BANGOR — Stephen and Tabitha King have agreed to pay $3 million to overhaul their 100-year-old hometown library as long as another $6 million is raised from other sources.

Tabitha King serves on the building committee of the Bangor Public Library, which is planning a $9 million modernization. She’s also a former long-term board member.

One of the library’s most pressing needs is a new roof to protect its collection, described as the biggest in northern New England. The library’s current copper roof was installed in 1912 when the library was built, and library officials say it’s beyond repair.

The Bangor Daily News, which first reported the Kings’ matching grant, says Bangor residents will vote in June whether to take out a $3 million bond for the roof repair.