The client couple - a geology lecturer and consultant, and his wife, an architectural librarian - needed space for high-tech geology communications systems, with which he communicates worldwide with other geologists in his field, and filing and storage space for his librarian wife. The extension also divides the garden into usable landscaped spaces.
The detached house stands in the centre of a large plot on a minor road in the village of Chalfont St Giles. A private drive runs south from the road along the west boundary of the garden. The back of the house is south facing. Robert Evans worked closely with Jenny Coe, a landscape architect, to create an environment which integrates the outdoors and indoors. The new extension, at the back of the house, is composed of a wing which extends from the living room, dividing the back garden into, on the west side, a quiet court with a large willow tree at its centre, and, on the east side, a pergola-bordered completely private lawn, separated from the main garage and entrance area by the extension itself.
The extension is constructed of conventional domestic materials: local Buckinghamshire brick for the outer leaf of a cavity wall and an inner leaf of blockwork, covered with a pitched roof of Redland Rosemary clay tiles. Set at an angle of 20degrees to the main house it is parallel to the garden boundaries. It is divided into a 'solid' part, the office, enclosed by brick walls on all four sides, and a 'light' part, a conservatory with a glazed wall and glazed roof, which connects with the house. Access to the extension is from the original living room via a pair of sliding doors. Above these, a new bedroom window fits snugly into the pitch of the roof and looks down into the new conservatory space.
To cope with the large amounts of storage required by the client, the office has a suspended storage gallery, accessible by a steel ladder, in the space formed by the pitch of the roof. It consists of two sets of shelves enclosed in a ply skin with a light floor of welded steel grating set between them. The edges of the ply skin curve round to form a soffit, reducing the apparent bulk of the gallery. Robert Evans used this idea in a previous project, a Cornish chapel with a steeply vaulted roofspace in which a three-bedroom gallery was inserted with curved edges to the soffit. He explains: 'The gallery is designed to give the impression of an object floating in space; this idea is reinforced by the curved edges which make the gallery appear less bulky, and by the almost transparent floor which lets light through. The curved edges of the soffit also create a much easier transition between gallery and sloping roof - one is visually aware that the roof is flowing past it.'