 Concerns over falling plaster ultimately prompted officials to close the rotunda to the public in the early 1980s.It remained closed until the building was renovated in the early 1990s for its new use as a federal courthouse.At that time, 40,000 pounds of new copper were brought in to re-cover the dome; holes in its plaster interior, as large as eight feet square in size, were painstakingly repaired, and the skylight was reopened.