Finely crafted stone lends style and substance to Squire & Partners’ first buildings at Chelsea Barracks

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Jack Hobhouse

Ten years after the first scheme for the residential development of Chelsea Barracks was derailed by Prince Charles’ intercession with developer Qatari Diar, the first completed buildings now stand on the 12.8-acre site. Permeability was a guiding concern of both the thwarted scheme by Rogers Stirk Harbour & Partners and the subsequent masterplan by Squire & Partners, Dixon Jones and landscape architect Kim Wilkie, but the two projects adopt quite different approaches to urban form and the use of materials.

Where the RSHP masterplan proposed an ‘urban campus’ of buildings in parkland, with an array of glass and steel blocks arranged end-on to Chelsea Bridge Road, the later scheme sought to establish a set of archetypal urban spaces, continuous with the existing grain, around which buildings are configured. These are principally streets and garden squares – a possibility afforded by a scale of development on a par with the historic Great Estates. As in the Georgian squares of Belgravia, the ‘squares’ are elongated, allowing efficient use of land with the greatest number of homes enjoying an outlook onto open space. Eight-storey buildings that line Chelsea Bridge Road are only marginally lower than RSHP’s nine-storey proposal, but heights drop away across the site to match existing houses to the east.

Having opted for a plan that is “of London”, the architects were equally concerned that the material character of the buildings should reflect their location, says Squire & Partners’ Henry Squire. The immediate context offers a variety of precedents, from the rusty red brick and pink terracotta of Lower Sloane Street to the cream stucco of Chester Square, but stone was selected for its durability, ability to suggest longevity, and its connotation with high value. Portland stone was specified because “if you use anything else, it isn’t really a London building”, says Squire.

The pale limestone is used across most of the buildings completed to date: three apartment buildings facing Chelsea Bridge Road have been designed by Squire & Partners, while 13 large townhouses to the rear are by PDP London, which also delivered a single-storey brick restaurant designed by Ben Pentreath, and the restoration of the listed Garrison Chapel. (Eric Parry Architects has designed more apartments on Chelsea Bridge Road, currently under construction, while Squire & Partners, EPA and Piercy & Company are lined up to deliver the final phases).

The scheme places an emphasis on “craft and integrity of materials”, says Henry Squire, and there was a concern to use stone in a way that recalled “the way it was historically used – not just as a veneer”. The apartment buildings’ self-supporting cladding is composed of 75mm-thick hand-set blocks with tight joints of less than 4mm. The architects’ initial intention was that the stone should be set in lime putty, removing the need for movement joints. In the event, cement mortar was used, but joints have been successfully disguised by blowing stone dust onto the wet silicone.

Facades are notably deep – almost a metre where the apartment buildings’ windows and balconies are flanked by fluted pilasters. “We were insistent with both the client and planners that successful stone architecture must have a depth of reveal”, says Squire. Thus, both the masterplan and outline planning application incorporated a design code stipulating two distinct parameters for each plot – net internal area and an external ‘building modulation’ line.

Stone is mainly taken from three Portland beds: roach (the youngest stone, heavily cratered by the remnants of shells), whitbed (lightly pockmarked by fossils) and basebed (the oldest and smoothest). The townhouse facades use a mix of base bed and whitbed stone, while the apartment buildings make use of all three types. The deeply pitted honed roach stone is used at the base of the building, where it suggests a kind of rustication, and where its texture – instantly evoking “a million years of history”, observes Squire – can be best appreciated by passers-by. Courses are articulated by deep scalloped cuts, “almost as though a giant saw blade had lightly touched it and then come back out again”, says Squire. “We’re trying to show something of how you carve stone”.

Within the rusticated base, course heights are uniform to lend a sense of solidity and stability, but they vary within the whitbed stone piers rising above to lend animation and a more “natural” texture to the facade. Further embellishments include cabled fluting to the stone pilasters, and intricate fronts to the projecting balconies. Formed from waterjet-cut aluminium plate, these incorporate botanical motifs derived from illustrations found at the nearby Chelsea Physic Garden.

Portland stone is vulnerable to staining, and having learnt from experience on earlier buildings, “we have finally introduced cills with big falls”, says Squire. The careful crafting of stone is also evident inside the building, where Squire & Partners was responsible for the delivery of schemes by other interior designers.

The walls and floors of the foyers are lined in Paloma limestone, and the extensive underground spa complex is bedecked with a huge range of exoctic marbles and onyx sourced from around the world. S&P associate director Steven Hill made over 20 trips to Italy, where stone was machined in a variety of workshops – including one that had supplied material to Michaelangelo – to inspect all cut stone prior to transportation and installation. Stone is a natural response to the client’s brief for ‘luxury’, says Qatari Diar’s head of design, Lee Hallman, “but there’s still a lot of design work and care involved in making it feel truly special”.

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