Hidden depths

From London town houses to Swiss chalets, swimming pools are now performing the ultimate disappearing act – and transforming into cinemas and ballrooms at the push of a button. Katrina Burroughs dives in

The Lewisohns’ pool, built by London Swimming Pool Company
The Lewisohns’ pool, built by London Swimming Pool Company | Image: Christian Stacey

International party people with a flair for the theatrical, health-conscious folk after a versatile spa-cum-gym, and parents who want a flexible family room that switches from swimming bath to cinema at the press of a button are now fitting their homes with a nifty new feature: a disappearing pool.

A rehearsal taking place above the Lewisohns’ pool
A rehearsal taking place above the Lewisohns’ pool | Image: Tony Line

“We have always had an indoor pool with this house,” says Charlotte Frost of the home she shares with her husband, Robert, a commodity trader, “but we often thought how wonderful it would be to have all that extra space when the pool was not in use, particularly with four spirited young children to entertain. Inspired by a favourite old Hollywood movie, where the floor retracted to reveal a pool underneath, we consulted with our architect about the chances of us doing this ourselves.” The film that fired Frost’s imagination is It’s a Wonderful Life, which features a scene in which James Stewart and Donna Reed dance the Charleston, unaware that the parquet beneath their feet is slowly splitting in half and water is rushing in to fill the gap. The two fall into the pool and other guests follow, until the party is taking a black-tie-clad dip.


Taking their lead from Stewart and Reed, the Frosts commissioned a garden extension to their south-west London home with a 9m by 4m put-away pool. The project was completed in 2011 by Guncast Swimming Pools (similar schemes from £200,000), working with Alan Higgs Architects. However, instead of parting in the middle, the floor of the Frosts’ pool sinks to reveal the water. “The reason why the room is so fantastic for us is that it is a space we can turn to any use,” says Charlotte Frost. “One day it can be a badminton court and the next a Pilates studio; at night it transforms into a cinema or a party room for 100 people. And, of course, some days it’s just a pool.”

The disappearing pool at Les Trois Couronnes, Verbier
The disappearing pool at Les Trois Couronnes, Verbier | Image: Savills Alpine Homes

Since the It’s a Wonderful Life scene was filmed over half a century ago in the Swim Gym at Beverley Hills High School, technology has moved on significantly. The now-you-see-it-now-you-don’t trick is no longer restricted to public baths. The leading manufacturer of domestic disappearing pools is a Belgian firm called Hydrofloors, which constructs its floors from stainless-steel beams underpinned with buoyancy packs. When the floor is at its highest point, it sits above the water, and the pool is invisible. As the floor is noiselessly lowered via cables and pulleys, taking an average of seven minutes to reach the bed of the pool, water rushes out around the 8mm gap between floor and pool wall. Thanks to locking pins that slide into the pool-shell walls, the floor, at its highest point, can routinely take a load capacity of 350kg/m2. And, according to the makers, the design has been adjusted (on request) to support a Bentley Mulsanne with a kerbside weight of 2,685kg.

The Frosts’ pool, created by Guncast Swimming Pools and Alan Higgs Architects 
The Frosts’ pool, created by Guncast Swimming Pools and Alan Higgs Architects  | Image: Peter Cook/View

Such apparently niche requirements are not uncommon among Hydrofloors’ clientele of sheikhs and senators, captains of industry and finance, says sales and marketing director Ron Plompen. Although its pools cost £200,000 to £500,000 to supply and install, orders are escalating. “At the moment we are quoting on 10 to 15 projects a week. Last year it was more like two to five. Our customer base is relatively small, but we often do several houses at once for the same person; for instance, a client might be building houses in London and Dubai. At the last meeting we had in the US, the customer was building three houses in three states and needed four pools.”

The Frosts’ pool with its floor raised
The Frosts’ pool with its floor raised

In major cities, where square footage is scarce, basement installations are proving the most popular option. Tony Line, MD of London Swimming Pool Company, specialises in such projects. He has recently completed one of his most challenging constructions, a 12m by 4m pool at South End, an award-winning development on a quiet Kensington street by Arek Palka of AP Arcon Construction. “South End is the most unusual job we have carried out, due to the very deep excavation required – 13m – to accommodate the 2.2m-deep pool on the third level below ground,” says Line. “It’s probably the most deeply located pool in the capital. Access was the biggest challenge. The 4m lengths of stainless steel that make up the moving floor had to be transferred down through a narrow opening, then joined in situ.” The pool room-cum-ballroom cost £350,000 to create, and the house is on the market for £16.5m with Knight Frank.

