The Big Build

Restoring an Industrial Wasteland

The Project features two spectacular giant biomes, surrounded by the developing outdoor landscape of gardens. The project has been created in an abandoned clay pit on the outskirts of St. Austell in Cornwall. The original pit was some 60m deep, a gaping eyesore created by the extraction of minerals for the local china clay industry.

Although the site covered an area of 35 football pitches, the building contractors had to remove a further 1.8 million tonnes of material, in a process that took 12 trucks and 8 bulldozers, six months to complete. Once the problems of drainage (43 million gallons of water during the first three months alone) and the sides of the clay pit had been stabilised, the problems of creating the world's largest greenhouse began.

Creating The World's Largest Geodesic Conservatory

The Eden Project has the largest geodesic lean-to conservatories in the world. The Humid Tropics Biome is 240m long, 110m wide and 55m high. During the construction of the biomes, another record was set, as the project needed the world's largest freestanding scaffold.

The Eden Project brought together a world-class team in 1995. The team was set the task of creating a spectacular architectural showcase that would match Eden's horticultural ambitions. Simply to, create an international showcase for the study of human dependence on plants.

The designs involved turning a 50 metre deep, 15 hectare china clay pit, overlooking St. Austell Bay in Cornwall into a dramatic landscaped paradise that would house thousands of important and beautiful plants from three climatic zones in the world; a temperate climate and, housed in two giant conservatories, the humid tropics and warm temperate regions.

In addition to this mammoth task, the grounds needed to contain a Visitor Centre, classrooms, an exhibition gallery, conferencing facilities, an amphitheatre and lake, and assorted catering and retail facilities containing plant products from all round the world.

The biomes are constructed from 625 hexagonal windows, the largest one measuring 11m across. Glass could not be used in the construction as the weight would be far too great for the frame to support, and there would be a very severe safety hazard.

ETFE -'Cling film with attitude'

The Eden Project is run by a charitable scientific organisation, Which holds a deeply rooted commitment to communicate, educate, entertain and involve the public in the pursuit of its mission, both at Eden the destination and with partners outside.

The problem was solved by the use of ETFE (ethylenetetrafluoroethylene), known affectionately on site as ' cling film with attitude'. Each of the dome's hexagons is made up of three layers of the transparent ETFE foil. The hexagons are inflated to create 2m deep pillows that are then used to clad the exterior of the structure.

ETFE has all the qualities needed for this kind of project, it is transparent, weighs less than 1% of the equivalent sized pane of glass, is safer in use and has non stick properties, making it self cleaning. The finished geodesic domes weigh only slightly more than the mass of air that they contain.