The Town Council has unanimously approved $18.6 million to renovate and expand 58-year-old Saxe Middle School by fall 2017.

Jennifer Murphy, a Saxe parent, alluded to comments made by parents and administrators and the research by the project’s building committee that the school on South Avenue was already past its 1,200-student capacity, and any delay would detract from the district’s emphasis on quality instruction.

“Over the past year and certainly this fall the citizens have made it abundantly clear they want the Saxe project to happen,” Murphy said Monday night. “… Any further debate or opposition after tonight would be a waste of time and money. Clearly a broad spectrum of residents of this town want the project, and further opposition will fail.”

Plans for the project began to evolve when the auditorium was closed following he discovery of poly-chlorinated biphenyls in paint and other areas. In the midst of planning for remediation and an auditorium upgrade, the town-appointed Saxe Middle School Building Committee concluded there was a need for an expansion of the school to meet rising enrollment projections.

The project now includes a 16-classroom addition on the northwest side of the campus, resulting in a gain of 12 classrooms, and additional musical instruction and storage space adjacent to the auditorium.

Earlier this month, the New Canaan Board of Finance voted 8-0 to approve bonding for the project after a presentation by the town’s independent bond and investment consultant predicted the project would result in a peak cost of $189 a year for each taxpayer in 2017-2018 if the town borrows the $16.1 million it needs for the project over 20 years.

The state Department of Education is expected to provide about $2.4 million in reimbursement for the project.

At the beginning of the meeting, Michael Nowacki, a resident and founder of the New Canaan Taxpayers’ Alliance asked the group to delay the vote on issuing the bonds because the most up-to-date enrollment numbers for the schools show a 37-student drop in the total number of elementary school students in grades K-4.

The figures, presented to the Board of Education Nov. 9, the night before the Board of Finance vote, should have been disclosed to town officials making the decision on the project, Nowacki said. The presentation to the Board of Education also cited projections by the New England School Development Council showing K-4 school enrollment would increase from 1,594 to 1,628 next fall,with 34 additional students in that age group.

“It might not have changed their minds but it should be a transparent process,” Nowacki said Tuesday.

Penny Rashin, chairman of the Saxe Building Committee, said that in the next year a consultant will evaluate whether the school cafeteria is large enough to accommodate all students.