Stevenson High School officials are moving ahead with a roughly $25 million plan to expand the Lincolnshire school's East Building.
At least 20 classrooms or other teaching spaces could be included in the three-story addition that's been proposed. Most would be for science and foreign language classes.
Construction could begin this fall and be completed ahead of the 2019-20 school year.
A funding plan hasn't been finalized, but officials insist there are no plans for a referendum requesting a tax-rate increase.
"Funding would either be through existing funds or perhaps (loans)," spokesman Jim Conrey said.
School board members informally voiced support for the project Monday during a site and facilities meeting. Formal board approval is expected in March, after additional committee meetings and a review of building plans by Lincolnshire officials.
A public forum about the plan is set for 6 p.m. Jan. 19 at Stevenson's administrative center, behind the school at 1 Stevenson Drive.
Officials have been discussing a possible expansion for months, prompted by rising enrollment projections. More than 4,100 students now attend Stevenson. Enrollment is expected to reach 4,300 by 2019 and could hit 4,500 by 2025, officials have said.
Those are important thresholds for Stevenson, which is the largest high school in Lake County.
"At 4,300 students, we will exceed our capacity for science labs. And at 4,500, we will exceed our capacity for general classrooms," Superintendent Eric Twadell said.
The estimates are based on rising enrollments at the elementary and middle schools that feed into Stevenson, and increased residential construction in Lincolnshire and Buffalo Grove.
If the expansion happens, officials hope to shave more than $1 million from the project's cost with a green energy grant from the state.
Solar panels, a rooftop greenhouse and classroom, and walls on which plants would grow are among the environmentally friendly elements that could be incorporated into the project and attract that grant money, Conrey said.
Stevenson has a history of such energy-saving features. A garden above an environmental science classroom absorbs sunlight and keeps the room cooler, and solar panels generate power for a different science classroom.
Because of those and other efforts, Stevenson has been certified a gold-level facility by the U.S. Green Building Council's Leadership in Energy and Environmental Design program.