United States Capitol Dome
Washington D.C.

Original Architect
Thomas U. Walter with Montgomery C. Meigs (completed 1866)

Building owner
United States Legislature

In collaboration with
Office of the Architect of the Capitol

Building description
The current dome of the United States Capitol was designed by Philadelphia architect Thomas U. Walter between 1854 and 1859. Construction of the Dome began in 1856, with the removal of Charles Bulfinch's 1824 wooden dome, and was completed in 1866 when Constantino Brumidi finished his remarkable frescoes at the interior of the dome. Montgomery C. Meigs served as the superintendent of construction during most of that period.

Walter's design for the Dome of the United States Capitol employs the neo-classical vocabulary used in other portions of the building and throughout the capital city. It is also a style that the architect was a familiar proponent of, having previously designed numerous residential, commercial and institutional buildings in the styles of Greek and Roman revival architecture.

One of the innovations of the design of the Capitol Dome is the extensive use of cast iron for the structural and decorative elements of the dome. The cast iron for the dome of the Capitol was manufactured predominantly by Janes, Fowler, Kirtland and Company of New York. The projecting ornament includes column capitols, modillions, window hood finials, pendant ornament and consoles.

Scope of work

• Hands-on inspection of all projecting ornament at the exterior of the dome from the top of the lantern to the peristyle column capitals.
• Documentation of existing conditions of cast iron ornament.
• Temporary stabilization and waterproofing measures at selected areas of ornament.