Freshly restored Brown County Courthouse dome takes a turn, baffling officials

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When Brown County officials unveiled the gleaming, copper dome of the county’s newly restored courthouse in November, it was a glimpse of what the building looked like when it was first built 107 years ago.

But residents watched in horror as the bright sheen of the copper dome quickly wore off just months after the restoration project wrapped. Now, the dome is once again a splotchy mess of tarnished metal.

Paul Fontecchio, Brown County’s director of public works, said it was frustrating to watch the glimmering dome dwindle. Although restoring the copper was a small part of the $1.7 million restoration project — which repaired leaks and replaced clock faces, among other work — the dimming dome has become a visible disappointment.

“That’s the part that has grabbed everybody’s eye of course,” he said. “When it was done it was very bright and very shiny and then all of a sudden it wasn’t.”

Brown County officials sent samples of the copper to a lab to determine what caused the copper to fade so quickly. But it could be months before the county has an answer, Fontecchio said. One possible culprit is a layer of linseed oil that Chicago-based consultants Simpson, Gumpertz & Heger recommended applying to prevent discoloration.

That $30,000 treatment was supposed to keep the dome free of blemishes for seven or more years.

It’s unclear if the treatment was applied improperly during the renovation, if the oil itself was inadequate to preserve the century-old metal or another environmental factor — wind-blown dust from coal piles nearby, maybe — could be to blame.

Fonteccio said county officials, who are not metal experts, relied on the advice of consultants, who have lead similar projects successfully in other places. According to the firm’s website, Simpson, Gumpertz & Heger mapped out repairs to the Massachusetts statehouse in Boston, built in 1798, among other historic projects.

Officials with Simpson, Gumpertz & Heger met recently with county officials, setting up stations to test the dome. Crews will try a variety of cleaners to see if they remove the dome’s discoloration and will monitor the dome’s condition for at least six months, the Green Bay Press-Gazette reported. Matt Johnson, a principal with the firm who worked with Brown County, did not immediately return a message seeking comment.

“We just relied on our experts,” Fonteccio said. He doubts that workers from Structural Group, who preformed the renovation, had much to do with the discolored dome. “It appears to us that the sealant was applied property. It’s not like it’s real complicated.”

The Brown County Courthouse was built in 1908 and was listed on the National Register of Historic Places in 1976. The interior of the building got a $10 million upgrade in 1992, and a lantern on top of the dome was replaced about a decade ago.

As testing continues to determine what happened to the dome, county officials are anxious to learn what caused the discoloration, and what could be done different, said John Van Dyck, a Brown County supervisor. Some have even floated the idea of abandoning a shiny dome altogether once officials learn what caused it.

“To be honest with you, we’re just grasping at straws,” Van Dyck said. “There were multiple things thrown out (for why the dome is dim), now any one of those suggestions could be viable. There’s an ongoing cost to keep it that way when you’re dealing with copper to keep its shine. Obviously that expectation may not have been a realistic expectation.”