During the summer of 2020, Portland District took on a very important project. It put a new roof – one of the most vital parts of a building in the rainy northwest – on the Bonneville Project Office and Auditorium buildings, which are two of the U.S. Army Corps of Engineers’ most important historic resources.
In 1987, the U.S. Army Corps of Engineers and the National Park Service designated Bonneville Lock and Dam, which includes the civic auditorium and administration buildings, as a National Historic Landmark, or NHL. According to the National Park Service, an NHL is a property that is exceptionally significant for our nation’s history and heritage. Today, there are about 2,600 NHLs across the nation, but only 17 in Oregon and 24 in Washington. Nationally, the Corps owns only 13 NHLs, making Bonneville a true gem. Bonneville employed over 3,000 people during the Great Depression, and was one of the largest New Deal projects, proving that the federal government could stimulate the economy. It would forever alter the Columbia River and illustrated the nation’s commitment to developing the Pacific Northwest. Bonneville is also a remarkable feat of engineering. Corps engineers built the dam to “float” on a landslide, and they had to specially construct the turbines to handle the mighty Columbia River.
While constructing the cofferdams and pouring concrete for the powerhouse, the Corps also built a community for housing operators and their families. Notable Oregon architect Hollis Johnston designed 20 colonial revival-style homes in late 1934 to house employees.
Johnston also designed the civic auditorium and administration (today’s project office) buildings, which the Corps completed in May 1935. These buildings offered space for community events including Sunday church services, movies, sporting events, and even a hobby show where many of the men who built Bonneville showed off their “fine needle and thread work,” braided belts, signet rings, and model airplanes, according to the Mar. 28, 1935 edition of The Bonneville Dam Chronicle. In addition, the structures housed the post office and library.
Even though the Corps removed the residential buildings in 1982, the civic auditorium and administration buildings remain as a tangible connection to the past, providing everyone knowledge, enjoyment, and a shared sense of place - 85 years later.
But all buildings, especially those that are historic and in a very rainy environment, need ongoing maintenance and care. To address water intrusion, Portland District started planning for the civic auditorium and administration buildings to get a new roof and gutter system. Because both buildings are part of the NHL, the District incorporated preservation-appropriate actions into planning and design to meet requirements under the National Historic Preservation Act. Some of the actions and preservation solutions included:
- Roofing: Since the original cedar shingle roof had already been replaced, the District selected modern roofing material that mimicked the original. Contractors completed installation in a manner that respected the historic design.
- Gutters: Both buildings have an internal gutter system that represents 1930s workmanship. Contractors removed rotting trim and gutters but took care to reconstruct them using the same design and materials.
- Masonry: Contractors repaired masonry, specifically mortar, where it was failing and no longer able to withstand the new roof and gutters. Making sure new mortar matches the historic components is important on historic buildings. The District required the contractor to complete a mortar analysis and do mock-ups to inform decisions about the appropriate mortar mixology and color.
- Cupolas: After 85 years of wind and rain, the original wood cupolas were losing some of their stability. After considering the weight, water resistance and fire safety, the District decided to reconstruct the cupolas using sheet metal instead of wood. While losing historic materials is never ideal, District staff took great care to ensure the new cupolas matched the existing in design, dimensions and color. However, the cupolas did not lose all original material. With the assistance of metal fabricators, contractors cleaned, repaired and reinstalled the original, decorative orb on the Auditorium building.
Portland District worked with partners at the National Park Service and State Historic Preservation Office to make sure all project actions met Portland District’s needs, but also incorporated preservation best-practices whenever feasible.
People will remember 2020 for many things; and at Bonneville, it will be the year that two of the Corps’ most significant historic buildings got some much-deserved tender-loving-care.