Rolfe Kentish examines Rogers Stirk Harbour & Partners’ major development at the British Museum
The British Museum, founded in 1753, was the world’s first national public museum. It opened initially at Montagu House in 1759, then in the new Smirke ranges and the round Reading Room, completed by 1857. The British Museum Library, housed in the round Reading Room and surrounding courtyard infill, was incorporated into the British Library by act of parliament in 1973 and, for the most part, migrated to the new St Pancras building in 1998. In the space vacated, Foster & Partners’ Great Court project (2000) covered the courtyard, restored the round Reading Room and extended the museum. The King’s Library was restored in 2003 for use as an exhibition space. Some British Library functions, including the bookbinding workshop, remained at the British Museum until the British Library Centre for Conservation was completed in 2007.
The very compact and constrained site for the British Museum World Conservation & Exhibitions Centre (WCEC), designed by Rogers Stirk Harbour & Partners, was found in the north-west corner of the museum’s Bloomsbury estate: first, in the narrow courtyard – almost a light well – between Sir John Burnett’s 1914 King Edward VII Galleries and Smirke’s north-west range, previously occupied by the book bindery, and second, in the open area to the west of the King Edward VII Galleries facing Montague Place.
The provision of flexible, state-of-the-art, on-site facilities for the conservation of museum collections, the reception of acquisitions, the despatch and receipt of loans, sustainable storage, and display is now a fundamental goal of world-class museums, and the new WCEC will no doubt be the envy of many. Four key functions are accommodated: a large exhibition gallery, conservation studios and science laboratories, storage, and a collections hub. The new facilities will serve the museum’s own ‘internal archaeology’ – research and teaching about the items in its collections. The majority of the area requirement in the brief constituted essential ‘behind the scenes’ museum accommodation: the new public Sainsbury Exhibitions Gallery occupies just 1,100 square metres of the 18,000 square metre gross floor area. Other ‘back of house’ areas include 5,100 square metres of environmentally controlled storage and 3,000 square metres of conservation studios, laboratories and staff areas. The sheer amount of floor space combined with the available site area, taking account of neighbours, as well as keeping away from adjacent British Museum windows and access points, meant that a significant proportion of the accommodation would be underground.
The publicly visible part of the site is situated in the interstices between the Portland stone-faced classical King Edward VII Galleries, on Montague Place, the 1930s Portland stone buildings of the University of London on Malet Street, and the eighteenth-century London stock brick backs of Bedford Square terraces.
The building’s lucid and flexible organisation is apparent in the clear demarcation of service and served spaces – as in Louis Kahn’s Richards Medical Laboratories. There are four main superstructure ‘pavilions’, with four stair, lift and service cores. The disengaged pavilions are connected to the rest of the museum by separate bridge links. Extensive basements are used for close-controlled storage and vibration-free specialist laboratories. At lower-ground level there is a main horizontal logistic floor which connects into the museum’s back-of-house horizontal goods circulation. On the principal floor level of the museum is the large new Sainsbury Exhibitions Gallery. This ‘blockbuster’ gallery, running east-west, occupies the full extent of three of the four pavilions: at 16 metres wide, 70 metres long (four structural bays wide by 14 long) and six metres high, the 1,100 square metre ‘white box’ is conveniently and directly connected to the Great Court via newly refurbished rooms – ticket hall and shop – in the north-west Smirke range.
The four-storey steel superstructure sits on the in-situ concrete substructure. The superstructure is an orderly, prefabricated steel frame of RHS columns and two-way spanning vierendeel trusses, arranged on a four by five metre grid. Columns are omitted mid-span on the east-west central axis, making the central bay eight metres wide. Post and beam connections are made with straightforward spigots and bolts; visible diagonal bracing is used at the ends of each pavilion – appropriate for a studio workshop space – while vertical stability frames are located in the cores. The stair and lift cores are free-standing with links to the pavilions. At the principal level of the main galleries, the 16-metre full-width clear span of the new Sainsbury Exhibitions Gallery is achieved by storey-height vierendeel trusses in the floor above. Plant is located in this floor above the gallery, rather than on the roof or in the basement. There is an eight by 20-metre, six-metre-high studio at the principal floor level for conservation work to large objects, as well as a mock-up studio for testing installations in the Sainsbury Exhibitions Gallery. Two floors of daylit conservation studios and staff facilities sit above the plant. The top floor has the benefit of controlled natural top light.
Screed-topped precast hollow concrete floor slabs span between the top chords of the Vierendeel trusses. The openings in the trusses are used for the distribution of mechanical and electrical services – as in Kahn’s laboratories – cable trays and sprinklers, thereby obviating the need for raised access floors. The lower chords of the trusses set the level for the lighting and acoustic panels; they are also used for attaching items of equipment. The top floor has extensive externally shielded roof lighting, daylight from which is further filtered through the trusses and M&E services. The absence of suspended ceilings allows for easy detection and removal of possible infestation and contributes to the feeling of spaciousness in the studios. Decontamination, acclimatisation, wet and dirty rooms and chemical laboratories with fume cupboards are partitioned off and separately serviced.
Three levels of basement – the lowest at 19 metres below ground level – were heroically excavated using a palisade of secant piles and ‘top-down’ construction following the excavation of 37,000 cubic metres of soil. It is remarkable that 68 per cent of the floor area of the WCEC building is underground – comparable with the British Library at St Pancras, where the lowest level is 24.5 metres below grade. Extensive vibration monitoring took place during construction to prevent damage to collections in adjacent stores and galleries. Heavy concrete construction provides thermal mass for the steady environmental conditions required for conservation storage, as well as good bearing for the loads imposed by compact mobile storage racking. Vibration-sensitive equipment, such as electron microscopes, is also located in the basements. Secondary drainage is provided for the secant pile walls and for removal of sprinkler discharge. Perhaps uniquely in London, there is an enclosed, five-storey, 42-tonne truck lift – a collection handler’s dream – providing access for 15.5-metre-long articulated lorries to internal loading bays and docks, with links to other goods lifts, for the secure and environmentally controlled delivery and despatch of loans and acquisitions.
The ‘pavilion’ design of the superstructure and the basements allowed construction works to proceed with minimal disruption to the museum, its staff and the public.
The interiors are characterised by the aedicular steel structure, concrete floors and layered diaphanous external walls. White-faced, black-edged high-pressure laminate is used to make the furniture and partitions. Not a single piece of wood – or any other natural material – is to be seen. The steelwork is painted with anthracite-coloured paint. Only the wall panels in the stair and lift cores are coloured orange or green.
Externally, the building presents a neutral, almost reticent, face to Montague Place and the return facing the back of Bedford Square. A single free-standing stair tower is placed in front of the cast glass facade of the northern pavilion of the WCEC on the notional building line set by the King Edward VII Galleries, its height reaching the latter’s cornice. The tower serves the top two conservation studio floors and the lower-ground logistics floor – a fire escape and accommodation stair sheathed in crisply detailed Portland stone and aluminium rainscreen cladding, with vertical glazing on the lines of disengagement. The same treatment is applied where the other stair and lift cores manifest themselves. The elevations between the cores have ground-to-roof cast glass rainscreen cladding suspended from solar shading maintenance walkways mounted in front of aluminium curtain walling, with the addition of adjustable louvres to prevent direct sunlight entering the conservation studios from the west. The structure and occupants of the building are therefore best seen at dusk when the internal light radiates through. The architect describes the approach succinctly as one of harmonious ‘contextual modernism’.
Rogers Stirk Harbour & Partners