Foster and Partners'£43.3 million National Botanic Garden of Wales at Llanarthne in Carmarthenshire is set to open to the public next Wednesday (May 24). The centrepiece Great Glass House, sitting within the 227ha Middelton Hall estate, is dedicated to horticulture, conservation, science, education, leisure and the arts and has been half-funded by Lottery money from the Millennium Commission. The elliptical domed biosphere is the largest single-span glass house in the world and has the geometry of a torus, tilted towards the south. In plan it is 55m by 95m with a roof height of 14m at its apex. Its tubular steel arches are laid out on a regular grid from the centre, providing structural support for the extensive glazing. Inside will be plant specimens from Mediterranean climates around the world.
Air through put - crucial for the plants - is controlled by means of an exterior sensor and automatically pivoting glass panels.