Wednesday evening update:
The National Trust's presentation did not bring the Milwaukee County Task Force on the Mitchell Park Conservatory Domes any closer to its mission. It is "to recommend a course of action to the County Executive and County Board" on a sustainable future of the Domes.
Milwaukee County Parks Director John Dargle described the National Trust's report as "weak and vague."
Fellow task force member John Gurda suggested Milwaukee County engineers analyze the report and provide feedback at the next meeting. Its date has not yet been set.
Original Story from March 22 at 10 a.m.:
The future of the Mitchell Park Horticultural Conservancy, known by many as The Domes, has been thrown into doubt in recent years when structural concerns forced their temporary closure.
Milwaukee County operates the Domes and has explored several possibilities regarding what to do with them, including demolition of one or more of the three structures. The county hired the firm GRAEF to study what it would take to save the buildings.
The National Trust for Historic Preservation has also gotten involved. First in 2016, the National Trust added the Domes to its list of America’s 11 Most Endangered Historic Places.
“It’s primarily a tool to focus public attention on important threatened historic places, so it really sort sort of just shines a light on those places nationally,” the National Trust's Jennifer Sandy says.
According to Sandy, the Domes are important because of their unique construction. "They're very iconic silhouettes. They’re a significant examples of mid-century modern American architecture and engineering, so there’s a lot of reasons we think they are nationally important and should be better known,” she says.
The Domes design resulted from a national competition. Milwaukee architect Donald L. Grieb won, and construction stretched from 1959 to 1967.
“They are the world’s first glass conoidal domes,” Sandy says. “They are still the only glass conoidal domes used as conservatories.”
To build the case that the Domes should be rehabilitated, the National Trust brought in an engineering firm to take a look. Sandy says Wiss, Janney, Elstner Associates, or WJE, has worked on St. Louis’s Gateway Arch, the Metropolitan Museum of Art in New York and the Washington Monument.
Milwaukee County has contracted with a local firm GRAEF since 1993 to provide architectural and engineering consulting services.
The WJE team reviewed five restoration options laid out by GRAEF.
“They are finding that water infiltration into the Domes is really at the root of many of the issues that are being experienced there,” Sandy says. “They (WJE) have suggested an approach that is slightly different than that suggested by GRAEF.”
She says WJE is suggesting a redesign of the Domes pressure caps. “The pressure cap is the element where the glass is meeting the connector to the concrete structural element. That’s the location where there has been water leakage is. Essentially redesigning the pressure cap will solve the water leakage problem."
Sandy calls WJE’s an enhanced approach, which the firm estimates will cost approximately $18.6 million. “That’s around one-third the cost of the full rehab option developed by GRAEF."
She hopes WJE’s input and the National Trust’s enthusiasm to help protect the Domes for future generations will help.
“We know the County and the task force are considering a range of options and have been working with GRAEF and others to look at conservatories in different communities that could be models.” Sandy adds, “It’s great to see discussion that’s comprehensive about the future of the facility and we just think this is an important piece to add to the conversation, so we know what all the potential options are for rehabilitation approach and cost estimates.”