The tallest hall in the Forbidden City in Beijing is barely recognizable behind the mesh of scaffolding.

Renovation works on the Hall of Supreme Harmony, China's tallest timber palace building, are expected to restore the hall's former glory during the Qing Dynasty (1644-1911), according to Jin Hongkui, the palace's deputy curator.

Some of the things that need repairing include eaves that are beginning to hang, rotting wood columns, broken glass tiles, and ceramic tiles that need re-glazing.

The Hall of Supreme Harmony, China's tallest ancient timber palace building, was closed to the public in January. Workers are overhauling the outer and inner portions of the hall. A work-in-progress review will be conducted by experts in June, Jin said.

The renovations are scheduled for completion in two years.?

Located strategically along the vertical axis of the Forbidden City, the hall was used for grand ceremonies such as enthronements, weddings, birthdays and the Chinese Lunar New Year among other important festivals.

The hall was originally completed in 1420, but has been rebuilt several times over the years due to damage caused by fire.

Examination and planning works for the hall's renovation began in 2004, according to Jin, which included literature research and collecting. Professionals combined manual mapping, three-dimensional laser scanning and wood survey technologies to analyze the structure and condition of the hall.

Experts from the Italian Cultural Heritage Department also contributed to the work of pollutant analysis and tested refurbishment materials, using their experience of renovating ancient architectures in Europe, Jin said.

He said the main structure of the hall is basically stable. But parts of the wood frame, ornaments, walls, roof tiles and the unique brackets that stand atop columns are damaged to varying degrees.

Further, the paintings on the outer eaves were not done in line with the original design during previous renovations, he added.

The Forbidden City, also known as the Palace Museum, in central Beijing, was the power center of the Ming (1368-1644) and Qing (1644-1911) dynasties from 1420 to 1912.

The labyrinthine complex, formerly home to 24 emperors, their families and courtesans, and reputed to have 9,999 rooms, is one of China's best known icons and most popular tourist attractions. Seven to eight million tourists visit it every year.

UNESCO listed the Forbidden City as a World Cultural Heritage Site in 1987.

General renovations, which started in 2002, will take more than 10 years to complete and will cost of over 2 billion yuan (US$250 million).

As at the end of 2005, about 38,000 square meters of ancient architecture had been repaired, at a cost of more than 200 million yuan (US$25 million).?

(Xinhua New Agency March 29, 2006)