The last major restoration was back in 1959-1960 and though the dome looks as it should from a distance, viewing the masterpiece up close reveals a different story. There have been over 1,200 cracks and breaks spotted on the exterior skin and the protective coating is delaminating which is allowing water to penetrate through to the cast iron and into the Rotunda itself. As the dome acts as an umbrella to what’s underneath, the Rotunda, it’s imperative that it retains it’s weather resistant capabilities. The damage to the dome has become so extensive that it’s no longer simply a matter of maintaining aesthetics, it’s become a mission of safeguarding national treasures and protecting the public. Over 100 pieces have been removed already as they posed a threat to those below.
To understand the problem confronting the restorers, one has to understand the construction of the Capitol dome itself. Designed by Thomas U. Walter and built between 1855-1866, it was not made from stone or concrete but rather cast iron, 8,909,200 pounds of it to be exact, all bolted together like a giant jigsaw. The design provided for two domes made from sheet metal with one sitting on the other, like stacked egg cups. Occupying the space between is an extensive latticework of iron beams that tie the two together. The dome was made from the material of preference at the time, though today a different material would undoubtedly be chosen. Past decisions aside, the U.S. Capitol dome is in need of some TLC.
Due to the nature of the material, the two year $60 million restoration will be a challenge for the restoration team. As the cast iron is too soft for welding and too fragile to accept regular bolts a team from California has devised a system to sow the cracks closed where possible, and where not possible sections will be replaced. The exterior metal sheets will be stripped of lead based paint to bare metal, then primed and repainted.
To carry out the work an extensive scaffolding system will be erected. It will envelop the dome for a good part of the restoration and allow workers access to every part of the structure. The majority of work will be carried out at night and on weekends. From the inside a circular donut shaped safety blanket will protect visitors to the Rotunda below and still allow them to admire The Apotheosis of Washington, the painting of George Washington that adorns the underside of the dome.
Many visitors will find the scaffolding intrusive to the Capitol experience, but the evidence doesn’t lie and the U.S. Capitol dome is in need of some TLC. The process will take some time but at least the decision to restore the dome to her former glory will ensure future generations the opportunity to take in one of the nation’s greatest architectural monuments.
By Scott Wilson