The National Building Museum announced Friday that the museum will undergo an extensive project to replace the building's concrete floor with a modern foundation.

A D.C. museum will close to the public in December for necessary repairs.

The National Building Museum announced Friday that the museum will undergo an extensive project to replace the building’s concrete floor with a modern foundation. Construction is scheduled to begin Dec. 2 and finish March 2020.

“It was a difficult decision for the Museum to close its doors, even for a short period,” the museum’s executive director Chase W. Rynd said in a statement. “But the scope and scale of this project required us to do so.”

A recent General Services Administration survey found that the original thin concrete slab foundation that was laid beneath the floor in the 1880s, and was supporting the weight of the building, has deteriorated over the past 135 years.

The National Building Museum was chartered by an Act of Congress in 1980. However, the Italianate Renaissance Revival building that houses the museum opened in 1885 as the United States Pension Building.

The structure was renovated in the early 1980s and has undergone upgrades and minor repairs. The museum said that the overall goal of the construction in December is to “preserve the integrity of the building.”

When the museum opens in the spring, there will also be a new visitor center, a new classroom on the ground floor and new exhibitions. The museum will celebrate its 40th anniversary in 2020.