The Downland Gridshell has provided the Weald and Downland Open Air Museum with a more valuable building than the original brief of a workshop and artefacts store. Sunken into the ground, the archive level contents are protected from weather changes using minimal energy. The upper level provides a work space for the restoration and building of timber frames, but has also been used for a wide variety of events including educational activities, performances, festivals and a wedding. This landmark structure was created by an integrated and inspired team.The main space, the timber framing workshop, was built of very thin green oak laths bolted together to form a square lattice about 50m x 35m. The lattice was assembled and then bent, using gravity, into a shape resembling a three-nut peanut shell. It is the first building of this type ever built in Britain and only about the fourth in the world.The environmental impact of the building was the subject of a DTI research study by Buro Happold in October 2001. This study compared the green oak gridshell with steel and concrete alternatives, using BRE's ENVEST tool. The embodied eco-rating of the gridshell design has an impact of about 47% of the alternatives. The upper storey structural elements alone are about 3% of the alternatives.This is a relatively small project that has so far had a major impact upon a sparsely populated part of Britain. Since completion the public have travelled widely to see it. It has won a number of awards and in 2002 was a Stirling Prize finalist.