This is Sky Pool
by Claire Dalton
If you looked upward from the COVID-empty streets of Central London in late September 2020, you'd have seen something incredible happening. An acrylic box, the sides 20cm thick, weighing 50 tons, was being hoisted skyward to become a gossamer bridge between two buildings…
The majesty of Sky Pool; photo courtesy of EcoWorld Ballymore
This is Sky Pool and by early summer 2021, it will be filled with 148,000 gallons of water, allowing swimmers an uninterrupted view downwards as they cross the 14-metre gap from building to building, 10 storeys from the ground. A substantial feat of engineering and architecture, the project has resulted in a transparent basin suspended 115ft above ground. Its home is Nine Elms, a residential and commercial development that overlooks the new US Embassy in London, and one which dwarfs any development of its kind in Europe at the moment, in both scale and ambition.
Phase two of Nine Elms saw developers EcoWorld Ballymore challenged to create a rooftop pool in the only available space — the tenth level roofs of the two westernmost buildings. It was proving impossible to find a design solution for a single 25m pool on one side or the other. This is where a game-changing idea by Sean Mulryan, Chairman and CEO of Ballymore, of not only a swimmable ‘bridge’ between buildings but also a transparent structure, came into play.
Once the idea was in place, the concept was developed and realised by some of the best minds in the industry. Designed by HAL Architects, structurally engineered by Eckersley O’Callaghan and created with world-leading acrylic fabricators Reynolds Polymer Technology, the pool draws on expertise from some of the world’s major aquariums.
Photos courtesy of EcoWorld Ballymore
Video footage from the off-site construction base located in Colorado — 4,720 miles away from its eventual home — shows strings of acrylic take flight as the material is sanded, the sides of the pool are shaved, shaped and finally glossed until fully transparent. Lengths of welders’ light flash outwards from machines as immense steel beams are finished, treated and tested. A bearded USA-capped crane driver — in what must have been one of his most stress-inducing workdays — shifts the controls of a beige Giraldi’s machine to move giant see-through parts. The structure — made up of two 5.5m stainless steel ends on either side of a 14m acrylic belly, measuring 5m wide and 3m deep — spins slowly, restrained by thick fabric straps. When filled, roughly a third of its 90m3 of water will be visible inside the translucent structure, with the remaining liquid extending into the buildings on either side.
Chairman and Ballymore Group Chief Executive Sean Mulryan said the project represented an incredible milestone that so many great minds worked together to achieve. "When I challenged the team to find a way to build a wholly transparent pool suspended between two buildings, they didn’t think it was possible. Ecoworld was a brave partner to back this crazy vision of ours. Now here we are, having challenged the boundaries of design, construction and engineering. The Sky Pool is a fantastic new architectural landmark for London, a stunning amenity for our residents, and a legacy project for our team.”
The live streamed launch on May 19 2021 will be suitably unconventional, with a synchronised swimming performance planned by world-leading water performers, Aquabatix — never before have they performed in a transparent pool floating in the air. But then, conventional is not EcoWorld Ballymore’s USP and there is arguably nothing about the Sky Pool that could be described as necessary or sensible. No one needs it. But they want it. Or at least, they do now.