High Church

If the Surveyor of the Fabric of Westminster Abbey, Ptolemy Dean, is feeling the weight of history on his shoulders, he isn’t showing it. For his new Weston Tower, which opened in June, connecting the abbey’s Poet’s Corner Yard at ground to the new Queen’s Diamond Jubilee Galleries in its eastern triforium, is the first major intervention on the site since Nicholas Hawksmoor completed its Western Towers in the early 1700s. And, as with the design and fit-out of the exhibition by MUMA, it’s a curious but satisfying melange of old and new, carried out, both architects argue, with the same sense of continuity as practised by Dean’s predecessors – back to its first surveyor, Christopher Wren in 1698.

In fact, as Dean explains, the triforium only started to take on any semblance of its original intent when in 1699 Wren replaced the decaying high-pointed roof with a flat lead one and installed a floor above the ambulatory’s gothic vault. High level gallery chapels such as these, constructed in the 1250s, were common in Norman churches in the 13th century but soon fell out of fashion. Until Wren’s floor installation, despite two stone access stairs from the north and south transepts, it would have been impossible to walk up here without negotiating the deep interstices of the vaults. Used as a makeshift viewing gallery and latterly just for storage, it was only in 2006 when the current Dean of Westminster was talking to an archaeologist who felt that the space should be revealed, that the idea of converting the attic to some useful purpose came about. With its magnificent views back along the nave and over the roof of the Henry VII Chapel to the Houses of Parliament, the new £23 million Diamond Jubilee galleries, bringing together key curated historical pieces from the abbey’s collection, are the culmination of that thinking.

Better access

Making the triforium accessible to all resulted in the Weston Tower, named after its primary donor Garfield Weston Foundation, nestled in the tight site of a former small toilet block between the south transept, ambulatory and Chapter House. The new stone-clad lift shaft, timber stair and hung steel glazed envelope is, Dean explains, ‘contemporary gothic’ – a direct response to the highly charged context; referential, historicist but in an uncanny way, startlingly modern. 
Its look was a pragmatic response to the design brief. The shaft had to be concrete to rise seven storeys and big enough to accommodate wheelchairs and carers, the timber stairs wide and of minimum riser height to ease the ascent of the crowds expected to visit. Faced with the context and the brief, Dean says he let the building tell him what to do. ‘We looked at a Scarpa-esque approach, but it was too big for a modern, minimalist solution. Too big not to be something; it had to play by the abbey’s rules. With the lift shaft square, we settled on the octagon form – two squares rotated – which if you look around is very much a Westminster trope, present on the famous 13th century Retable as well as all over the Henry VII Chapel.’ The strong geometry also clearly identifies the form, jostling with the competing geometries of Chapter House and Chapel, tucked behind Gilbert Scott’s 19th century buttress. The tightness of the site also necessitated the construction of octagonal cantilevered raft foundations, the soil dug out and sampled until it reached the consolidated bed of Thorney Island gravel 2.7m down. The abbey’s medieval builders had done the same, by instinct rather than scientific analysis.

The most distinctive aspect of Weston tower is its delicate glazed screen of thousands of individual leaded lights, inspired by Wren’s plain, rectilinear Renaissance tracery; but their fineness required structural gymnastics to achieve it. Coupled with Dean’s demand that mullions and transoms be as slender as possible, engineer Price & Myers settled on a radiating ‘crown’ of 203mm steel beams above the lift shaft and perimeter beams, its loads transferring down via eight 152mm universal channels which also house the drainage pipes for the steeply pitched octagonal roof. The glass screen was then ‘hung’ from these perimeter beams. With steel working best in tension, it achieved Dean’s requisite delicacy, resting lightly on the dressed concrete upstand outside at ground, and on the timber roof of the new lobby accessing the south transept. The tracery even yielded security benefits. ‘We had a blast consultant test the facade and it performs fantastically well,’ Dean explains. ‘The lead absorbs the blast and warps with only a few corner panes breaking – it seems a traditional solution to modern-day terrorism.’ The sinuous metal tracery that winds its way up the facade counter-pointing the orthogonality is, Dean admits, a caprice in the way Digby Wyatt’s intervention on the end structure at Brunel’s Paddington train shed was. He justifies this whimsy as a ‘functionality of the soul’.

The roof crenellations and steel columns are clad in lead, detailed all the way up with protruding chevrons that permit ventilation in the void between steel and lead work and loosely referencing, says Dean, the lead-clad Octagon of Ely Cathedral. At half landing levels, 135mm deep, 100mm wide secondary steel tee-beams run from the columns back to the concrete lift shaft and perform the dual function of stiffening the columns along their length, allowing them to be more slender but also to support the air-dried English oak staircase at half-landings as it runs up the lift shaft. Even the facing to this tells a story, with Dean cladding it in the 18 different types of stone used to build the abbey. It’s original chalky Reigate, the Burford that Wren re-clad it in and the Chilmark that Scott used, Caen, Clunch, Purbeck grub, Kentish Ragstone, the Portland of Hawksmoor’s West Towers. John Loughborough Pearson, 19th century architect of Truro Cathedral, even introduced Cornish granite to the mix. It seems the history of the Abbey is nothing if not a catalogue of the stones from which it is made, set in a capital that only offered London clay. ‘The Reigate’s so rare we had to dig it out of hole somewhere near the M23,’ Dean quips, ‘but the wall here expresses more about the provenance of the abbey itself and no slavish traditionalist would do that.’

