美国国家公共电台 NPR--3D打印房屋可能是建筑业的未来（在线收听）

3D printed houses may be the future of the construction industry

Transcript

Affordable housing advocates say 3D printed homes could be a game changer, but so far they haven't proven cheaper to build than conventional houses.

A MARTINEZ, HOST:

The White House says the U.S. currently has a housing shortage of about 4 million homes. There are a lot of reasons for that. But in some places, houses just can't be built fast enough. Habitat for Humanity thinks giant 3D printers could make a difference and has now built its first two 3D-printed homes in the U.S. From member station KJZZ in Phoenix, Katherine Davis-Young reports on their potential.

KATHERINE DAVIS-YOUNG, BYLINE: Shawn and Marcus Shivers are thrilled to be moving into their first home. The most exciting part is that it's right in the heart of Tempe, Ariz., where they raised their three sons.

SHAWN SHIVERS: We've both lived in this area our whole life, so we were born and raised here.

DAVIS-YOUNG: But by the time they saved enough to consider buying a new home, they really didn't think they'd be able to afford to stay here. The Case-Shiller Home Price Index shows home prices are rising faster in the Phoenix metro area than anywhere else in the country - up 32% just in the last year. Experts say part of the reason is Phoenix hasn't built nearly enough new houses to keep up with explosive population growth over the past few decades.

(SOUNDBITE OF MACHINERY WHIRRING)

DAVIS-YOUNG: The Shivers family got lucky and are buying their house with the assistance of Habitat for Humanity. That means they're helping out with the construction. But the walls of this house are being built with a 3D printer. The printer moves a steel rail back and forth between columns that straddle the building site. Following automated plans, it lays a line of wet concrete a few inches thick as it goes. Then it coils one layer on top of the last, building up the interior and exterior walls of the 1,700-square-foot three-bedroom. Next, workers add a traditional wood-framed roof.

(SOUNDBITE OF HAMMER BANGING)

DAVIS-YOUNG: When they applied for a Habitat home, the Shivers had no idea their family would end up in one of the first 3D-printed houses in the U.S.

S SHIVERS: At first, I wanted it for sure because it was so innovative and new, and he was kind of skeptical because he's...

MARCUS SHIVERS: I mean, I have to worry about, you know, internet, plumbing, electricity. Who's going to come and fix it? I mean, after seeing it now though, I'm a lot more comfortable. It's actually beautiful.

DAVIS-YOUNG: Debra Bradley with Habitat for Humanity Central Arizona says she hopes this technology will help the organization meet demand faster in the future.

DEBRA BRADLEY: You know, if we can get down to where we can build a house in seven or eight hours, the exterior of the home, and the cost makes sense and the product is stable and long-lasting, then why wouldn't we do that?

DAVIS-YOUNG: Only a handful of 3D-printed homes have been built nationwide. Habitat has only built one other, in Virginia. And right now, the technology is still too new to be cost-effective, says Mark Stapp. He's a longtime developer and director of the real estate program at Arizona State University. Stapp says framing a traditional house might only come out to 15% of the overall cost. So when it comes to 3D printing, he doesn't expect concrete would reduce the price of materials all that much.

MARK STAPP: We don't have sufficient amount of experience in order to be able to scale this and get the cost savings that people would hope.

DAVIS-YOUNG: But he says 3D printing could reduce labor costs significantly and help in places where there's not enough labor available, like in Phoenix. Stapp says he could see it making a difference maybe five years down the road.

STAPP: It absolutely has potential.

DAVIS-YOUNG: There are obstacles, though. Tempe has no building codes to address 3D-printed homes, which made permitting a challenge. But Habitat for Humanity's Debra Bradley says even if the organization's first 3D-printed home in Arizona came in over budget and behind schedule, the point was to show it can be done.

BRADLEY: And now we can take this and prove to the world we can do things differently and have a better outcome.

DAVIS-YOUNG: She says change has to start somewhere, so why not start with the Shivers family with their first home in Tempe?

For NPR News, I'm Katherine Davis-Young.

(SOUNDBITE OF REUBEN VAUN SMITH'S "UNDER THE THUNDER")