We were invited by the Science Museum to submit proposals for a new archive store on a former airfield at Wroughton, near Swindon to accommodate a large and varied collection of museum artefacts currently stored in London. These museum objects vary from small objects such as books to large vehicles and even planes. Many are being kept for historic purposes, but are rarely if ever displayed, only a few are stored temporarily, visitors are by special appointment only. A low maintenance, low energy, long life building solution is required. Stable temperature conditions and low humidity are required. A design which minimises risk of water ingress is essential as is a low cost solution. Our proposal was for a super-efficient, wide span timber arch structure capable of supporting heavy loads and creating flexible internal space. The absence of walls avoids junctions for potential leaks and reduces building wind loading. Heavy mass helps create a stable internal climate, with little energy load.