Norwich — Representatives from 23 construction, architectural and engineering firms attended Friday’s mandatory pre-bid conference and tour of 13 schools in the city’s search for a consultant to study the entire district for possible restructuring and consolidation.

The study is being sought by the School Facilities Review Committee, charged with investigating possible consolidations of buildings, restructuring of grades and long-term efficiencies.

The committee was established in an effort to avoid hiring an outside consultant but the group quickly decided it needed professional services.

City Purchasing Agent William Hathaway told participants city officials would negotiate a schedule for completing the study, but school officials hope to have any renovation or construction bond questions ready for the 2016 fall election ballot.

The firms will receive information about the 15 buildings, their ages, acreage and other details prior to the bid deadline of 2 p.m. on Sept. 3.

During Friday’s opening question-and-answer session at Kelly Middle School, possible bidders learned of the many complexities associated with the city’s pre-kindergarten through eighth-grade district, both with the aging buildings and the educational system.

In recent years, consolidations and educational structure changes have been based on last-minute budget cuts rather than long-term planning, Superintendent Abby Dolliver said.

Five years ago, the system closed two elementary schools, Bishop and Greeneville, and Dolliver said she still gets complaints from Greeneville families about the loss of their neighborhood school.

This summer, more budget cuts led to restructuring the middle schools into a sixth-grade academy at Teachers’ Memorial School and a seventh- and eighth-grade junior high at Kelly Middle School.

The district has two preschool early learning centers, seven elementary schools, two middle schools, the sixth-grade academy and the junior high school. It also runs a regional adult education center and a special education program for elementary school-age students.

Central administrative offices are located in a historic former school. Dolliver told the group she would prefer her office to be centrally located at a school building — Kelly Middle School for example, she said — but there isn’t space.

Restructuring the district by age group has become problematic as well, because the John M. Moriarty and Wequonnoc elementary schools recently were converted into intra-district magnet schools with federal funding.

District School Business Administrator Athena Nagel said transportation costs have become a big issue, with the movement away from neighborhood schools and the need to transport students to many more “schools of choice” throughout the region.

And three schools that got state and federal school improvement grants have extended school days, further complicating bus transportation, Nagel said.

Even the answer to whether Norwich has stable enrollment totals proved complicated.

The district has varied little from the annual total of 3,800 to 4,000 students, but throughout the school year, about 30 percent of the student population will change with incoming and departing students, Dolliver said.

The John B. Stanton School alone had 100 new students come in through the course of the last school year and another 100 students depart.

Some move from one school to another within the city, while others move out of the city, out of the state and even out of the country.

“It severely impacts our testing,” Nagel said. “If we had larger facilities, students wouldn’t have to change schools as much.”

c.bessette@theday.com

Twitter: @Bessettetheday