It could cost up to $3.1 million to repair the historic Sandwich Opera House.

“It’s kind of sobering,” Sandwich City Administrator Geoff Penman said in addressing City Council members at their Jan. 2 City Council meeting. “There’s quite a bit of work that needs to be done.”

The $3.1 million repair estimate would include the installation of new copper gutters. The performing arts theater hosts shows throughout the year.

“Hopefully they can find a material that would be equal but hopefully less dollars,” Penman said. “This EPDM roof looks OK, like it might be salvageable for the time being. But the heating, ventilation and air conditioning units need to be looked at. The biggest issue is probably the roof drains and the gutters. It’s just unfortunate, but it’s stuff that needs to be updated.”

EPDM stands for ethylene propylene diene terpolymer, a rubber roofing membrane designed to be doable and long-lasting.

Built in 1878, the Sandwich Opera House is on the National Register of Historic Places. Penman noted the last time any extensive renovation work was done on the Sandwich Opera House was in the 1980s.

The Grecian-style Sandwich Opera House was built for $12,000 in 1878 by Enos Doan. The building was renovated in 1895 and again from 1984 to 1986 after years of neglect. It was placed on the National Register of Historic Places in 1979.

“It’s starting to come apart in spots,” Penman said. “Nothing lasts forever. “There’s rotting wood underneath the roof due to water infiltration. You go up into the attic and you can see daylight outside. So we’ve got some significant wok that has to happen to it.”

Belvidere-based Renaissance Historic Exteriors evaluated the building to see what repairs needed to be made. Penman said he might have someone from the company give a presentation to the City Council in the near future.

Renaissance has experience in the restoration of historic buildings.