Evolution House at the Royal Botanic Gardens, Kew

Evolution House at the Royal Botanic Gardens, Kew

A glasshouse built as the Australian House and opened in 1952, designed by SL Rothwell of the Chief Architects Division of the Ministry of Works, with consultant engineer JE Temple and constructed by The Crittall Manufacturing Co Ltd. The building was a gift from the Australian Government, following a visit to Australia by Edward Salisbury, Director of Kew Gardens. It was constructed to house plants collected by Captain McEachern from the extremely dry climate of south-west Australia, which had previously been stored in the Temperate House. Since 1995 the building has housed the Evolution exhibition, which charts the evolution of plants.

The Evolution House is constructed of a pre-formed galvanised frame in H10-WP aluminium alloy, set on a plinth of reused London stock bricks capped with a slate cill course. The mortar is flecked with coarse-grained grit.

The building is rectangular on plan with a mansard roof. The glasshouse is of 10 bays, measuring 90 feet by 52 feet and 33 feet 6 inches in height, covering an area of 4,680 square feet. The structure uses approximately 60 tons of aluminium alloy. The main frame consists of eleven arches of lattice construction, with 8-inch by 4-inch uprights and angle purlins. The end bays are braced, and the glazed curtain wall is bolted to the frame and uses standard window sections. The building is ventilated with horizontally opening side windows and clerestorey windows operated by a crank. Entrances in the end walls have moulded architraves, a detail which extends beyond the purely functional. Special facilities were provided for cleaning, using a spray system internally and with rails to attach ladders externally.

The glasshouse sits to the west of the Temperate House, aligned on its short east-west axis and the entrance to Kew Gardens to the east, which was originally intended to align with the proposed site for Kew Gardens railway station. The Australian House was the largest glasshouse to be built at Kew after the Temperate House and is one of a sequence of significant glasshouses at the Gardens.

Aluminium was particularly useful to horticulture, noted for its light weight and resistance to corrosion. The annual report of the Agricultural and Horticultural Research Station for 1948 referred to two small aluminium greenhouses completed that year for work on radio-active tracer elements and growth regulating substances, while in 1950 Gardening Illustrated advertised Crittall Rustless Greenhouses. Aluminium was used for whole buildings only after 1945, making this an early and rare example of an aluminium glasshouse of this period and of this scale.

The Australian House is cited as an exemplar, alongside the roof structure of the Botanical Gardens Conservatory in Washington, DC, in contemporary journals including The Aluminium Development Association (1953) and Brimelow (1957). Prior to its completion, it received a write-up in the National Builder (1951). It anticipated an explosion in the use of aluminium in glasshouses, for example at Edinburgh Botanic Gardens in the 1960s, and in the more recent glasshouses at Kew. Little building work was undertaken at Kew during the 1950s, when maintenance of the building stock was limited to the restoration of the Palm House in 1957-8.