Photo provided to China Daily

Hu is paid about 6,000 yuan ($962) a month, and his wife, an office building lobby cleaner, is paid about 4,000 yuan. This allows them to rent a 40-square-meter apartment at the foot of Xupu Bridge in eastern Shanghai. The rent is 1,100 yuan a month, and Hu says he usually sends 1,000 yuan a month to his parents, which he says is not too burdensome.

In 2011, Hu managed to buy a 90-square-meter apartment in his hometown that is valued at more than 450,000 yuan. And he is proud to say he paid for it without having to borrow money.

"I thought of buying an apartment in Shanghai. But house prices here are too intimidating. A 50-square-meter apartment can set you back as much as 1.4 million yuan."

Hu says he dropped out of school when he was still in senior high as his family could not pay the school fees. But he says he and his wife have not set ambitious targets for their son.

"It does not matter if he excels at school or not. It's good enough if he tries his best. It is hard to say if a person who stays at school for years will eventually succeed. But you can be sure of one thing: anyone who drops out early is unlikely to do well."

Hu says that since his job is demanding physically, he spends most of his free time at home.

"Reading the Bible is my favorite pastime. It gives me peace and wisdom. It is awful when people don't believe in anything. You can easily feel lost. I go to church on weekends. But more often, I listen to the minister preach online, which is very helpful."

Hu has also thought of traveling overseas, but he is not sure where to go.

"If I ever do go overseas or meet a foreigner in Shanghai who asks what I do for a living, I will happily tell him I am one of those who helps keep the tallest building in China looking brand new."

However, Hu is now approaching 45, the legal retirement age for skyscraper cleaners, so he is starting to think what comes next after being spiderman.

"I may start my own business, like running a small restaurant selling local specialties. But I have not thought it through yet," he says.