Eric Parry Associates'renewal of the historic and iconic St Martin-in-theFields site in Trafalgar Square, central London is currently on site. We look at the different issues the practice has faced on this project.
St Martin-in-the-Fields means different things to different people: local parish, internationally renowned chamber music venue, community-outreach centre, historic landmark, or perhaps somewhere for a quick lunch in the crypt. More than 700,000 people visit St Martin annually. For two centuries, its activities have evolved within the constraints of its site. Changing needs were met incrementally by haphazard partitioning without a strategic overview. Eric Parry Architects is working to change all that and squeeze every square centimetre out of the deceptively extensive site - larger than Leicester Square - by increasing the oor area outside the sanctuary by almost 50 per cent - mostly underground.
With a new pavilion on Church Path opposite the National Portrait Gallery, St. Martin will also increase its public presence.
John Nash was the first to undertake a restructuring of the St Martin site in 1826, creating Trafalgar Square on the site of the former Royal Mews, clearing land and widening surrounding streets. He also added the North Range terrace along the northern perimeter of the site and expanded the church yard, which was built over burial vaults - a new concept at the time. Nash's interventions made the church a prominent London landmark.
The work at St Martin today is in fact three major projects rolled into one, with a £34 million price tag. Careful restoration of James Gibbs' 1724 Church, which will strip away various Victorian interventions, is only the tip of the iceberg. A new L-shaped crypt and basement level, being excavated just over the London Underground tunnels, will wrap around the church occupying the full extent of the available site - both horizontally and vertically - all below grade. This undercroft, which will be accessed through the new entrance pavilion, will house a new hall, rehearsal spaces for musicians, outreach space for the Chinese community centre, a new kitchen for the restaurant and more.
The third piece of the puzzle is the refurbishment of Nash's North Range terrace. This has always housed a mix of vicarage and community activities and will continue to do so. A 3m-wide passage which originally provided access to the school is being infilled for extra space and a mezzanine is being inserted into the top oor for more offices. In short, every bit of space on the site above and below grade will become usable.
Eric Parry Director Robert Kennett, who has been working on the project for five years, explains that innumerable technical aspects of the refurbishment have been challenging.
Excavating a basement close to St Martin's shallow foundations and the North Range buildings required temporary retaining across the entire site. Low head heights in Nash's burial vaults rendered them unusable and a decision to demolish was taken early on with full support of English Heritage and the Georgian Society, all intimately involved in this project from the outset, though not always in agreement. Because the church foundations extended only a few inches below the crypt, the deeper spaces of the new basement were located away from the church.
Standard sheet piles were used against the church, while secant piles were used along the North Range buildings. The secant piling rig had to be carefully located to clear Nash's cornices above. The water table, 3m below the basement, and the close proximity of the Tube tunnels meant vertical dimensions were critical - a 2.7m clear head height was achieved for the basement.
The community-outreach activities were rehoused in a temporary building erected on site for the duration of the project.
Services for the new underground spaces are routed through a 1m-deep plenum created between the structural slab and a concrete oor slab which enables all cooling to benefit from the stable underground temperature of 13ºC. Max Fordham Associates has estimated that this plenum will generate as much as 4ºC of natural heating in the winter. The project also includes bore-hole cooling, another passive system, which takes water from the ground and circulates it through coils to cool the crypt. The only supplementary cooling is some standard units in the upper oor offices of the North Range building. Because the extract for the crypt kitchen could not be discharged into the churchyard above, an 85m-long duct runs horizontally through the new underground building into the North Range building and out through the roof.
The church itself has remained open throughout and will close only from May to December of this year for its own refurbishment programme. The east end of the nave will be reinstated close to the original Gibbs design by stripping a Victorian podium and choir stalls to make it more exible for musical performances. Small changes, such as reopening the fullheight stair halls at the entrance and adding glazed panels at eye level to the central doors, will transform the entry to the sanctuary.
The linoleum oors will be replaced with Purbeck stone and the plasterwork ceiling will be redecorated in a single tone.
Perhaps most significant is the replacement of all the coloured glass which was installed after World War II with clear handmade glass windows, similar to the windows of Gibbs' day. A new east window by artist Shirazeh Houshiary will casually allude to Eric Parry's oculus-like pavilion and lightwell.
Eric Parry's part in the regeneration of the St Martin site has an appealing clarity: restore the church to its Georgian glory, maximise below-grade accommodation and widen the church path to accommodate a new entrance pavilion and lightwells.
The entrance pavilion, which is to be made of translucent cast glass, will occupy centre stage on Church Row between Gibbs and Nash. Its kiosk-like form runs the risk of being the awkward newcomer, more brash than Nash, and its success will depend entirely on its proportions and detail design.
The most significant transformation of St Martin may simply be the quality of light. Nick Cramp of Max Fordham Associates observes that new lighting in the sanctuary will make the church 'brighter and more sacred'. 'The key, ' says Cramp, 'is lightness of touch'. This could be said of the project as a whole.