With China’s property market booming and its cities growing rapidly, it’s common for building owners to add illegal structures to their properties in pursuit of profit. Sometimes this causes deadly accidents. In March, a hotel in Fujian province, in the country’s southeast, that had been illegally rebuilt and was being used as a coronavirus quarantine facility, collapsed. Twenty-nine people were killed and more than 40 others injured . A government investigation found that the building originally had four floors but had been split into seven. The newly added floors were the direct cause of the collapse, the investigation found. Among the most recent cases of illegal modification to emerge is that of a business park in China’s largest city, Shanghai. Tenants of the Boyang Enterprise Business Park, which occupies a former paper mill, say structural alterations to buildings there have led to walls developing cracks and ceilings to leak. Most of the buildings in the park used to be either single-storey or two-storey structures, but some of them were split horizontally when the area was turned into a community for small businesses in 2014, said Zhao Yong, one of the tenants. The alterations added more floors and increased tenant capacity, but also put more pressure on the buildings’ infrastructure. HIV crisis looms on mainland among the young and old For 15 years, Zhao has been running a restaurant out of a street-side building that now belongs to the park. He said the ceiling started leaking when a wooden structure was added to the restaurant several years ago, but the park’s management had turned a blind eye to the problem. “I saw the company altered the park six years ago. A few single-storey buildings were made into two-storey buildings, and a two-storey building has three floors now. With more floors after the renovations, the landlord then asked for a rent increase,” Zhao said. Authorities in China tear down millions of square feet of such buildings every year. According to the Ministry of Natural Resources, local authorities around China tore down a total of nearly 97 million square feet (9 million square metres) of illegal structures in 2015 alone. Examples include self-built suspended balconies, a mansion built on a rooftop, and an aerial corridor added above a pedestrian walkway. How dangerous such alterations are depends on whether a building’s original designer was consulted, Guo Xinming, a construction engineer based in Jiaxing, in eastern Zhejiang province, said. “Did they invite the designer of the original structure for a check? Did they ask a qualified company to design the new floors? … There would be quite big safety hazards if not,” he said. The company behind the Shanghai business park, Shanghai Mingqi Investment Management, declined a request from the Post for comment. Five months after the collapse of the quarantine hotel in Fujian, a restaurant in Shanxi province collapsed in August as an 80-year-old man was holding a birthday banquet inside. Twenty-nine people died and 28 more were injured. The building, which was constructed in the 1980s, had been expanded multiple times over the years, and a new floor with several rooms added, The Beijing News reported. Hong Kong also has a problem with illegal structures added to buildings. These run the gamut from supporting frames for air conditioners, enclosed balconies and signboards on commercial properties to canopies, rooftop structures and basements. Figures from Hong Kong’s Buildings Department from the past 18 years suggest at least one in four properties in the city has unsanctioned features . Additional reporting by Shirley Zhao