Completed during the Civil War, the U.S. Capitol dome is made from the high-tech material of its day—cast iron. Lighter and easier to work with than stone and more fireproof than wood, it had one major drawback; it rusts and cracks over time. The exterior was last restored in the early 1960s. Since that time the dome has deteriorated to the point where it is now undergoing its first complete restoration. Work began in late 2013 and is expected to be finished in time for the presidential inauguration in 2017.
One of the first technical challenges faced by restoration workers was how to get to the areas that need to be repaired. Their solution? Erect enclosed staging around the entire exterior of the dome (52 miles of scaffold pipe) and install a protective canopy inside to prevent debris from falling onto the millions of people who visit the building each year.
The Washington Post produced an excellent story on the project that includes a cool animation of the staging process. A different animation can be found in the first video below and an overview of the project in the video below that. Be sure to see the statistics for the project on the Architect of the Capitol’s website.