The roof and glass at the main terminal building of Beijing's new airport are being installed, with crews attempting to seal off the building from weather by the end of this year or soon thereafter, the airport's spokesman said on Monday.

"The internal decorations and installation of electromechanical equipment will begin as soon as the terminal building has been sealed," said Zhu Wenxin, the airport's spokesman.

As of the end of September, more than 90 percent of the earthwork had been completed, and 95 percent of supporting projects, such as bridge foundations, were finished, he said.