The National Building Museum has begun a three-month closure so its Great Hall can undergo repairs.
The U.S. General Services Administration will replace the museum's concrete floor with a modern foundation. After construction, the museum will be much easier to navigate, according to a press release.
The museum is closed as of Monday and isn't expected to reopen until March 2020.
The structure opened in 1885 as the United States Pension Building. When it was converted to a museum, a mandate required the historic architecture be preserved.
"It was a difficult decision for the Museum to close its doors, even for a short period," Chase W. Rynd, executive director of the National Building Museum, said in a statement when the decision was announced. "This is a necessary investment in our historic building's infrastructure."
The museum already has a slate of programming planned for when it reopens in spring, including an exhibit on the border wall from the perspective of design and architecture.