In summer 2025, the Earth Build Project team spent 11 intensive weeks generating more than 200 small-scale samples for testing in Cardiff University’s Duralab. It was hard graft and we faced daily challenges, but with the determination and dedication of the whole team, ably led by Megan, we were able to successfully print over 200 cubes, cylinders and prisms to the specified size required for the lab testing equipment.
The structural and thermal benefits of adding straw to an earth mix are widely known here in the UK, where we have a long tradition of using cob for construction. But this summer explored more widely, trialling hemp shiv, cellulose (a natural insulation product made from recycled newspapers), and sheep’s wool in addition to straw.
All of our samples are being tested for compressive, tensile and sheer strength; thermal conductivity and their capacity to withstand freeze-thaw conditions, replicating the UK’s climate. The results will inform our ongoing research; we’ll be moving forward with the most promising mix/mixes in 2026, and trialling other bio-materials for enhanced performance, including resistance to cracking and shrinkage.
