Plans for a new gymnasium at Buffalo Academy of the Sacred Heart, a sore point for neighbors who live behind the project site, will move ahead after a key approval Tuesday night by Amherst leaders.

The $3 million project was green-lighted by the town’s Historic Preservation Commission, whose members said a garage that needs to be demolished for the new gym to be built was not historic.

“We’re really pleased,” said Jennifer Demert, head of school at Sacred Heart. “It’s been a long time coming.”

She was referring to a contentious back-and-forth with residents who live behind the academy and who said the proposed gym was not in keeping with the historic nature of the academy or the surrounding Eggertsville neighborhood.

A key break in the dispute came when Raymond Volpe, a neighbor who proposed a historic designation on the Sacred Heart property, withdrew the historic nomination Tuesday night.

Volpe said a marathon series of meetings last weekend with Sacred Heart lawyers and officials produced a change in the facade that he felt was in tune with neighborhood aesthetics.

“They were originally going to put up a tin barn,” Volpe said after the meeting. “The design now is in keeping with the rest of the campus and enhances the whole campus. We succeeded in getting what we were looking for.”

Volpe’s withdrawal of the nomination set the stage for the preservation commission to issue a demolition permit for crumbling garages, which members said were not historic and did not contribute to the architecture of the 1930s academy building.

“This is a recent construction, sometime in the last 50 years,” said commissioner Paul F. Redding. “Certainly it’s not a historic structure, based on my 45 years in historic properties.”

While Volpe was pleased with the result, some of his fellow neighbors said the compromise did not go far enough.

Sheree Lamendola, who lives behind the academy, said Volpe withdrew the historic designation application against her will.

She said she and other neighbors wanted assurances from an appraiser that their property values would not go down as a result of the gym construction.

“We want a third party to say it’s OK,” Lamendola said of the property values.

Aside from the gym, she said the larger concern is that Eggertsville – one of Amherst’s few historic neighborhoods – could become the next place developers seek to build large structures.

Those concerns are playing out as two controversial hotels on Main Street are being built, and as a large Eggertsville property, the former Cantalician Center, sits as a prime parcel for development.

“We’re afraid of a Mike’s Pond situation, to have something tower over us,” Lamendola said, referring to the proposed Hyatt hotel.

She acknowledged, though, that the gymnasium is likely to move ahead with the demolition permit and expected approval from the Planning Department.

Demert, of Sacred Heart, said the academy would continue to work with the neighbors but would begin construction as soon as the permit is issued.

“Our hope is to start the basketball season in our new gym this year,” she said. “We will continue to be good neighbors.”