China's city in the sky: just a fantasy?

Zhang Yue feels misunderstood.

He shouldn't be surprised. It is not easy to fathom how and why the tycoon intends to erect the tallest building in the world in less than 12 months in a field outside this provincial capital in southern China.

There are, as Regina Yang, head of China research for property consultants Knight Frank, says, "a lot of questions about this project."

Since the groundbreaking ceremony for Sky City last month, Mr. Zhang's unprecedentedly ambitious plan has attracted scorn and skepticism at home and abroad as a fantastical vanity project by a newly rich billionaire.

But Zhang, sitting behind a desk cluttered with piles of architect's drawings and engineering plans, insists that his vision of a city in the sky – a vertical community of 30,000 people – has nothing to do with vanity.

Using novel technology, he explains, "this is practical architecture ... to build housing for ordinary people in urban areas," curb urban sprawl, and save energy, all at the same time.

"This is a tall building unlike any tall building before," says David Scott, a director of the engineering excellence group at the British construction company Laing O'Rourke, who has studied the project. "Its clear focus is on trying to find a solution to create megacities."

But local authorities, who had been enthusiastic about Zhang's dream, appear to be having second thoughts. As new President Xi Jinping tries to discourage ostentation and reward frugality, a world-record skyscraper would be out of sync with the official mood.

State media have reported that Zhang is still waiting for some of the permits he needs, though local officials refuse to comment on those reports and Zhang himself says he is plowing ahead. But work has been sluggish at the site since the groundbreaking.

There is no denying Zhang's extraordinary vision: The plans pinned all over his office show a 202-story, 2,723-foot stepped tower (32 feet taller than the Burj Khalifa in Dubai, United Arab Emirates) that would contain "anything you need from cradle to grave, except a crematorium," as Zhang puts it.

Road to the 170th floor

That means schools, a hospital and retirement home, a theater, shops, restaurants, cinemas, sports facilities, parks, and vegetable farms, even a road to the 170th floor, along with a hotel, offices, and 4,450 apartments.

Even more astounding, Zhang says the whole thing will be ready for occupancy within 12 months, less than a quarter of the time it took to build the Burj Khalifa, and cost one-fourth as much, with a budget of $1.5 billion, though he will not identify his investors.

That is possible because of the "plug and play" construction that Zhang's company, Broad Sustainable Building, has developed.

In a factory 90 minutes' drive north of Changsha, workers assemble prefabricated boards, each comprising a floor and a ceiling. The floor is tiled, the ceiling is drywalled, and between them the building's electrical, plumbing, and other facilities are installed. These boards are simply transported to a construction site, hoisted up, and bolted one to the other. Then the walls and windows are attached.

Broad built a 30-story hotel in 15 days using this technique. A model of the T-30 hotel withstood the equivalent of a magnitude-9.0 earthquake, and the heavily insulated building – equipped with Broad's heat-exchange nonelectric cooling system – uses one-fifth the energy of a traditional structure of its size, the firm says.

Sky City "has a lot of engineering and trial and testing behind it," says Mr. Scott, whose company is planning to construct a 50-story hotel in 50 days using similar techniques.

'This is for real'

The Chicago-based Council on Tall Buildings and Urban Habitat, the world's arbiter of skyscraper-related issues, gave Broad Sustainable Building its 2013 Innovation Award last month, and a CTBUH delegation came away from a visit to T-30 last year "suitably impressed and feeling that this is for real," recalls Daniel Safarik, the CTBUH spokesman.

"The question is not whether they can do it," Mr. Safarik says of Sky City. "The deeper question is whether it is reasonable or advisable. What would these hermetically sealed, all in, self-contained vertical cities mean for the way we live?"

Zhang envisages 30,000 people occupying Sky City and predicts that there will be 10,000 jobs in the building itself, with the offices, shops, farms, and other employers.

"We want people to walk to work or school or to have fun," he says, since most residents would never need to leave the building.

The concept echoes Utopian visions dating back five centuries to Thomas More, as well as more recent experiments.

"It is almost nostalgic for an old modernist ideal that Western architects were exploring in the 1960s," says Ryan Smith, an architecture professor at the University of Utah in Salt Lake City. "But this is not the future of buildings."

"Most people want to live near the earth, close to trees and flowers," adds Mao Qizhi, deputy dean of the school of architecture at Tsinghua University in Beijing. "A lot of high-rise buildings cause a lot of problems for the people living in them."

Zhang says he thinks a good view is more valuable than proximity to the ground, but he acknowledges that in a self-contained community as large as Sky City "social problems are possible." He adds, "I can't solve them."

Battered from all sides, Zhang says he feels "bad and disappointed ... that no one is looking at the environmental protection" the building represents, or its "potentially monumental influence on human social development."

The negative comments, he worries, have spooked local authorities, whose permission he needs.

"The more the media talk about us," he says, "the more slowly the government will deal with the permits."

But he says he is confident that "in a year's time, people will be moving into the tallest building in the world."

That is a pipe dream, says property consultant Ms. Yang.

"If this building is finally built," she scoffs, "it will be a miracle."

Perhaps both of them are right?