What do the Bangor Public Library, Schenck High School and Darling’s Waterfront Pavilion concert venue have in common?

The solution to many of their problems lies overhead in the roofs that have covered the first two structures for decades and, in the latter case, the roof that doesn’t yet exist.

The Bangor Public Library needs a new roof to ensure its valuable collection is protected from the elements. Library staffers last fall set up scaffolding in a second-floor room to brace a collapsing ceiling. “Band-Aids won’t work anymore,” library director Barbara McDade told the BDN in March about the library’s original, century-old oxidized copper roof and dome.

In East Millinocket, school and town officials have wrangled over whether taxpayers should foot the bill for a new roof over the building that houses Schenck High School and Opal Myrick Elementary School. Replacing the leaky covering — along with repairing cracks in the gymnasium walls and remodeling bathrooms and a drinking fountain — would cost about $2 million, but that project could be only the first of many improvements needed to shore up the 1957 school.

In the end, the improved building could offer East Millinocket a better shot at keeping a school open in the shrinking community.

Back in Bangor, a roof atop the Waterfront Pavilion would provide the ultimate answer to an ongoing debate about noise from the Waterfront Concerts series that affects the quality of life among residents of Bangor’s East Side. The construction of the Waterfront Pavilion this year redirected noise away from Bangor’s West Side neighborhoods, which had been the source of noise complaints in previous years of the concert series. The problem is, the noise now booms eastward.

A roof would contain sound from the stage, likely keeping concert-goers and nearby residents happy, but it’s simply too expensive for the Waterfront Concerts series or the city of Bangor.

The similarities extend one step further for the Bangor Public Library and Schenck High School. They have both had angel investors with deep pockets step in to save the day.

In March, two of Bangor’s most famous residents, Stephen and Tabitha King, said they would contribute $3 million toward the Bangor Public Library’s $9 million renovation; the roof accounts for a third of the cost. The condition? The library would have to raise the remaining $6 million. Bangor voters approved a $3 million bond for the roof in June, the library raised $1.7 million during the quiet phase of a capital campaign, and it has about $1.3 million left to raise.

And just last week, former East Millinocket resident Gloria MacKenzie, who now lives in Florida, pledged $2 million from her recent $278 million Powerball jackpot winnings to repair Schenck High School’s roof. MacKenzie’s condition? East Millinocket voters would have to approve their school system budget, which they rejected in late June.

The fact that angel investors have swooped down to prop up two structures in desperate need of new roofs means there could soon be a lot of repair work happening over our heads in Bangor and East Millinocket.

In the third situation, city councilors and concert organizers in Bangor are still left with a noise debacle involving unhappy residents and concert-goers who would be unhappy if the performances they attended were shut down or quieted down.

An angel investor willing to put up the funds for a new pavilion roof could easily solve the problem at hand. But the city and Waterfront Concerts would be unwise to stake their hopes on a wealthy benefactor coming forward.

Which leaves councilors, concert organizers and residents with a challenge: Arrive at a fair solution that’s likely to involve compromise.