The Chicago Tribune reported Wednesday that the architects of the Obama Presidential Center said the former president found an early concept “too quiet” and speculated that the library could end up costing $1.5 billion.

The architects were interviewed at an event held last week at New York’s Lincoln Center:

Interviewed by Paul Goldberger, the New York architecture critic who advised the Obama Foundation on the architect selection process for the library, Williams and Tsien revealed conceptual ideas for the project, said Obama critiqued an early plan of theirs as too quiet and speculated that the library could require a whopping $1.5 billion to cover construction, endowment and other costs.

The Chicago Tribune noted that Tsien was also quoted by architectural website ArchDaily as saying that Obama found the preliminary design for the project “too unflashy.”

“He looked at what we did and he said, ‘I said you could be sort of quiet, but I think you’re a little too quiet,'” Tsien said.

There are more details about the center here, which is planned to house a museum, archives, and community organizing gathering spaces:

Obama’s legacy might require more than just a library: