A building’s skin and bones—literally? The coming world of engineered living materials

When lightning strikes, a tree can often repair the damage by generating another layer of bark to cover the gash. But if that same bolt from above lashes a wood-frame house instead, call the remodelers. Even though the house’s exterior walls are essentially made of trees, the material lost its adaptive quality when lumberjacks felled those mighty pines or oaks.

In the words of scientist Justin Gallivan of the U.S. Defense Advanced Research Projects Agency (DARPA), wood is “rendered inert” when a tree is chopped down. That neutralizes all the advantages of a living material. In their natural state, trees react and adapt to wounds and the weather. So do coral reefs—not to mention your own skin.

What if living materials, with those same self-healing properties, could be grown artificially to the size and strength required to construct a house? Or a skyscraper? Is that possible? That’s what DARPA wants to find out. The agency is soliciting research proposals aimed at the creation of what it calls “engineered living materials (ELM).”

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DARPA envisions walls that fix themselves, non-fading surfaces, and driveways that absorb oil spills without a trace. (Source: DARPA)

“Imagine that instead of shipping finished materials, we can ship precursors and rapidly grow them on site using local resources,” Gallivan said to the press in August when announcing the ELM program. “And, since the materials will be alive, they will be able to respond to changes in their environment and heal themselves in response to damage.”

Today, a building’s envelope is often called its “skin,” while the steel frame of a building is known as its skeletal structure, or even its “bones.” In DARPA’s imagined future, these terms will cease to be merely rhetorical. And the sustainability benefits of bio-building might be substantial, when you consider the carbon emissions generated in the production of conventional materials such as concrete.

But DARPA didn’t pull this sci-fi-sounding concept out of thin air. Biochemists and engineers around the globe are already tinkering with limited forms of biomimetic (or life-imitating) materials, as you’ll see below. Gallivan’s vision of self-healing living walls is perhaps the logical extension of these various technologies, and the ELM program might prove the catalyst needed for skin-and-bone to replace brick-and-mortar.

Bacteria brickyard

One inspiration for the ELM program is a start-up that grows bricks in a lab. Yes, grows. The idea occurred to architect Ginger Dosier when she learned that coral polyps—tiny marine animals—create the hard, rocklike substance sandstone naturally. She co-founded the company, bioMASON, with her husband, Michael—like her, an architect and a self-taught scientist. (They have help from a staff of college-taught scientists.)

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The lab-grown bricks. (Source: bioMASON)

In their lab in North Carolina’s Research Triangle, the bioMASON team places sand into molds and injects it with trillions of microorganisms (Sporosarcina pasteurii, if you must know), which they feed water and a calcium solution. The bacteria bind with the grains of sand, generating a natural cement that becomes heavy and hardens. The bricks are ready in two to five days.

Compare that with the way traditional bricks are manufactured, by digging up clay (which could be better put to use in agricultural soil) and firing it in a kiln at 2,000 degrees for three to five days. This process uses up lots of fuel and releases carbon dioxide into the atmosphere—800 million tons of it per year, by some estimates. Keep in mind, brick is still the most common building material worldwide, with Asia alone making 1.2 trillion bricks a year.

According to Acorn Innovestments, which provided bioMASON with seed funds, third-party testing determined that the bio-bricks have a strength comparable to traditional masonry, though for now, the start-up is only selling the bricks for use in paving. The bioMASON lab can produce 1,500 bricks a week, and they’re moving next month to a larger facility that will enable them to make 5,000 bricks every two days.

But the Dosiers hope to truly make an impact by shipping the bacteria solution—just one hand-held vial can make 500 bricks—across the globe to builders who can mix it with local sand, whether from nearby deserts (looking at you, Los Angeles) or quarries. Continue Reading ›

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

Continue Reading ›

A ray of sunshine: Solar power makes strides in Florida

Construction is underway on the nation’s first solar-powered town, in a state just beginning to realize its potential.

For a state that gets 230 days of sunshine a year, Florida has long been in the Dark Ages when it comes to solar power. The state ranks as low as 17th in terms of solar energy output, despite ranking third in solar potential. But the outlook for that most obvious of renewable energies seems to be getting, well, sunnier by the day.

This week, Florida’s citizens voted by a sky-wide margin (73 percent to 27 percent) to approve a constitutional amendment that will provide significant tax breaks for commercial property owners who install solar panels. It will also allow leasing of solar energy: Going forward, landlords can sell solar power directly to tenants. Expect to see shiny panels sprout on the rooftops of apartment complexes and big-box stores from Pensacola to Miami.

But one Florida developer is going further than that, aiming to change the home-by-home, building-by-building paradigm. Syd Kitson, the chairman and CEO of Kitson & Partners (and a former Green Bay Packer) is building an entire town that will draw most of its energy from the sun.

Breaking ground last fall, Babcock Ranch sits on 17,000 acres in rural Charlotte County, outside Fort Myers. By 2041, this ambitious planned community will house up to 50,000 residents who can stay cool, reheat chicken, Skype with relatives, and even head to the hardware store with the help of the world’s largest photovoltaic power plant. In Kitson’s vision (see rendering above), this sustainable town’s example might inspire large-scale changes in the way Americans live and work.

A series of hamlets, villages and neighborhoods, Babcock Ranch will have its own schools and a downtown district—already under construction—featuring six million square feet of retail, commercial, civic, and office space. Designed on a smart grid to optimize energy efficiency and lower utility costs, the town will make use of current and emerging technologies such as electric vehicles and solar-powered charging stations. And a system of shared, driverless vehicles will move people and goods throughout town.

Slated for completion next year, Phase 1 of construction includes 1,100 homes as well as the downtown district, which will feature a state-of-the-art wellness center, a market café, lakeside restaurant, and educational facilities, all connected by a system of walking trails.

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Members of the media toured the solar plant at Babcock Ranch on Earth Day in April. (Photo courtesy Babcock Ranch)

The entire development will be powered by the 74.5-megawatt-capacity FPL Babcock Solar Energy Center, being built in conjunction with Florida Power & Light on an adjacent 450-acre site. Excess power collected during the sunniest days will be pumped back into the electrical grid, to be stored for use on overcast days.

During nighttime hours, at least in the short term, the town’s power will be supplied by natural gas. Although natural gas is not a renewable resource, it emits 50 percent less carbon dioxide when burned than coal. Moreover, the new homeowners will also have the option to purchase rooftop solar panels—a process that, presumably, will become even easier thanks to the amendment passed this week.

From an environmental standpoint, these are all encouraging developments, showing that solar’s role is on the rise, and perhaps a more sustainable energy mix is just on the horizon.

This post was a collaboration between Suffolk Construction’s Insurance Coordinator Lindsay Davis and Content Writer Patrick Kennedy. If you have questions, Lindsay can be reached at ldavis@suffolk.com and Patrick can be reached at pkennedy@suffolk.com or connect with him on LinkedIn here and follow him on Twitter at @PK_Build_Smart.