailand used biochar produced from gasified olive stones to stabilise weak subgrade soils for road construction using geopolymer technology. The biochar was treated with alkaline activators and incorporated into road base layers tested under simulated traffic loads and real climate exposure. The resulting material exhibited high load-bearing capacity, improved freeze-thaw durability, and reduced deformation. The biochar contained 75–85% carbon, about 10% oxygen, and trace minerals including alumina, silica, and iron, essential for geopolymer reactions. This initiative is a stellar example of how agricultural waste can be transformed into high-performance, carbon-negative infrastructure material.

In South Korea, biochar was used as a functional coating on Medium-Density Fiberboard (MDF) to enhance fire resistance in interior architecture and public furniture. The boards were coated with a mixture of biochar and expandable graphite, resulting in a composite with substantially improved flame retardancy, lower smoke release, and better thermal stability. Laboratory tests confirmed that the addition of 10% biochar helped delay ignition and reduce heat release rates during fire exposure. The biochar used for the coating typically contained 80% carbon, around 8% hydrogen, and varying traces of silicon, magnesium, and calcium, depending on the biomass origin. This shows the role of biochar in passive fire safety for buildings.

In Poland, researchers applied biochar to enhance hempcrete wall systems in low-energy and sustainable housing prototypes. Hempcrete, a composite of hemp shives and lime, was mixed with biochar at 5–10% volume ratios to improve material performance. The inclusion of biochar led to a 35% reduction in water absorption, improved thermal insulation, and a more porous structure that facilitated CO₂ sequestration. Biochar sourced from woody biomass typically exhibited 70–85% carbon, with low ash content and trace potassium, calcium, and silica, all contributing to the improved hygroscopic and thermal properties of the hempcrete. These biochar-enhanced panels were deployed in real buildings designed for environmental certification trials.

Looks like biochar is building the buildings of the future, one pore at a time.