"It exceeds expectation," The Daily Campus student newspaper quoted Bush as saying at a topping-out ceremony marking the placement of the final beam atop the center's Freedom Hall in Dallas on the Southern Methodist University campus. "It's going to be a fabulous addition."
Besides serving as a museum dedicated to Bush's two-term presidency, the building will house offices for him and his wife, the newspaper said.
Project architect Robert Stern said the center will qualify for a Leadership in Energy and Environmental Design platinum rating because of its environmentally friendly and energy-efficient design.
Former first lady Laura Bush said they were "very excited" that the project is utilizing many local materials. The landscaping will include trees from the family's ranch in Crawford.
"We're very excited to be using so many local materials," Laura Bush said, adding that her favorite part of the center will be the landscaping.
The Bushes said they intend to have ongoing roles at the center.
"The challenge after you're president is to make sure you're still constructive," George Bush said.
The millions of pages of documents from the Bush administration will aid academic research when it opens in the spring of 2013, officials said.
"The center will serve as a gateway for scholarly discussion and debate," said Mark Langdale, president of the George W. Bush Foundation.