Twenty-five villas illegally built on top of a shopping mall in Hengyang, Hunan province, have remained there for at least four years despite a demolition order from the city government. [Chinanews.com]

The developer who built 25 villas on the roof of a shopping mall in Hunan province without government approval will not be allowed to sell any of the properties.

The villas, which cover approximately 20,000 square meters of Wings Housing Plaza in Hengyang, have been under threat of demolition on several occasions from the city administration, urban planning and fire departments. But developer Hengyang Wings Group Co never followed through with the orders.

The city government has now ruled that the villas can remain but must not be sold.

The villas were built in 2009 atop the four-story construction materials and furniture mall, according to blog posts last week by Chinese netizens on Sina Weibo, China's version of Twitter.

Each villa looks identical, with a blue roof and yellow exterior paint. Most have large porches and cement yards divided by white picket fences dotted with bushes.

Even after construction was completed, the developer did not apply for a construction project planning license and a sales permit from the local government, Wang Jianxin, the developer's general manager, told the Morning Herald, a newspaper in Hunan.

"The houses are now dormitories for our employees. Some migrant workers who took part in the villas' construction are also living in them," he said.

Employees at the developer's sales office confirmed the villas are not for sale.

An official with the urban planning bureau, who refused to be named, said the city government is aware that the villas were constructed without their approval and has been discussing what to do with them.

He said the bureau had ordered the Wings Group to demolish the villas, but that the company had simply ignored the request.

Wang explained that the company did not demolish the villas because the mall's fourth-floor tenant Easyhome, a Beijing-based furniture retailer, believed this would damage the mall's structure.

Fu Honggang, director of the urban planning bureau in Shigu district, where the shopping mall is located, said he is not familiar with the case, adding that "the matter has been dealt with by the city government for many years".

A construction expert with the China Academy of Building Research who refused to be named said that if there is any structural change to a large building, "the developer must have architects survey the structure and calculate the load that could be afforded by the building".

"If the plaza's structure is proved strong enough to hold the villas, then you don't have to demolish them. Otherwise, the weight of the houses will be hazardous to the whole building," the expert said.