BANGOR – School department officials on Monday will present to the city’s finance committee a plan to expand the crowded Bangor High School.

Robert “Sandy” Ervin, Bangor school superintendent, said this week that the plan, which carries a preliminary price tag of $4.5 million, is sorely needed to alleviate the space crunch in the 36-year-old building.

“If we don’t do something about this, what the public expects from this school is going to be hard to sustain,” Ervin told members of the Bangor Daily News editorial board Monday. “We’ll be able to do it, but we have to move on this.”

Ervin will present the plan at the City Council’s finance committee meeting at 5 p.m. Monday, Nov. 20.

Under the tentative plan, about 15 rooms and a small lecture hall would be added onto two wings of the existing building. The size of the school’s library would also be increased by 50 percent.

Currently being reviewed by faculty and administration, the proposal would extend the first floor of the high school’s A-wing to create space for four new classrooms and a foreign language laboratory.

The renovated A-wing would also include new, full-length lockers to replace about half of the school’s smaller lockers. The remaining lockers would be replaced within two years, Ervin said.

Under the plan, a suspended corridor would also provide an alternate route for students in order to alleviate congestion in the lower B-wing lobby, Ervin said.

The A-wing’s second floor also would be expanded to create about six new classrooms, he said.

Plans also call for a second floor on the science wing that would include four new laboratories and a 100-seat lecture hall. The science wing, which was designed for a second floor, was completed in 1988 at a cost of about $920,000.

Before new construction could start, however, the plan must first gain approval from the school committee and the city planning board as well as financial backing from the City Council.

City Manager Edward Barrett said the plan, based on its preliminary price tag, would add between 25 cents and 30 cents to the city’s tax rate of $24.35 per $1,000 in property valuation.

The estimates are based on repaying a bond at 5 percent interest over 20 years.

Ervin said about half of that cost could be made up in tuition payments from out of town students, more and more of whom are opting to go to Bangor High School, he said.

The school was originally designed for between 1,400 and 1,450 students, Ervin said. Bangor High currently has 1,447 students, 173 of whom are tuition students.

Although the school population is currently within the design specifications, the changing role of education requires more space for specialized programs, Ervin said.

With more rooms devoted to smaller special education classes and honors classes, classroom space has become scarce, according to school committee Chairwoman Martha Newman.

“You won’t solve this by hiring more people,” she said. “We have nowhere to put them.”

School officials have also cited the need to cut class sizes, some of which are “maxed out” at 30 or more students, Ervin said, as a reason for the expansion.

While final plans are still months away, school officials hope the addition can be ready by next fall.