What’s inside

There’s similar attention to detail evident in MUMA’s 900m² triforium galleries, though perhaps in a more intangible way – skills perhaps honed in its design of the V&A’s Medieval and Renaissance Galleries; there’s certainly a similar level of deference to the existing building. ‘When we first came up here with specks of dust floating around the space in the sunlight we realised that the most important exhibit was the abbey itself,’ recalls MUMA’s Stuart McKnight. ‘We had to ask ourselves how do we arrange 300 objects in this space without undermining its otherworldliness?’ The answer was to do the minimum necessary to make it suitable for the artefacts. And with many of them hundreds of years old it meant tailoring thematic curatorial demands with thorough investigations into the specific climatic nature of the triforium’s spaces; a laboured process carried out with environmental engineer Max Fordham. The bottom line was to avoid mechanical conditioning of the space by encasing artefacts fully and then positioning them to avoid all exposure to sunlight; no mean feat in a space shot through with gothic windows.

MUMA’s first move was to know what it was dealing with as regards the ambient temperature of the space, cognisant that it is okay for temperature to fluctuate as long as it doesn’t do so rapidly. ‘The walls are about five feet thick and when we monitored the diurnal internal temperatures we realised that the fabric performs well even at extremes, with a 10ºC differential between internal and external temperatures,’ says Max Fordham partner Laurence Owen. Clearly, the thermal performance of the glass was bad. Rather than adopting secondary glazing, which would have severely affected the look of the space, the team chose an in situ hand-applied solar control layer on the glass.

Also, since it’s an open space and part of the abbey, it was important to ensure that relative humidity remained within acceptable parameters. Two heating and conditioning units have been placed within the triforium to do this, fed off the abbey’s central heating system. These respond to a bespoke ‘aspirating’ sensor that Fordhams developed, connected to the fire alarm circuitry. ‘It sucks a little of the air out of the gallery and passes it over a heat and relative humidity sensor, which then activates the perimeter trench heating if necessary. The aim is to keep the RH in the 40%-60% range,’ says Owen.

But the real work for MUMA and Fordham was creating the complex virtual model of sun penetration of the space over a whole year to guide the positioning of objects. The galleries are arranged according to theme, but despite the apparent ‘ease’ of the space, each artefact’s positioning is in fact the result of a complex Venn diagram of curatorial intent, sunlight study and the architect’s aesthetic instinct. ‘It was a matter of ascertaining where sunlight enters and where we had deep shadow and configuring exhibits to avoid one and take advantage of the other,’ says McKnight. 

So as you walk around, Hawksmoor’s delicate line drawings enjoy the cooler shade of the nave and the supine funeral effigy of Catherine de Valois, wife of Henry V, will never suffer direct sunlight even though it stands at the centre of the space. Extreme situations such as early morning and late afternoon light are dealt with by BMS blackout blinds that actuate when necessary, but this will be outside gallery hours. The only thing visitors may register is the silent swish of MUMA’s sexy pale leather curtains occasionally being drawn. ‘We didn’t really get involved in the tech and interpretation of the artefacts, but as architects, more with their shapes and forms, we had a strong visual response to the exhibits,’ says McKnight.

Case design was by MUMA working with engineer Michael Hadi, fabricator Glasbau Hahn and metalworker TP Aspinall. MUMA decided on Purbeck stone to ally with that of the abbey, but McKnight says they were very conscious that it should not feel ‘grounded’ 16m above the nave. So the Purbeck stone exhibit cases are raised on chromed steel cruciforms, reflecting the oak floor and dematerialising themselves in the process. Dark patinated mild steel cruciform sections support items such as stone capitals – the adoption of a Miesian form that’s given added resonance by its setting. McKnight lauds the efforts of both engineer and fabricator – best evidenced in the sliding ‘morgue drawers’ that allow effigy and armour to be accessed out of the glass cases, imposing huge cantilever loads in the process; they glide in and out effortlessly

Taken together, both stair tower and exhibition space have a pleasing naturalness and repose; it seems clear that Dean and MUMA worked together on the galleries in an iterative design process. Careful curation has created a space that, while full of exhibits, remains spacious and deferential to the ancient space it occupies. And as for Dean’s new tower, he feels its ‘busyness’ is a suitable response to the complexity of its context. ‘By being full of its stuff, as everything around it is full of stuff, I think it simply goes away and disappears,’ he concludes. ‘Sometimes more really is less.’