Julian Harrap Architects and Jamie Fobert Architects working in partnership have secured planning permission for the redevelopment of the barns at Charleston Farmhouse, the historic country retreat of the Bloomsbury Group in East Sussex.

Sited on the spring line of the South Downs, between Brighton and Eastbourne, the £5 million project will provide additional visitor facilities in the carefully restored barns, alongside a series of new buildings.

“The context has been brutalised by industrial agriculture,” said Julian Harrap. “The challenge is to reunite the buildings and stitch the landscape back together, with the minimum intervention possible.”

The project sees a new refectory housed in the former threshing barn, whose steel frame – erected after a fire in 1981 – will be masked by the insertion of a tent-like soffit. Joining the threshing barn to form an L-shape, the former hay barn contains a lecture theatre, meeting rooms and study facilities. Its oak frame will be faithfully restored, and an adjacent granary building will be reinstated.

“We are trying to de-suburbanise the buildings,” said Harrap, who is aiming to revive their original character – as thoroughly documented in the paintings of Duncan Grant.

A series of new buildings define a second and third courtyard to the west, housing a 6,000-piece archive and a top-lit gallery space with three divisible chambers, of a similar scale in plan to the rooms in the farmhouse. Overhanging eaves shelter a walkway around the courtyard, echoing an aisle form in the hay barn.

These new additions are designed to complement their context, as contemporary timber-framed buildings wrapped in corten.

“The patina was inspired by rusting agricultural machinery in the surrounding fields, and echoes the bright orange lichen on the existing peg-tile roofs,” said Jamie Fobert. “The irregular roofline is a distortion of traditional barn forms to suit the internal functions.”