Nicholas Grimshaw and Partners' Eden Project in Cornwall is set to almost double in size under new plans being drawn up for the giant greenhouse development.
The £75 million botanical centre and visitor attraction currently consists of two giant steel frame greenhouses set in a disused clay quarry outside St.
Austell. These so-called 'biomes' are still under construction and will feature plants from warm temperate climates and the humid tropics. But they could soon be joined by new green houses for semi-arid and sub-tropical plants. This will depend largely on the centre hitting visitor targets of 500,000 a year, from the 2.5 million holidaymakers who visit the South West peninsula annually and the UK's three million enthusiastic amateur gardeners.
The extra developments could spell more work for the practice worth millions of pounds.
'We always left room in the masterplan for these additions and there could be two subsequent smaller biomes, ' said Jolyon Brewis, associate at Grimshaw's. The superstructure and cladding alone for the new elements would cost around £26 million, he estimated. Grimshaw is also in talks with the project's landscape architect, Land Use Consultants, to design a number of smaller pavilions within the biomes, he added.
The news came as the visitor centre for the Lottery-backed project opened to the public this week, in advance of the opening for the entire project around Easter 2001. The centre will allow visitors to view the construction of the 60m tall biomes and see an exhibition on the centre's goals.
Grimshaw has avoided using glass for the greenhouses and has instead opted to clad the steel frame buildings with almost transparent polygon-shaped air-filled cushions made from 0.2mm thick polymer known as ETFE. The alternative to glazing means that the load on the structure is reduced and that more light will penetrate the greenhouse. The material is intended to last at least 30 years but the choice has raised fears that the cushions will act as drums during rain showers.