Buoyant buildings: better than boats?

With hurricane season at its peak, we explore how floating homes might help us adapt to bigger storms and rising seas.

The Dutch have a head start when it comes to dealing with water. The extreme weather events and rising sea level that scientists predict this century will affect millions around the globe—most of the world’s largest cities are along the coasts. But that problem has long been acute in the low-lying Netherlands, where two-thirds of the population live in flood-prone areas. Over the centuries, the Dutch have honed technologies—dikes, canals, and pumps—that keep their streets and houses dry.

Now, a new generation of Dutch engineers and architects is modeling another method. Rather than fight to keep water out, they say, why not live on it? The basic idea is not new—hundreds of free spirits live on traditional houseboats in quirky communities like Sausalito, California, and Key West, Florida. But in the Netherlands over the past few years, novel technologies have allowed developers to build roughly a thousand (and counting) stable, flat-bottomed, multi-story homes connected to land-based utilities yet designed to rise and fall with the tides and even floods. House boats, these ain’t.

And this is just the start. The Dutch are thinking bigger, and they’re exporting their floating-home vision worldwide, betting that the rest of us coastal clingers could use it. Some projects exist already, others are on the drawing board or coming soon. Let’s take a look at a few, from the workaday to the fantastical, and from overseas to right here in the States.

Photo by Roos Aldershoff, courtesy of Marlies Rohmer Architects and Urbanists


A “normal house” on water

The first of its kind, Waterbuurt (above and top) is a planned neighborhood of about 100 (eventually 165) floating houses in Amsterdam’s IJmeer Lake, part of a freshwater reservoir dammed off from the North Sea in the 1930s. Waterbuurt broke ground—er, water—in 2009, and was largely complete by 2014. Connected by jetties, the structures are three-story, 2,960-square-foot houses built of wood, aluminum, and glass.

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Source: DigitalCommons@CalPoly (colorized for clarity)

And the foundations? Floating concrete tubs. Each house is designed to weigh 110 tons and displace 110 tons of water, which—as Archimedes could tell you—causes it to float. (The bottom floor is half submerged.) To prevent rocking in the waves, the house is fastened to two mooring posts—on diagonally opposite corners of the house—driven 20 feet into the lake bed. The posts are telescoping, allowing the house to rise and fall with the water level. Flexible pipes deliver electricity and plumbing.

Because any crack in the foundation tub could cause the house to sink, there can’t be any joints; builders pour the entire basement in one shot—much like the parking garage of the Jade Signature condo complex in Florida. In a facility 30 miles away from the IJmeer Lake site, crews use special buckets that pour 200 gallons per minute to finish all four walls and the floor in a single shift.

Just four months elapse before the entire house is built; then it’s towed by tugboat—30 miles through canals and locks—to the plot. The transportation is a major reason the houses cost about 10 percent more than an average home in Amsterdam, though they’re still aimed at the city’s middle class. The houses were designed by architect Marlies Rohmer, for developer Ontwikkelingscombinatie Waterbuurt West.

Once secured to its mooring posts, the structure is formally considered an immovable home, not a house boat. (Although owners have the option of naming their waterborne homes as sea captains do. One couple calls theirs La Scalota Grigia—Italian for “The Grey Box.”)

With high ceilings and straight angles, a house in Waterbuurt “feels like a normal house,” wrote a New York Times reporter who toured one. But some residents say they do feel their home swaying when the wind kicks up.

One other drawback, or at least challenge: Residents have to decide before the house is even built where they’re going to place furniture, because that will affect its balance. The walls are built to varying thickness, depending on the layout submitted. What if you inherit a beloved aunt’s piano after you move in? Or have another child and need to buy a bunkbed? To compensate, homeowners can install balance tanks on the exterior or Styrofoam in the cellar, or carefully move furniture around or even deploy sand bags. A bit of a hassle, but perhaps with an eye on rising sea levels, that’s a risk Amsterdammers are willing to take.

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Rendering courtesy of architect Koen Olthuis, Waterstudio.NL, and developer Dutch Docklands

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