Café pavilion makes the most of Duke of York's Square

The strapline on the website of Alan Dempsey’s design studio  Nex runs ‘Connecting People and Places’ – a bit like Nokia before they faded from prominence. You hope that in this case,  Nex’s approach will have a little more longevity. That sure seems to be the intention of the former AA unit tutor, as he explains over coffee in his just completed café pavilion at Duke of York’s Square, a stone’s throw from Sloane Square via the gestural flourish of Peter Jones. Our conversation has broadly been about the privatisation of public space – but Dempsey’s interpretation is more nuanced than mine. Public space bylaws abound, he says; for him the bigger question concerns the terms under which you can use it and how private space can embody a civic, public component. 

He answered the question at Royal Wharf Pier in London’s Docklands by creating a public river walk on the way to his riverboat pontoon for Ballymore – a jetty projecting 130m into the Thames with the surprise of a glazed balustrade around a triangular pier that allows the public to get up close and personal with the rise and fall of the river. In a different but no less surprising way, there’s a rise and fall at Duke of York Square; one that subtly blurs the usually rigidly applied boundary between public and private. 

Nex’s Duke of York Square restaurant pavilion sits in architect PDP’s 2005 Cadogan Estate development. It reconciles the problematic geometries exposed in plan when the formerly walled-off, grade I-listed, 18th century drill-hall for the children of army widows was opened out to the King’s Road – before being enlisted as the new Saatchi Gallery. Dempsey says its curiously capped-off gated curved wall, in the form of an opening paper clip, inspired  Nex’s circular intervention; a building with no front or back; a curved, arched, precast Dolomite quartz concrete form that picks up on the wall’s language and then decides to run counter to it.

Less obvious in the firm’s 2012 competition entry for the pavilion was its wrestling with the notion of public space and how to intervene in the private square without ­losing any more of it to a stipulated 40-cover restaurant. Solving that produced a trinity of responses; to sink service areas of kitchen, store and loos into the basement below the restaurant; to generate an externally accessed roof garden on top; and, most dramatically of all, to make most of the glazed circumference able to sink into the ground, removing the boundary between pavilion and square. All three have been consummately executed, pandering to the discretion of the client while suggesting the tantalising possibility, like Granary Square at King’s Cross, of private space that seems to have become public by default. 

A staircase of timber ash on the ‘rear’ of the pavilion is revealed as a hidden route to the roof garden, that, until its low stainless steel gate is closed, offers people use of a 4m high eyrie, letting them escape the unseemly King’s Road congestion and lose themselves in the green canopy of plane trees on the former parade ground to the south. Run through with herbs and perennials, the experience, designed by landscaper Bradley-Hole Schoenaich, is intended to be as pungently sensory as it is visual. 

Internally, despite the drum form and hard surfaces setting up the potential for a perfect storm of cacophony, sending the kitchen below stairs has in the main dispensed with fad for open plan and the clatter of pans, in favour of more dignified acoustics. The well-detailed and attenuated ash slat ceiling radiating from the restaurant’s sparkling quartz concrete core soaks up the chatter of the ‘Made in Chelsea’ set to create instead a soft but lively acoustic reminiscent of Vienna’s genteel cinnamon-scented cafés.

But, of course, the pièce de résistance is the three 10m curved, laminated, toughened glass walls that, on activating, sink silently into the ground to marry the interior’s zingy black terrazzo floors with the square’s staid yorkstone setts. Developed with Swiss firm HIRT, which had only ever done a straight configuration, they overcame the panels’ change in centre of gravity, glazing stresses and strains to produce sealed units whose performance helped the building achieve a BREEAM Excellent rating. Eschewing hydraulic and robotic solutions, Nex chose a low-tech motorised one, sitting panels on a curved frame, counterbalanced by a steel universal beam, all sunk into a concrete perimeter pit. It can even be raised and lowered by hand. 

More than just a gimmick, the huge dropped glass sash makes the 40 covers in the limited space a viable proposition. And, Dempsey thinks, it means the pavilion can interact with the seasons in our temporal clime; for most of the year it need be neither fully open nor fully closed, but any number of states in between. An analogue-kind-of-space in the digital age; one that’s ripe for stealth appropriation – hell, occupation – by the square’s four million annual visitors. And all on the King’s road too. How punk is that?