On a hot summer's day in 2013, the team at Ballymore gathered to discuss where to locate Embassy Gardens’ outdoor swimming pool. When they decided the space on top of the new Legacy Buildings wouldn’t be sufficient, they had an idea – one that would lead to a world first in engineering.
‘We decided the only space large enough was between the buildings,’ says Tristan Stout, Senior Development Manager at Ballymore. ‘So we started to research images of aqueducts. If those structures could span valleys, we believed we could build a structure to span two buildings.’
Originally, the idea was to bridge the gap with steels and install glass discs to allow sunlight through. But as thinking developed, the gauntlet was thrown down: the pool should be a sky pool, something transparent so that swimmers could see the ground and people below could see the sky.
With the idea catching the imagination of Ballymore’s CEO Sean Mulryan, the team brought in Arup Associates, the architect practice bringing Sir Terry Farrell’s master plan for the area and development to life.
‘The challenge from Ballymore was if we do this, we need to do it transparent,’ says Hal Currey, then architect at Arup Associates. ‘We needed to come up with something dynamic enough to engage interest and start us on the journey.’
Hal and Arup went away and developed detailed drawings, showing how the 14-metre distance could be spanned by, what they imagined at the time, a glass structure. However, a conversation with Brian Eckersley, structural engineer at Eckersley O’Callaghan, introduced a new material to the mix.
If you’ve been to an Apple retail outlet anywhere in the world, you’ll probably have seen Eckersley O’Callaghan’s work. The firm specialises in structural glass, which made them the obvious partner to bring into the Sky Pool project. But the engineering firm suggested a better solution.
‘We looked at structures with enormous hydrostatic pressures, like aquaria,’ says Brian Eckersley. ‘In all of these, it was acrylic not glass that had the potential to deal with big loads in critical situations.’
After a series of technical drawings and behavioural analyses, the dimensions of the pool were decided. With sides 200mm thick and 3.2 metres deep, and with a bottom 300mm thick, the acrylic pool will span the 14-metre gap between the buildings, with steps and filtrations systems sitting either end, and five modes of lighting to add to the feeling of magic.
‘There are other examples swimming pools like aqueducts connecting two buildings, like Marina Bay Sands in Singapore,’ says Eckersley. ‘But there’s never been something transparent spanning two buildings like this. Once you swim off, you can look right down. It will be like flying.’
This year, the Sky Pool will be manufactured ready for transportation to Embassy Gardens, either across land or along the River Thames. If it comes by road, traffic lights and bollards will need to be taken down. If it arrives by river, Nine Elms Lane closed for the day to lift it from the Thames.
‘You have to have an open mind on a project like this,’ says Ben Blackwood, Senior Design Manager at Ballymore. ‘From logistics to lighting to landscaping, there’s a lot to think about. But somebody has to push the boundaries. If you worry about things, you’d never get out of bed in the morning.’
In 2018, when residents get out of bed at Embassy Gardens, they will be able to float through the air in the world’s one and only Sky Pool.