Martin County Courthouse Dome and Roof Restoration

Fairmont, Minnesota


Architect and Engineer

Mankato, Minnesota

Sheet Metal Contractor

Renaissance Historic Exteriors
Rockford, Illinois


Mechanical Watch Supply, LLC
Minneapolis, Minnesota

Designed in a Beaux Arts style by architect Charles Bell, Martin County Courthouse is a three-story stone building, with a fifty-foot copper dome cap featuring four clocks, each seven feet in height. Four copper eagle statues are perched around the dome overlooking the City of Fairmont and beautiful Lake Sisseton in southern Minnesota. After over a century of service, the courthouse needed restoration.

Built in 1907 and listed on the National Register of Historic Places, it had suffered water infiltration in multiple locations that damaged historic artwork and jeopardized its structural integrity. To address these issues, local officials engaged engineers from ISG and fabricators from Renaissance Historic Exteriors to repair the courthouse’s many copper elements, including the dome and clock tower, eagle statues and finials, and roof system.

For the roof, the team constructed a new standing-seam system using 20-ounce copper. They fabricated sections offsite at the Renaissance workshop, which they then brought to the site for installation. When assembling the dome, the team faced a number of challenges. Copper ribs toward the base of the dome had different radii than those at the top, and each section required soldering on the back side of the rib and additional soldering on the front where sections meet. Similarly, the roof panels had different radii and widths, requiring significant care to solder together.

Many of the other copper elements required even more demanding skill. For example, replicating the four eagle statues required the team to join components created with 50 different molds together. Just as challenging was creating the custom copper facing for the large clocks. Installers first had to address the crumbling cinder concrete substrate, to which the original copper roofing had been attached without furring or sheathing between. The Martin County Courthouse restoration project succeeded in duplicating old-world craftsmanship using modern techniques that will allow the century-old copper dome, clocks, and eagles to serve as beacons of justice for future generations. 

Photo Credit: ISG

Photo Credit: ISG

Photo Credit: ISG

Photo Credit: ISG

Photo Credit: ISG