A new expansion will allow a Janesville private school to accept middle school students.

Rock Prairie Montessori School announced Thursday it was ready to break ground to attach two new classrooms to the back of its building at 5246 E. Rotamer Road.

Rock Prairie Montessori is a nonprofit, nonreligious school for children ages 18 months through eighth grade. It is not affiliated with a voucher or choice program and is funded through tuition and fundraising.

The expansion was driven by “growing enrollment and a grassroots call for an adolescent middle school program,” Melissa Badger, Rock Prairie director of finance and communications, wrote in a news release.

The school has 156 students, up from 80 students a few years ago, Badger said in a phone interview.

“Parents and families have been asking for it,” she said.

Parents helped form the capital campaign committee, and it raised more than $665,000.

Montessori classrooms generally are mixed age, and the adolescent program will include students ages 12 to 15—or the equivalent of seventh and eighth grades.

Along with the new addition, the school will improve and expand its outdoor play and learning areas, adding a greenhouse and an area for small animal care.

The outdoor learning lab will offer students “an enriched educational experience, combining rigorous academic inquiry with authentic experiences in real world problem-solving, service learning and entrepreneurial activities,” according to the news release.

Along with learning botany, biology and other natural sciences, the outdoor lab and animals will allow students to start, run and work at their own businesses, engage in “chores”—always part of the Montessori system—and learn about the ways in which their behavior affects the natural world, said Martha Carver, head of the school.

The school plans to start the adolescent program with an estimated 10 to 12 students, Carver said. The program will have a maximum of 25 students.