St. Paul, Minnesota
Original construction of the Capitol began in 1896. Alexander Ramsey laid the first cornerstone in 1898, the dome was completed in 1902, and the building opened in 1905. The 500,000 SF building was designed by Cass Gilbert who also designed the US Supreme Court Building in Washington DC. It was modeled after Saint Peter’s Basilica in Rome and is crowned by the world’s largest unsupported marble dome, measuring 89 feet in diameter. The Capitol was built at a cost of $4.5 million.

Above the southern entrance to the building is a gilded Quadriga called “The Progress of the State”. It was completed and raised to the roof of the capitol in 1906. Daniel Chester French – sculptor of the Lincoln Memorial – designed the Quadriga. The Quadriga figures are made of copper and covered with 23-½ karat gold leaf. As part of an extensive restoration project, the Quadriga was removed from the capitol in 1994, restored and returned in 1995.
In 1972, the Minnesota Capitol Building was placed on the National Register of Historic Places. Over the years, water leaks have caused deterioration and the Capitol is currently in the process of being restored, interior and exterior.
Roof Spec Inc. has consulted on roofing in the area of the Dome and Quadriga. RSI has also provided consulting for the waterproofing on tunnels and plazas connected with the Capitol.