Credit: Hoffman Architects

Buildings can have a shelf life measured in centuries—if they’re maintained properly. Starting this November, the iconic U.S. Capitol Dome will undergo a two-year restoration to address significant deterioration and water infiltration issues. The Architect of the Capitol (AOC), Stephen T. Ayers, FAIA, will oversee the restoration, with Hoffmann Architects serving as the architect-of-record, which has been developing a master plan for restoration with the AOC since 1990. A joint venture formed between Turner Construction Company and Smoot Construction will perform the construction work.

Designed by Philadelphia architect Thomas Walter, the 8.9-million-pound, cast-iron dome was built between 1855 and 1866 for just over a million dollars, according to the AOC’s website. Its last restoration occurred in 1959 and 1960, and comprised exterior repainting, repair and replacement of flashing and connections, and structural reinforcing of the Statue of Freedom.

Weather and age have taken their toll over the last century and a half. Though the 96-foot-diameter dome may look pristine to visitors standing nearly 300 feet below, its deficiencies include nearly 1,300 cracks in its exterior, material deterioration, delaminated paint, and loose finials and architectural features.

The $59.6 million project will take two years to complete. Like its equally-iconic landmark down the National Mall, the Washington Monument, the Capitol Dome will be covered with scaffolding throughout the project duration. Scaffolding will begin from the base of the Statue of Freedom down to the top of the Dome skirt, with additional scaffolding systems constructed on the west side of the U.S. Capitol Building for material transportation, according to the AOC. Inside the Capitol Rotunda, workers will install a white, doughnut-shaped, canopy-netting system that will allow the Apotheosis of Washington, in the eye of the Rotunda, to remain visible throughout the renovation. The Rotunda will also have a covered walkway. Most of the work will be conducted at night and on weekends.

The AIA commended the project’s kick-off in an Oct. 22 press release. “Investments made now in government buildings and infrastructure pay off in reduced costs and efficiency years from now,” said AIA president Mickey Jacob, FAIA. “We hope that the announcement of a much-needed restoration of the U.S. Capitol Dome signals a renewed emphasis on this principle.”