Sheep wool and seaweed alginate strengthen unfired clay bricks, cutting the carbon cost of construction

Researchers mixed sheep wool and alginate, a polymer from brown seaweed, into clay soil and let the blocks air-dry instead of firing them. In lab tests, adding wool fibre raised compressive strength by 37 percent, and combining wool with alginate roughly doubled the untreated soil's compressive resistance. The aim is to offer a low-carbon alternative to kiln-fired bricks and cement-stabilized earth, two building methods with heavy carbon footprints. These are early lab results, not a finished building product. Fired clay brick production is estimated at around 1.1 gigatonnes of CO2 per year, and cement accounts for about 8 percent of global emissions. Wool and alginate are close to waste streams, but unfired earth still needs to prove itself on moisture, weathering, and durability before building codes accept it. For now, this is a promising direction for low-carbon construction, not a ready replacement.