It’s the world’s tallest prefabricated building, Broad Sustainable Building’s 57-story tower in the suburbs of Changsha, the capital of Hunan Province. The city’s claim to fame is that Mao was born nearby, but other than that, it’s well, provincial. 

The building, called BSB for short, is a tremendous accomplishment, rising at three floors a day. The floor plates come out of the factory with mechanical systems, plumbing and finishes all installed, hauled up by one of the giant cranes and bolted into place. Broad started as an air-conditioning company, so the systems are among the best in the world, delivering air with particulates reduced 99.9 percent (which you really need in China, even in the suburbs of Changsha). Eight inches of insulation and quadruple glazing make the building 80 percent more efficient than conventional buildings. It is healthy, green, fast and affordable construction.

So why hasn’t this technology taken over the world, or at least China, or even Hunan Province?

It’s an interesting question. I've been covering BSB for a number of years. I've been a huge fan of it, and have written many posts with headlines like One Building, One City: World’s tallest prefab, Sky City, is breaking ground in June — though that headline never actually turned out to be true.

In 2013, I visited the site of Sky City, what was going to be the tallest building in the world at 220 stories. Workers broke ground on it and were getting ready to dig the foundations when the government stepped in, ostensibly questioning the technology. Broad’s chairman, Zhang Hue, was vilified in the Chinese press to the point that he issued a public response, which we published on TreeHugger. They called him a “bogus environmentalist” and worse.

Site of Sky City, the world's tallest building, in China

Site of Sky City, the world's tallest building. (Photo: Lloyd Alter)

In fact, it appears that the government simply didn’t want the tallest building in the world built in the middle of nowhere outside a small (only 11 million people!) provincial capital. So it is still a hole in the ground.

Meanwhile, back at Broad Town, there are a lot of workers needing housing and an opportunity, so BSB started building a 97-story version of Sky City. The project was under construction (I visited again last March), going up three stories a day when the government shut the whole project down. Months were lost while the authorities complained about the danger to air traffic, building such a tall building so close to the airport. (It’s a half-hour drive from Broad Town to the airport.) The building was cut back to 57 floors, which is how it stands today.

It's often a problem when new technology disrupts the system, and BSB’s building system is incredibly disruptive. In China it seems that half the country is building apartment buildings and the roads and trains that connect them, and the other half of the country is speculating in them. The tall towers are built in almost the same way as a farmer’s house in the country: concrete  slabs with brick walls covered in ceramic tile from scaffolding that surrounds the whole building during construction. It’s labor-intensive, employing millions, which is probably just fine with the government. Air quality and environmental concerns are irrelevant; just throw in a mini split AC unit and you’re done. 

Dancing for the buyers at Broad Town.

Dancing for the buyers at Broad Town. (Photo: Lloyd Alter)

Meanwhile, back at BSB headquarters, the hotel is full of buyers from the Middle East and other Asian countries looking at the technology and negotiating licenses, while being entertained by the talented Broad employees in the evening. 

Chairman Zhang told me that the market for BSB would be in the developing countries like Brazil and India where there are millions of housing units needed. But I suspect that just like North America and China, it will a tough battle there too. Construction remains labor-intensive, one of the few blue collar manufacturing jobs still left. 

Broad Sustainable Building is really on to something here. But there is no industry in the world as entrenched in its ways as construction is. The problem here isn’t technical; it’s political. And it’s too bad. 

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Lloyd Alter ( @lloydalter ) writes about smart (and dumb) tech with a side of design and a dash of boomer angst.