After scoring early victories in its battle to build a new gym on its Covington campus, St. Scholastica Academy has suffered a second defeat that could help land the project in limbo.

The latest setback comes from the city’s Board of Adjustment, which voted 3-2 Monday to send the gym proposal back to the city’s Historic District Commission for reconsideration after the project’s designers made significant changes to the plan the commission approved in April.

St. Scholastica, a 111-year-old Covington girls school that is run by the Archdiocese of New Orleans, has been trying for months to get approval to tear down the current gym and a nearby building to make way for a larger gym and multipurpose center.

The school’s case for the project rests on a simple premise: The old gym is too small for the school’s 650 students.

Opponents, however, say the proposed 56,000-square-foot gym and multipurpose building would dwarf surrounding houses, create traffic problems and overwhelm the neighborhood’s historic feeling. They have questioned the need for such a large building and complained there was not enough community involvement in formulating the plan.

Key to the Board of Adjustment ruling Monday was whether the changes that have been made to the plan since it was approved earlier were substantive enough to order it back to the Historic District Commission. The agenda referenced two specific changes: a reduction in total square footage of about 9,000 square feet and a change in the setbacks along two of the streets that would border the gym.

The Board of Adjustment’s vote to send the revised plan back to the historic panel delighted the project’s opponents.

Annie Spell, a 1983 graduate of the school, said the board made the right decision. Doing otherwise would have set a precedent that could have allowed future developers to alter the size of their proposals without having to get a new approval from the Historic District Commission, she said.

“The decision affects whether or not any other giant metal box gets built next to a house,” Spell said. “What the CHDC did was approve one thing, and we don’t want another large-scale developer to make changes.”

Spell, who lives four blocks from her alma mater, also chided school officials for not having engaged the community enough.

“They have made no effort whatsoever,” she said.

Archdiocese of New Orleans spokeswoman Sarah McDonald said church and school leaders will meet soon to determine their best course of action going forward.

The Board of Adjustment was the fourth public body to consider the project this year. The Historic District Commission voted 5-0 in April to award the project a “certificate of appropriateness.” Opponents of the project appealed that decision to the City Council, which upheld it by a narrow, chaotic, 4-3 vote.

But the project ran into difficulty this fall when it went before the city’s Planning and Zoning Commission, which voted to table it indefinitely after City Attorney Rod Rodrigue said unresolved issues had to be resolved by other bodies, including the Board of Adjustment. Now, with that board’s decision Monday night, the project’s future remains unclear.

St. Scholastica attorney Paul Mayronne, who angrily addressed the Zoning Commission after it tabled the issue, sounded more resigned Tuesday.

“It’s certainly going to continue to delay moving the project forward,” he said. “It is frustrating. The continuing delays are very frustrating.”

Follow Faimon A. Roberts III on Twitter, @faimon.