SOWING THE FUTURE.

The barrel-vaulted form of a major new seed bank for the Royal Botanical Gardens melds almost organically with the undulating Sussex landscape.

The Wellcome Trust Millennium Building, by Stanton Williams, is a new seed bank for the Royal Botanic Gardens of Kew. Due to be finished in the autumn, it is being built in the grounds of an offshoot of Kew: Wakehurst Place, Ardingly, Sussex. When completed, the building will hold the largest collection of seeds in the world, including the seeds of thousands of endangered plants.

The site in the High Weald is on a spur overlooking the Loder Valley in an area of outstanding natural beauty. Planning dictates were therefore strong. Responding to these and to the character of the wide-open, rolling landscape, the architects conceived a series of templates, simple vaulted buildings measuring 14.4m x 7.2m and linked by primary and secondary circulation routes.

All of the main process and research laboratories, and public areas, are above ground on one level, with the scientific buildings aligned east-west and disposed in two groups of six each side of a glazed winter garden. From within this area, the public will have direct views into the laboratories and be informed by video about scientific processes. North-west of these buildings is a sunken courtyard and research glasshouse. The courtyard is the focus for academic facilities and study bedrooms, providing a quiet collegiate atmosphere as well as private retreat for both staff and visiting scientists.

Seed storage requires sub-zero temperatures (seeds can be kept in a state of suspended animation for 200 years or more). Underneath the main block of laboratories, the seed bank here is a secure underground chamber kept at very low temperatures and the right humidity. Main materials are concrete, York stone, painted steel and structural glass panels. Fixing details are articulated in stainless steel. Concrete barrel-vaulted roofs over laboratories and fair-faced concrete walls provide the thermal mass necessary for the naturally ventilated laboratories. In contrast, a layered steel and glass barrel-vaulted roof is suspended between the scientific buildings to create the shaded public winter garden.