Inside the new Sloane Building development: from one historic Edwardian school to 18 multi-million-pound apartments

In its original guise as a girls’ school – the first purpose-built secondary school in the country - Sloane Building in Chelsea must once have housed many a trophy for academic endeavour and athletic prowess.

Now, the imposing red-brick building just off the King’s Road, designed in 1908 by architect Thomas J Bailey, is a trophy cabinet in itself: a collection of 18 one-off, exceptional properties with the luxurious dimensions and quirky spaces that come with having started life as an Edwardian school.

Take one of the properties, dressed by interior designer Joanna Wood, where the listed glazed brick stairwell that girls once hurtled down on their way to the gym has been turned into a split-level bathroom with a copper bathtub at the bottom of a white marble staircase.

And then there’s the old assembly hall, revived as the vast living room of a 6,500 sq ft private apartment, with a ceiling height of nearly 25 ft (7.4m). Coming soon, too, in the detached converted 1840s chapel, are two large houses of 6,500 sq ft and 8,500 sq ft, to be dressed by Thorp Design.

Some of Sloane Building’s asking prices are as lofty as their dimensions. The apartments range from £3.25m to £18.5m, through Savills and Knight Frank, in a market where values have fallen by 15-20% since their 2015 peak. Savills’ director Brian d’Arcy Clark estimates the two chapel houses will fetch £2,500-£2,750 per sq ft, which places them at somewhere between £16.5m-£21m.

D’Arcy Clark, who has been selling prime London property for decades, says this "is the worst market I’ve ever known”. Yet six of the apartments sold off-plan to British, European and Middle Eastern buyers.

And now that prospective buyers can see the near-finished result, he is confident the rest will follow. “We’re keeping prices reasonable to get it sold. I think we’re going to win by doing that in this market,” he says.

“It’s quite an ego trip really,” says Clark, gazing across the expansive living area of the The King’s Hall – one of the two shiniest trophies in this cabinet.

Around three sides of the gargantuan main room, there is a mezzanine gallery with bedrooms and bathrooms where classrooms and science labs once stood. In the middle of the living area is a bespoke pod whose curving stairway leads to a floating living area. Below is a dining table that comfortably seats 20, according to Clark.

“This property is priced at £18.5m and I think we can get that every day of the week,” he comments. “You won’t find a flat of these dimensions anywhere else in London. We’ve kept it as a white canvas as the buyer will certainly have their own ideas about what they want to do with it and they will almost certainly have their own interior designer, too.”

They may also want to buy the two apartments priced at around £4m and £4.5m on either side of The King’s Hall. “I can see a very rich buyer wanting to put their staff or kids in them. Then you have a complete private floor,” he says.

It certainly is an extraordinary space - as are all the Sloane Building’s flats, each of which twists and turns and climbs up and down in unexpected ways, some with private gardens and inner courtyards. All were designed to fit around the Grade II listed features of this four-storey building, that was a school until 1970, then Britain’s first adult education college, and latterly the Kensington and Chelsea College – until it moved next door.

While Tenhurst were waiting for planning permission, the building was also used as a film location for The Theory of Everything, with Eddie Redmayne – in the role of Stephen Hawking – scrawling on blackboards in its recreated classrooms.

While The King’s Hall has been left as a blank canvas for its future buyer, the building’s other standout trophy, The King’s Penthouse, needed a helping hand, from designer Joanna Wood.

“We felt it would be a struggle to sell something of this size without the lifestyle to go with it,” she says, as we enter a voluminous double-height entrance hall that simply features a grand piano, a pod staircase, and Tracey Emin’s illuminated “If music be the food of love” installation on a vast gallery-like wall. “Anyone with an art collection should apply,” adds Wood.

At the top of the feature staircase, there’s a large, fluttering pendant, by Parisian artist Christel Sadde, that features what look like hundreds of gold bars. Fitting, perhaps, given the £18.5m you will need to buy this five-bedroom, 6,150 sq ft penthouse (the contents can be negotiated separately).

With its mix of high and low ceilings, columns that run down the middle of the main living space and lots of split levels, designing the penthouse was an exercise in very complex space planning, according to Wood. “You have all the constraints of the original building, but that makes it much more interesting. You need to give a raison d’être to all the spaces,” she says.

Her solutions here include turning awkward or darker spaces into family snugs, a cinema room and a study – plus that most Instagrammable of split-level bathrooms.

Two lifts lead directly into the penthouse – one into the entertainment area, the other into the bedroom wing. Press a button in the living room and a glass roof opens, leading to five roof terraces totaling 1,500 sq ft, with London-wide views. Wood thinks the likely buyer will be under 40.

Unusually, for a super-prime development, there are no shared facilities to speak of, beyond a small gym in the basement. Buyers balk at high service charges, says d’Arcy Clark, so they have minimised the extras. “Residents can always opt to build them in the basement if they want,” he says.

There is one extra they might like to splash out on, however – one of the 50-or-so underground parking spaces that cost £100,000 each. “It’s hugely, hugely worth it,” says D’Arcy Clark. “You get a clean, tidy space with secure access to your flat. In this area, as London goes anti-car, it’s worth every penny.”

You can only imagine what those Edwardian pupils would have made of their old storage space for school books and gym kits being sold as £100k-a-pop parking spaces in 2019. In the century or so since the Sloane School first opened, it has been a learning curve indeed.

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