Londoners Are Adding These Hidden 'Sinking' Pools to Their Gardens — But Are They Actually Worth It?

It's around this time of year when the idea of having a pool in your backyard feels intoxicatingly appealing. In this seemingly never-ending heatwave of a British summer, there is nothing I'd like more than to plunge myself into an icy body of water every couple of hours. But, for most of us Londoners, a garden pool feels about as realistic as getting a tube seat in rush hour.

There are a few reasons behind this. First of all, despite what these past few weeks would have you believe, London weather rarely calls for a swimming pool, and for 80% of the year, it would likely go unused, taking up precious space. Which brings us to the second, and foremost problem: the staggering lack of space. In the capital, you're lucky if you've got a home with a garden, let alone a garden large enough to contain a pool. Even if you were to decide to commit to a swimming pool, it would most likely come at the expense of the rest of your garden, leaving no room for anything else to squeeze into your outdoor space.

It's these reasons exactly that made the reel posted by Charlotte Green, from Sixty3 Design, go as viral as it did. The video starts with Charlotte walking across the paved, London patio garden of a recent design project, and then, with nothing more than a touch of a button, the floor recedes, as if by magic, and gradually fills up with water, leaving a pool where just five minutes prior, there was nothing. It's the ultimate backyard magic trick, and quite possibly, the solution we Londoners have been waiting for.

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Why Choose a Retractable Pool?

How many times have you looked around your tiny garden and questioned whether you could squeeze a pool in somewhere? It's something I've done more times than I'd care to admit. Though my conclusion is typically that I'd have just enough space for a children's paddling pool, if I squished my outdoor dining setup together a bit.

What I'd never considered, though, is the idea that I could fit a pool in, right beneath my feet, without having to sacrifice any of my garden's usable floorspace.

Urban gardens are hard to come by, so even the smallest gardens have to be savored and celebrated, designed to get as much out of the space as possible. "London gardens are incredibly valuable spaces, and most clients want somewhere that works just as well for entertaining as it does for family life," explains Charlotte. It was with this in mind that she began exploring the option of a retractable pool for this project.

At floor level, the raised pool functions exactly like a normal deck, providing additional space for any typical garden activity. But, once lowered, Maxime Carpentier, director of Akvo Spiralift, says, "It functions as a normal swimming pool, with users typically unable to notice that a movable floor is installed beneath them. The system also allows the pool depth to be adjusted to suit different activities, making it a versatile solution for the entire family."

Unlike a traditional pool, which can easily dominate the majority of the garden and will likely sit unused for months at a time, this type of pool adapts to suit your needs. "When closed, the garden functions as one large terrace for dining, children's play, and entertaining," says Charlotte, "At the touch of a button, it transforms into a fully functioning swimming pool."

By allowing you to maintain one consistent patio flooring finish, you can create a cohesive and balanced design while still benefiting from the addition of a pool. It's particularly useful for small gardens, where you still want to be able to use it for various functions. "As designers, we're always looking for solutions that maximize every square meter without compromising on aesthetics, and this was the perfect example of that philosophy. We thought the retractable design was so clever," says Charlotte.

What You Need to Know

I'm sure, for many of us, this feels like the ultimate win-win. All the usable garden space you need, with the hidden surprise of a pool waiting for you at the touch of a button. What's not to love? But, as smart as this design is, there are some details you should know before you dive into the deep end.

First of all, perhaps the most pressing question: how does this even work? Well, as Maxime explains, "A movable pool floor operates much like a piston within a sleeve. The floor is raised or lowered inside the pool while water flows freely through small gaps around the perimeter, allowing the water level to remain constant and fully within the shell." There are, he adds, a few different methods to achieve a movable pool floor. The most common are "mechanically driven floors, which are raised and lowered by a system of lifting mechanisms, and buoyant (floating) floors, which are guided downward using a hydraulic system and rise naturally through buoyancy."

