We created a bespoke arch structure for Engineers Create 2025, formed entirely from hempcrete blocks from The Hemp Block Company Limited, plywood chocks, and hemp rope. The shallow catenary form worked in pure compression, held in place only by rope tension, with no fixings or glue. It was built successfully and stood freely several times before and during the exhibition set up.

On the night of the launch, our Director decided to test its limits, and found them. The structure collapsed, and trying to rebuild it taught us more than we expected.

Small imperfections from the collapse made it far more sensitive to movement and load. The hempcrete blocks, though similar in size, varied just enough to create tiny hinges between units. With a bit of stretch in the rope, these tolerances reduced the stability that compression structures rely on.

The collapse became part of the experiment. Each rebuild revealed more about how natural, low-strength materials behave structurally and where their limits sit.

Next time, we’ll refine both the geometry and the materials to make the structure more resilient and quicker to put back together, including selecting the most uniform blocks, finding better ways to maintain rope tension, increasing chock size, considering cast hemp, and designing bespoke formwork and stronger supports.

Engineers Create, organised by The Engineering Club, filled Candid Arts Trust in London with models, drawings, prototypes, and material experiments from engineers and designers. The exhibition ran until 15 November.