Hemeroscopium House in Madrid, designed by Antón García-Abril using sections of concrete irrigation canal
Hemeroscopium House in Madrid, designed by Antón García-Abril using sections of concrete irrigation canal (Roland Halbe) © Roland Halbe

Water. More than 70 per cent of our planet is covered with it and our bodies are about 60 per cent composed of it. Yet in most of our homes this vital element is relegated to taps and drains. (One notable exception is Fallingwater, the 1930s house in Pennsylvania designed by Frank Lloyd Wright, which is built over a waterfall.) Lately, however, more architects have been designing properties in which water is the main feature.

“Water is relaxing, calming and dreamlike,” says Dutch architect Wiel Arets who has designed taps, basins and bath tubs for Italian kitchen and bathroom company Alessi but is better known for cutting-edge architecture that aims to be (in his words) “fun and interesting”. One of his projects that has made a splash is Jellyfish House in Marbella, Spain, completed last year. The white concrete property has a glass-bottomed swimming pool on its roof that cantilevers out over a terrace and driveway. “Passers-by stop in the street and stare, fascinated to look through the glass and see people swimming,” says Arets. “It’s like looking into an aquarium except instead of exotic fish there are humans.”

Fallingwater, 1936, by Frank Lloyd Wright
Fallingwater, 1936, by Frank Lloyd Wright (UniversalImagesGroup) © UniversalImagesGroup

The daring feat of engineering initially raised concerns with local building regulators. “Sixty tonnes of water and another 20 or so of concrete cantilevers out for nine metres. While it was being built, they sent engineers to test that the structure could take the weight without collapsing before allowing us to continue,” says Arets. “Everything was fine, of course. In a way the design is like some of the qualities of water itself – it can be powerful and terrifying or relaxing and enjoyable.”

What is happening below water is also visible from inside the house, through 6cm-thick glass walls. “The children jump into the pool and dive down to wave at their mother in the kitchen and their father sitting, reading on a terrace below. It’s like diving into the sea and exploring over corals. They find it a real thrill,” he says. “The lighting effects are also wonderful. The water filters the strong Spanish sunlight and fills the house and terrace with bright yellow and blue shimmering patterns. At night-time there are lights in the pool, and it glows like a mystical blue moon.”

Jellyfish House in Marbella, Spain, designed by Wiel Arets
Jellyfish House in Marbella, Spain, designed by Wiel Arets (Jan Bitter) © Jan Bitter

Why the name Jellyfish House? “In the beginning, when we were still at the drawing board, I asked the client if there was something he’d never had in a home that he’d always wanted and he said ‘an aquarium’. I went to Japan where I saw aquaria of jellyfish, all different colours, so I suggested something similar,” says Arets. “They liked the idea but in the end decided that, as it’s just a holiday home, it was disproportionate maintenance, so we abandoned the jellyfish idea – although the name stuck – and the idea developed into a swimming pool with glass bottom and walls: a ‘human aquarium’ instead.”

Swimmer in the pool above the terrace area of Jellyfish House
Swimmer in the pool above the terrace area of Jellyfish House (Jan Bitter) © Jan Bitter

Newer technologies mean such pools are more feasible today. “Over the last couple of decades several large aquaria have been built around the world, and glass is stronger and more structural. Glass is one of the most exciting materials to work with and has huge potential for metropolises in the future,” says Arets, who holds the post of dean of the College of Architecture at the Illinois Institute of Technology in Chicago, known for its glass Crown Hall designed by Ludwig Mies van der Rohe in the 1950s. “Also, concrete can now be made much more dense than it used to be, so you can have the same strength of reinforced concrete with less thickness which is more elegant.”

The rooftop infinity pool/human aquarium might never have come about had 59-year old Arets not climbed up to the roof of the previous house that stood on the inland plot. “From the top, I could see the sea and so it made sense to build an upside down house with a pool on the roof so the family can see the Mediterranean and the Sierra Blanca mountain range from their pool and sundeck.”

Another Spanish property in which a cantilevered and glass-sided pool is an outstanding feature is the Madrid family home of architect Antón García-Abril of Ensamble Studio. The house took a year to design, yet only seven days to build using 250 tonnes of girders, beams and sections of concrete irrigation canal (otherwise destined for agricultural purposes), all cleverly balanced on top of each other. A section of irrigation canal, it turns out, makes a perfect lap pool: 1.5 metres wide and 0.9 metres deep, while a 20-metre length cantilevers out from the building, finishing in a glass wall. “It’s like flying while swimming,” says García-Abril, 45, who says he swims in the unheated pool every day between mid-May and mid-September. There is also a ground-level pool around which the family gathers in an outdoor living area, part shaded by giant concrete beams and girders. The blue water adds lightness, fluidity and vibrancy to the heavy monochrome materials.

“Water is very important in our Mediterranean culture – it reflects light and gives colour to space,” says García-Abril.

Shaw House in Vancouver, designed by Patkau Architects
Shaw House in Vancouver, designed by Patkau Architects (Paul Warchol) © Paul Warchol

It is not just in sunny southern Europe that homeowners are building pools in the sky. In Vancouver, Patkau Architects has built Shaw House, which has a 21-metre heated rooftop lap pool with a glass bottom. “The client really enjoys the quality of light the pool effects – sunlight filtering through the water and glass pool bottom into the main floor as well as reflected light from the pool surface into the upper floor. The light changes with the time of day, cloud cover and wind conditions,” says a spokesperson for the Vancouver firm. Such light effects come about as a result of some heavy engineering. “Due to the narrow site, the only location a lap pool would fit was up on the second floor. Because Vancouver is in a high seismic zone this necessitated a robust concrete structure that could handle the eccentric loading a large volume of water held up in the air would place on the house.”

Meanwhile, other architects are developing water features with a more sustainable slant. BIQ House is a prototype “bio-intelligent” apartment block in Hamburg with a façade of water tanks in which air and nutrients bubble through water, feeding micro-algae. Although from inside the 15 apartments, the water tank façade is not visible, there are balconies from where residents can see the sun shining through 2cm of green algal soup sandwiched between glass 3cm thick. “It’s like being in a church and looking up at a bright green, stained-glass window,” says Dr Jan Wurm, associate director of design firm Arup and project director for the development of the innovative façade system. The dark green solution absorbs heat from the sun which is used to heat the apartments’ water supply and the building itself, storing surplus heat below ground for use in winter.

BIQ House in Hamburg features a bioreactor façade
BIQ House in Hamburg features a bioreactor façade (Johannes Arlt) © Johannes Arlt

These living bio-panels are not quite as efficient as standard solar thermal collectors but this is compensated for by their production of algae. This could be harvested, dried and burnt in a biomass boiler, but Wurm suggests that a more energy efficient and cost-effective use would be to harvest it for fish food or as a source of molecular building blocks for use in pharmaceuticals. “The bioreactor façade is really like a vertical pond where we can cultivate things without having to use up space on land,” he says. Two species of algae are grown in the tanks – a warmth-loving one in summer and an Arctic species in winter.

Wurm envisages a future where tanks of algae play an important part in a city’s architecture, harnessing solar heat, capturing carbon dioxide, growing biomass and cleaning grey water. Such innovations might not be as glamorous as homes with glass-bottomed swimming pools, but they’re certainly greener.

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