Of course, a swimming pool is never going to be a cheap home addition (even a small backyard pool can cost a pretty penny), but with a retractable design like this, you can expect prices to be significantly higher. This will largely come down to the costs of installation, as you'll have to work with a team that specializes in this style of swimming pool. "It's a far more specialist installation than a conventional swimming pool because the engineering and precision are absolutely critical," explains Charlotte.

Given the nature of this design, your pool must be considered in relation to the rest of your garden at every step. Every hardscaping material and detail you choose will have to be considered accordingly, which can be tricky if you don't have the right team to help you through the process. "The structural coordination, waterproofing, mechanical systems, and finishes all have to work seamlessly together," agrees Charlotte. "Fortunately, our clients worked with experienced specialists, and the process was very smooth, but it definitely isn't something you'd want to attempt without the right team."

However, Maxime does note that there is a surprisingly large range of flooring materials that can be used with this kind of system: "Our floors are custom-designed for each project, allowing us to accommodate virtually any finish material approved by its manufacturer for submerged applications."

The bigger consideration, he says, is the issue of water treatment systems: "We generally do not recommend the use of salt chlorinators, as the chlorination process introduces electrical currents into the water that can significantly accelerate corrosion of metallic components." Instead, Maxime recommends alternative solutions, such as "UV disinfection, ozone treatment, and automatic liquid chlorine dosing systems," all of which can maintain high-quality water as well as lower chlorine levels and avoid the risk of corrosion.

Despite how simple it may look in the video, the reality behind this design is far more complex than you may think. Because the pool is fully integrated into the garden, all the rest of your planning decisions will have a direct impact, so plenty of forethought and thorough planning are absolutely essential. In fact, Charlotte says, "I think people often underestimate how much planning needs to happen before installation begins. "

The pool is just the tip of the iceberg, she says, explaining, "Our team was responsible for choosing the garden paving, the outdoor kitchen, and furniture, as well as the finishes for the back elevation of the house. Lighting, drainage, landscaping, access for maintenance, and the surrounding materials all need to be considered from the outset to ensure everything integrates beautifully."

With this in mind, Charlotte strongly recommends working closely with a professional designer. Without an expert's opinion at hand, it can quickly all start to feel rather confusing.

Are They Worth It?

Now, onto the real question: are these designs actually worth it?

"For most residential projects, the primary consideration is budget," shares Maxime. "A movable pool floor provides exceptional safety, flexibility, and additional usable outdoor living space, but it is also a significant investment." On average, you can expect a design like this to cost upwards of £150,000, with larger, more extravagant designs costing anywhere between £300,000 and £700,000, with Maxime noting that some designs can even creep towards the millions. Not a budget option by any means.

If you are in a position to spend this kind of money, though, what you'll want to think about is what exactly you want to get out of your garden. Is your garden primarily an entertaining area, or is it a space for your children to play around? These details can help you identify whether or not this type of pool will be a beneficial addition for you.

The most appealing element of these designs comes from the options they open up for your outdoor space. "A retractable pool isn't simply a luxury feature; it's a way of making one outdoor space perform multiple functions," explains Charlotte. "If you're short on space, particularly in London, that flexibility can completely transform how a garden is used."

It's also important to consider the costs that come after the initial installation, too. Though they're unlikely to be quite as high as that initial sum, the cost of maintaining and looking after a pool of any kind will always be relatively expensive, as they require consistent, specialist care.

With all this in mind, Charlotte still believes that "for the right project, I think the benefits far outweigh the additional investment." Not just a regular pool, these designs transform how your garden is used. "You effectively gain a usable terrace garden and a swimming pool within exactly the same footprint, which is incredibly valuable where outdoor space is at a premium," says Charlotte — and I can't say I disagree.

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Even if a retractable swimming pool of your own isn't on the cards for now, there are still plenty of other ways you can get the luxurious dip you've been dreaming of this summer. In fact, our lifestyle editor, Gilda Bruno, has just curated the ultimate guide to the best London hotels with pools, so the hard work is already done; all you need to do is dive in.

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