BAR HARBOR — The major renovation of The Turrets—a summer “cottage” built in 1895 and repurposed in the 1970s as the centerpiece of College of the Atlantic—is nearly complete.

The renovation of the massive granite structure came not a moment too soon.

“It was getting to the point that it was dangerous—slate falling from the roof, turrets separating from the main structure,” said Millard Dority, COA’s director of campus planning, building and public safety.

The $3.9 million project, which began in April 2013, preserved the outer envelope for the next century. The work included replacement of the roofing framing, a new slate roof, copper drainage and roof flashing; re-mortaring much of the exterior, reconstructing two oceanside turrets and seven granite chimneys, and replacing 99 windows and more than 20 doors, using energy-saving and historically accurate materials.

According to the website Daytonian in Manhattan, which chronicles “the stories behind the buildings, statues and other points of interest that make Manhattan fascinating,” The Turrets was one of two mansions commissioned by a major Cincinnati developer, John J. Emery.

“In 1892, John, aged 54, married the 18-year-old Lela Alexander, the daughter of U.S. Army surgeon, Charles T. Alexander, who would achieve the rank of brigadier general. The new Mrs. Emery had been born in a U.S. Army fort in the Indian territories,” Daytonian says. “Theirs was a socially prominent wedding and the Emerys would produce three daughters and two sons. John and Lela Emery would enter East Coast society by constructing two mansions—a Manhattan residence and the socially-required summer cottage.”

Emery hired prominent New York architect Bruce Price, renowned for his designs of Romanesque institutional buildings, Beaux-Arts mansions and skyscrapers. The stone was quarried locally and transported by draft horse. (Price designed three other private cottages and a hotel annex in Bar Harbor, but those are now gone.)

According to COA, the Emerys summered there for 11 years before his death in 1908. His wife remarried and summered there until her death in 1953. Her children retained the estate until 1958, when it was purchased by a local businessman who opened the house briefly as a tourist home. The property then was purchased by the Franco-American Oblate Fathers in1967.

COA purchased the mansion, by then in terrible disrepair, in 1973. In 1975, the building was placed on the National Register of Historic Places. Roc Caivano, a Bar Harbor architect, has said the mansion is “a significant example of American Residential Architecture.”

The Turrets became COA’s central administrative and classroom building, the structure kept in good health by restoration efforts in the 1970s and 1980s.

Still, said Dority, “We almost never renovated the building as it should have been in the first place. We’ve known for a long time it needed lot of work.”

A small liberal arts college of 362 undergraduate and eight graduate students, including 55 international students, COA offers a “human ecology” curriculum that encourages student-driven investigation of relationships between people and nature. In keeping with the college’s philosophy of hands-on education, about half a dozen students (and some alumni) were involved in the renovation plans and execution from day one.

A campus plan drawn up in 2001 identified architectural and structural issues. In 2013, a structural investigation and energy audit allowed planners to update the findings.

Construction began in April order to avoid interrupting the academic calendar as much as possible. Dority credits construction manager E.L. Shea, roofers Hahnel Brothers and masons Joseph Gnazzo and Co. for their excellent work.

The building now looks refreshed. Exterior landscaping and painting will be done in the spring.

“The Turrets is the anchor of this institution,” said Dority, who has been with COA for 41 years. “There are some who argue Turrets was built in an era when sustainability was almost antithetical. There were issues with that building, for sure. But it’s a very important part of the college. And Turrets was an important part of the development of the town. We examined every option, from razing, to only using it for summer programs, to complete renovation. I think we made a good decision.”