The Spectrum Building (formerly the Renault Distribution Centre)

The Spectrum Building, formerly the Renault Distribution Centre, is a warehouse built in 1981-2 to store vehicle components, with integrated showroom, offices and training facilities. It was designed by Foster Associates (design work initiated in 1979) and engineered by Ove Arup and Partners. The main contractors were Bovis, with Tubeworkers as steel contractor.

The building comprises 24,000 square metres in total: 20,000 square metres of warehouse space and the remainder divided between administrative offices, canteen, training facilities and showroom. It is predominantly single storey, with a two-storey block of offices and training centre positioned between the top-lit warehouse and the highly glazed canteen and showroom.

The plan is articulated by 42 modular units, each 24 metres square, arranged around a central column or "umbrella mast". Of these, 36 modules enclose the warehouse, which has sixteen loading bays at its north end. The building tapers towards its more open southern end where the showroom is located, terminating in an open single-module canopy that functions as a modern porte-cochère.

The structure is steel-framed on concrete foundations with a concrete four-hour fire wall and moveable internal partitions. The roof is a PVC membrane. The walls are set back 2 metres behind the first row of umbrella masts. The defining structural system employs tubular steel columns or masts, each with radiating spars supported by ties fanning out at 45 degrees from the top of each mast. Where a tie reaches a beam at an intermediate point, it is threaded through the beam and supports the joint with the next beam from below. Holes in the steel beams facilitate this threading and contribute visual character. The Renault Centre is an un-braced structure; the rows of tautly stretched "umbrellas" work together dynamically to create a single integrated structure functioning like a series of portal frames. The masts are stiffened by pre-stressed ties positioned one metre from each major mast. Specially designed castings of spheroidal graphite cast iron connect the ties to the masts, emphasising the perpendicularity of the masts themselves. The masts are post-tensioned using the Pilgrim Nut jacking system employed for ships' boilers. Beams at the edge of each roof section are tightly sealed with neoprene. The building is drained through plastic pipes within each column. The roof ceiling comprises profiled metal decking, insulation and PVC covering. The exterior features slightly ribbed steel cladding and trapezoidal roof lights on the north side of each roof panel section.

The glass walls of the showroom and former cafeteria are of armour plate bolted directly to steel frames using four bolts at top and bottom, countersunk to the outside with only silicon mastic between the 10 millimetre thick panes. This fixing system, developed with Pilkingtons Ltd., allows for flexibility. Specially formed sun screens, which double as catwalks, are angled at 15.5 degrees elevation.

All construction elements were manufactured off-site by Tubeworkers at their Warwick factory to ensure maximum quality, and the building was assembled on site in sixteen weeks.

The interior retains considerable evidence of its original design and use. Flexible partitioning divides the offices at mezzanine level above the former showroom. A steel left-hand stair to the mezzanine, projecting into the former showroom, survives alongside a more recent right-hand stair. The yellow steel umbrella posts and profiled metal deck ceiling of the former showroom remain fully visible from below. Windows throughout have opal-coloured perforated blinds and semi-cylindrical convector heaters. Former ground-floor office areas, now converted into dance studios, retain polished concrete coffered ceilings resting on polished concrete columns.

Internal walls, including those to the corridor separating the former showroom and warehouse, are built in concrete blocks in stack bond. The corridor features a perforated metal ceiling with built-in lights. Black painted doors with circular lights and tubular handles are present. A steel and aluminium stair at the east end of the corridor leads to the mezzanine above.

Within the warehouse, the structure and ceiling remain fully exposed. The reinforced concrete floor slab with mongrano topping is left unfinished, as in the training area where some top-hung car manufacturing machinery survives. The glazed staff canteen in the far north-east corner of the warehouse is intact, with toilets featuring tall pivoting doors. Kitchen, toilet and reception areas are covered in rubber; other areas are painted.