Mountbatten House (formerly Gateway House), Basing View

Former headquarters for the paper merchants Wiggins Teape built in 1974-76 to designs by Arup Associates’ Group 2, with associated landscaping by James Russell.

MATERIALS: a pre-cast reinforced concrete frame clad with bronze-anodised aluminium and bronze tinted glass set in steel box mullions, with two projecting stair towers in blue engineering brick. Concrete slabs to the flat roof gardens over the offices, which have a cellular glass waterproof membrane covered in three layers of mastic asphalt protected by a cement and sand screed, and topped with soil to a minimum depth of 225mm rising to 900mmm.

PLAN: an almost square plan oriented north-south, almost symmetrical about a north-west to south-east diagonal axis, which to the south steps down on the diagonal in a series of terraces (roof gardens) down to a courtyard. The stair towers at the south-west and south-east corners have a square plan with rounded corners. At basement level is a large car park. The lower-ground floor consisting of plant rooms and offices, which give access to a courtyard with pond and stepping stones. The entrance and reception at ground floor level are flanked by a double height staff restaurant and plant room, with offices behind, giving access to a large roof garden. The first, second, and third floors each have an open plan office (some now subdivided) opening onto roof gardens.

EXTERIOR: the slightly raised, formal entrance facing Basing View, accessed via broad steps, comprises of two high wings of four storeys plus basement. At the junction of the wings a double-height opening, four bays square, signals the main entrance. The elevations are composed of a repeated 7.5m bay module, with full-width glazing, subdivided into five lights on a planning module of 1.5m. The external cladding consists of deep bronzed-aluminium spandrel panels with mitred joints and a chamfered frame (manufactured by Josef Gartner of Munich). The full height brick stair towers have narrow slit glazing. The stepped elevation to the rear south-east side of the building, is characterised by a series of cascading roof gardens abundantly planted with trees, shrubs and climbers. The glazing to the front of the building is flush with its concrete frame, whilst that to the rear elevations is recessed to limit solar heat gain.

INTERIOR: internal lay-out and circulation survives largely intact, though parts of the open-plan offices to each floor have now been subdivided. Internal features, fixtures and fittings include cruciform-shaped concrete columns supporting pre-cast coffered ceilings forming distinct truncated pyramids with integrated light fittings; the lift lobbies and staircase walls have travertine marble panelling, while the two curved walls to the stair towers are in exposed brick. The plant room has ceramic tiled flooring and skirting. In the basement a large c144m3 galvanised steel tank held rainwater to irrigate the roof garden (out of use in 2014).