The pool created by London Swimming Pool Company at South End, Kensington
The pool created by London Swimming Pool Company at South End, Kensington

In these dual-purpose basement rooms, it’s crucial to have a flexible lighting plan that can be altered to match the two very different uses of the interior. The scheme at South End was created by Lucy Martin, design director at John Cullen Lighting, by illuminating the area with a mixture of tungsten halogen and both white and coloured LED lights. “The lighting was used to soften out the space, give it warmth and atmosphere,” she says. “We built in slate feature walls with downlighters skimming them to add texture, and created a coffered ceiling, lit with concealed LEDs, to give a sense of height. The lights are controlled on dimmable circuits, and you can knit the circuits together to create different scenes. It’s a bit like mixing on a record deck; you have swimming and dancing, afternoon and party modes.”

The pool area at South End, Kensington, transformed into a dance hall for a visiting television crew
The pool area at South End, Kensington, transformed into a dance hall for a visiting television crew | Image: Peter Northall

The ultimate party room, featuring a super-cool put‑away pool, has recently been completed in a luxury chalet in Verbier. Although many disappearing pools are confined to subterranean spaces, this one has striking views across the mountains. The chalet, Les Trois Couronnes – on the market for SFr40m (about £28.1m) with Savills Alpine Homes, or to rent from about £60,000 per week – is the pet project of perfectionist local developer Caspar Schübbe. Set inside a Bond-villain-style reception room, with a timber-clad bar and an upholstered day bed suspended over the water, the 10m by 4m Hydrofloors pool has walls and floor decorated with 65,000 mosaic tiles, and an online music-streaming database linked to lighting and jets in the water. At one end of the pool, a glass wall allows swimmers to gaze out at Le Grand Combin mountain range; opposite, a glazed partition showcases a second hybrid room, a banqueting hall/art gallery.


It certainly all sounds picture perfect, but experts agree that there are hidden challenges to installing a disappearing pool. “It’s not something that can be retrofitted easily,” says Christopher Gaylord, head of architecture at Janine Stone Interior and Architectural Design. “Ideally, you need to be building a new home or an extension.” Simon Williams, MD of Olive automation specialists, says owners don’t always realise that, while the “reveal” can be swift and theatrical, putting the pool away takes time and requires more complex changes to the air. “When the pool is exposed, the temperature of the air needs to be higher than that of the water, or the water will condense on the walls. This means that when you want to convert it to a dance floor, the room is at first way too hot and humid. You have to extract the moist air and the chlorine-related smell. The floors take about five to 10 minutes to lift, but the air handling takes more time.”

Williams, who works with interior designers to create his hybrid rooms, adds: “When it comes to decoration, there are things you can’t have: standard electrical sockets or soft furnishings. Wallpaper. But we find these rooms tie in well with the interior design of the houses where we install them. The clients tend to like hard surfaces such as stone and finished concrete throughout the home. They look great and are a good fit with the swimming pool, although they make for challenging acoustics.”

To one family, acoustics were of paramount importance. Margaret Lewisohn, a piano tutor, and her husband, Oscar, chairman of a financial services firm, built an indoor pool that transforms into a rehearsal space for Margaret’s 50-strong youth orchestra, Marryat Players. “We decided to build a swimming pool in the garden, but then we heard about this mechanism of a moving floor and decided to find out more,” she says. After some research, they commissioned London Swimming Pool Company to fit the 12m by 5m pool (similar projects price on request), using FT Leisure to supply its Aquaterr moving floor. Their pool pulls off a particularly effective disappearing act once the floor is raised, as the interior decor is not dominated by the traditional shiny tile or stone finishes. The walls were clad by architect Michael di Marco in Brazilian Virola plywood, and the floor is layered with natural-fibre rugs in neutral colours. “We had wall hangings made as well,” says Lewisohn. “Beautiful botanical patterns by Clarissa Hulse, padded to absorb some of the resonance.”

As these pools are commissioned in increasing numbers, homeowners desire features that make their projects unique, and designs are becoming ever more extravagant. “We are entering a period of property developments where the sky is the limit,” says Alan McVitty, director of McVitty Interior Consultants (projects price on request). He recently oversaw the construction of a spectacular 26,000sq ft mansion on Surrey’s Wentworth estate for a couple who plan to entertain their large circle of family and friends on a grand scale. In the basement spa area McVitty devised a dazzling new spin on the disappearing pool. “We incorporated an etched-glass dance floor, which lies at the bottom of the 5m by 14m pool and is then floated to the surface. The pool has colour-changing lighting, which illuminates the glass. In addition, over the Jacuzzi, a glass floor can be lowered from the ceiling to increase the floor area. The ceiling itself has thousands of fibre optics, creating a night sky.” Now that is one astronomical party piece.

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