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There have been 43 U.S. presidents, but only 11 have libraries dedicated to the preservation of their documents and related history. Those 11 include Herbert Hoover, the 31 st president.
Hoover, who served from 1929-1933, forever will be associated with the Great Depression. But history now remembers him as “The Great Humanitarian.” That history is documented in the Herbert Hoover Presidential Library and Museum in West Branch, Iowa, not far from Iowa City. The library opened to the public in 1962, and was several times expanded – most recently in 1992 – to become the sprawling 44,500-square-foot complex it is today.
But degrading roof systems threatened the invaluable library and museum collections. To help preserve these U.S. treasures, F.J.A. Christiansen Roofing was selected to replace the roofs under a rigorous series of federal building and historic preservation guidelines.
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“There were strict criteria for this project,” said Charlie Schulz, F.J.A. Christiansen's project manager for the job. “A number of potential contractors opted out of the bidding because of the extensive project criteria.
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F.J.A. Christiansen has significant experience in historic preservation work, including the roof replacement work at the Federal Courthouse in downtown Milwaukee, Milwaukee County Courthouse, Basilica of St. Josaphat in Milwaukee, Holy Hill National Shrine of Mary in Washington County, and the current copper replacement for the Milwaukee City Hall south tower.
“The government specifications called for high-quality materials, high levels of insulation and reproduction of existing but deteriorated sloped slate and flat roof elements, including fiberglass reinforced plastic copings and wall panels,” said Operations Manager Greg Johnson.
On top of those requirements, the roofing crews had to ensure their work in no way threatened the seven million pages of historic documents in the library, and did not disturb the researchers, historians, tourists and school children who regularly visit the facilities.
“We were working over a collection of priceless, irreplaceable documents,” Johnson said. “While we don't want work-related water leaks on any job, we were extra careful on this project.” As much as possible, new roofing was installed the same day as sections of the old roof were removed.
The building itself is controlled by the U.S. National Archives and Records Administration, but the land – the Herbert Hoover National Historic Site – is controlled by the National Park Service, with each agency having its own set of regulations that contractors must adhere to.
“We had to have minimal impact on the grounds,” Schulz said. “The work areas had to be fenced off, yet we could not obstruct the view from President Hoover's birthplace cottage to his gravesite, which are on opposite ends of the grounds.” Johnson added that, “The work areas were limited, and most access to the roof area had to be from the rear of the building.”
The Homeland Security Act also came into play, requiring background checks on workers and shutting down work during elevated terrorism alerts.
The grounds can be quite busy, particularly in August for Hooverfest but also for a number of other events and numerous school field trips. The library attracts quite a few researchers who have access not only to Hoover's documents and those of his presidency but, also, to a varied collection of Hoover-era records, especially those relating to conservative politics at the time. More than 2.5 million people have toured the museum since it opened. “We had to make an extra effort to control noise and fumes that might disturb the researchers and visitors,” Johnson said.
The work itself consisted of multiple low (flat) and steep sloped roof systems at different elevations, including 17,000 square feet of a slate roof system and 20,000 square feet of low slope roof area. The slate system covers a mansard-roofed section of the museum.
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All existing materials on the flat roof were removed down to the gypsum or metal decking. The new system started with half-inch-thick DensDeck gypsum boards in the metal areas, with polyisocyanurate and extruded insulation placed over that underlayment, all set in a low-rise foam adhesive. This type of adhesive is a relatively new product utilized in lieu of more traditional mastics such as hot asphalt. This application allowed us to conserve space on an already crowded work site – space that otherwise would have required set up for an asphalt tanker or kettle. The foam works similar to an epoxy in that there are A and B components that are mixed together in a specialized applicator that resembles a caulk gun. Quarter-inch DensDeck Prime was also laid in foam adhesive, with an 80-mil, fully adhered Sarnafil PVC membrane.
Sarnafil G410 80-mil membrane was then selected as the roofing and flashing membrane. Sarnafil has a worldwide reputation for durability and sheet integrity and the 80-mil sheet is its thickest sheet. Previously available as either reinforced or nonreinforced, today's PVC membranes are reinforced with either glass fiber or polyester. This Sarnafil membrane is fiberglass reinforced for dimensional stability. In addition to an obvious difference in physical properties between PVC and EPDM (rubber) membranes, another significant difference is that the seams of a PVC membrane are physically heat-welded together as compared to EPDM seams which are brought together through the use of adhesive tapes. A custom gray color was used rather than the usual white to soften the visual impact of the roof from neighboring buildings that look down on the Hoover Library from the hilltop above.
Because of the length of the slope in some areas, the resulting roof assembly in those locations is R55 or greater, due to the depth required to attain that slope.
The flat roof area had fiberglass reinforced plastic wall panels and coping that had to be removed and replaced to maintain the existing look of the building, presenting some challenges. “They didn't want to change the overall look of the building, so we had to prefabricate some new prefinished galvanized steel copings in a color that closely resembled the existing copings,” Schulz said.
Crews had to deal with an unusually large number of unexpected structural issues, most related to additions, which were uncovered when the existing roof systems were removed, Johnson said. “There were several additions to the original structure, but those additions were not always well documented,” he said. “In some cases, the information we had on existing roofing was just speculation. We did some sampling, but even that did not reveal everything.” For example, he said some areas that were thought to have gypsum plank decking actually had metal decking, and visa versa. |
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Communications on the project required extra coordination. “With the project in Iowa, us in Milwaukee, the architect in Detroit and the government in Washington, we had to make sure communications were not hindered,” Johnson said. Formal monthly meetings were conducted on site, as well as more frequent informal meetings and plenty of e-mail and telephone communications.
“The entire project was very challenging with many different constraints, but it was a great privilege and honor for us to work on a project like this,” Schulz said. “There is a tremendous amount of irreplaceable historic documents in the library and museum; we're pleased that F.J.A. Christiansen was chosen to help protect that history.”
Key F.J.A. Christiansen personnel on the Hoover Library and Museum project in addition to Schulz and Johnson were safety director Rich Trewyn, sheet metal superintendent Jeff Keller, roofing crew manager Pete Shick, and sheet metal foreman Ron Powell.
(Information on the Herbert Hoover Library and Museum can be found at http://hoover.archives.gov/ . The Hoover Library is the closest presidential library to the Milwaukee area, followed only by the Gerald Ford Library in Ann Arbor, Mich. The Gerald Ford Museum is the closest museum to Milwaukee, in Grand Rapids, Mich. Information on the Ford museum and library can be found at http://www.fordlibrarymuseum.gov/default.asp.)
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