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Oklahoma State Capitol Exterior Rehabilitation

Oklahoma State Capitol

Rehabilitation of 1917 Capitol Exterior

In 2015, the State of Oklahoma commenced an extensive exterior rehabilitation of the Oklahoma State Capitol—the first ever comprehensive rehabilitation to the historic building.

The capitol, completed without the dome in 1917, is constructed primarily of Bedford limestone, more commonly known as Indiana limestone, and two types of granite native to Oklahoma:  a pink known as Tishomingo quarried near Troy and a black or gray from Cold Spring.

The primary goal of the project is to halt deterioration and correct damage on the 98-year-old exterior that affect visitor and occupant safety and building envelope performance including:

  • Repairing and cleaning granite and limestone
  • Repairing historic windows
  • Repairing and repainting cast iron window frames and oramental spandrel panels
  • Repairing and refinishing exterior doors including security and accessibility upgrades
  • Assessing the copper roofing to determine necessary repairs.
  • Restoring decorative items such as limestone griffins and column capitols


As the design architect and historic preservation specialist, Treanor Architects is responsible for directing field investigations to confirm existing conditions and develop design solutions for typical and special exterior masonry, cast iron and copper repairs. Treanor is working with ADG, the project’s architect of record, and JE Dunn Construction, the contractor and design-build team leader, to complete this rehabilitation.