JE Dunn led the renovation, repair, and restoration of the exterior of the Oklahoma State Capitol, which was originally built in 1917. Working closely with the design team to evaluate and design, the scope of work included repointing of mortar joints, a painstaking and time-consuming process to protect the building from water infiltration; repair of cracked and damaged stone using the Dutchman Repair process; stone cleaning using a micro-abrasive process; scaffolding to allow the stone masons to gain access to all areas of the building’s exterior; restoring all 477 windows that surround the building and replacing all four wings of the existing copper roofing.
After a century of heavy use, harsh weather and inconsistent maintenance and preservation efforts, the building’s mechanical systems were failing, the exterior façade was crumbling and its prospects of meeting the state’s needs for another hundred years were fading. Recognizing the need to act, the Legislature enacted legislation providing funding for the Capitol’s first-ever comprehensive, top-to-bottom restoration.
There were over 21 miles of mortar joints on the Oklahoma Capitol. Due to the poor condition of the existing mortar, every single joint on the building had to be ground out and new mortar installed. It was a painstaking and time-consuming process in order to protect the building from water infiltration. JE Dunn tested various mortar types on the building to determine how well they weather Oklahoma’s climate and relate to the limestone, in order to deliver the best solution.
There were 240 locations on the Capitol where stone spalled and had to be repaired. Using the Dutchman Repair process, the damaged area was cut out and replaced with a new piece of stone. Stainless steel anchors were also installed. The repairs are barely visible to the naked eye and unnoticeable at higher elevations. The project was a 2020 AGC Build Oklahoma Award Recipient.