North Dakota State Capitol Window Restoration & Replacement
One of the country’s most unique capitol buildings
At 21 stories, the North Dakota State Capitol is one of only three capitols in the United States with a high-rise tower. A fire in 1930 burned the original 1884 capitol building, and in its place rose the current skyscraper, which was built in a restrained Art Deco style and finished in 1934.
Designed by Holabird & Root, the capitol building’s unique design consists of a three-story Great Hall entry with a two-story legislative wing for the House and Senate chambers and on the opposite side of the Great Hall, a high-rise tower for North Dakota’s executive branch and for all state agency offices. This design was chosen due to limited funding available during the Great Depression and the high-rise tower design was “one of the most efficiently built government buildings in the country with a floor plan providing 80 percent usable square footage.”
While modern compared to many other statehouses, the North Dakota State Capitol began showing signs of its age. In particular, the building’s windows were aging and not performing as they used to. When the Treanor Historic Preservation team began working with the State of North Dakota, the last major update to the facility’s windows had taken place more than four decades ago.
Research and assessment: a critical process for rehabilitation
To understand the project, historic research was required. Original construction documents showed that the windows in the Great Hall were bronze, while the windows in the tower and legislative wing were to be aluminum windows. However, original photographs and historic documentation show that aluminum windows were not used, and wood double-hung windows were selected as a cost-savings measure. After 40 years of high exposure, these windows were replaced in 1974 with aluminum windows. Over the past 50+ years, window technology has advanced greatly, offering improved insulation, stronger materials that reduce heat transfer, and designs that more accurately replicate historic window styles.
Treanor’s Historic Preservation team traveled to North Dakota to inspect the existing conditions in-person. Over three days, we covered 21 stories and assessed 818 windows throughout the complex. We documented the details and completed condition assessments to determine the level of deterioration and if any significant differences existed that could impact the replacements.
Some damage and deterioration were obvious because winter snow and summer pests were making their way into the building, while other conditions were less obvious and required a trained eye to identify issues. After determining the windows’ condition and documenting historic elements, three alternative solutions were presented to the State.
Evaluating options
Working with the Facility Management Division, we not only assessed all 818 windows on the building and the intersecting building elements, but we also evaluated multiple window types and systems in order to determine the most cost-effective and energy-efficient windows that fit the State’s budget.
We developed replacement options to weigh the cost-benefit of each solution against its potential impact on historic character and improve energy efficiency.
The first solution would replace all windows with historic-profile aluminum double-hung windows to closely match what was originally constructed. The second option proposed using more ornate aluminum casement windows to replicate the original aluminum design intent, as shown in the original construction documents. The third proposed option used simplified/non-historic profile aluminum double-hung windows.
Working closely with the North Dakota State Historic Preservation Office, the decision, which considered historic preservation issues and budget, resulted in choosing the first aluminum window option. The aluminum windows will match the visual goals of preserving the original appearance while providing higher energy efficiency and lower annual maintenance.
In addition to the replacement of the existing non-historic double-hung windows, Treanor addressed the restoration of the historic aluminum storefront on the West facade of the building, and the 17th-floor historic aluminum doors.
The final scope of work included documentation and research of the historic Van Kannel revolving doors. The goal is to guide the restoration and repair to make these historic doors operable, functional, and weather-resistant for use during ceremonial events. Theophilus Van Kannel, who patented the “storm-door structure” in 1888 to improve energy efficiency, reduce street noise, and manage foot traffic, originally marketed them as “always closed” to eliminate drafts. Van Kannel received the John Scott Medal in 1889 for his invention and was inducted into the National Inventors Hall of Fame in 2007.
Preserving an occupied historic building while preparing for the future
Construction will have its challenges because of the limited time between North Dakota’s long winters and the beginning of the legislative session. The building is always occupied, requiring detailed logistics to allow business within the Capitol to continue during construction.
The “Skyscraper on the Prairie,” as the North Dakota State Capitol is affectionately known, is approaching its 100th anniversary. The window replacement project and storefront reglazing/door restoration will be a critical historic preservation initiative, making the building more sustainable, resilient, and comfortable for those in public service.
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