Mundelein High School board members got their first glimpse Tuesday night of an architect's vision for a $21.8 million building expansion.
Architect Scot Parker, of Legat Architects, presented his designs for the project, which calls for a three-story addition that would be built in a courtyard near the center of the school.
Most of the 24 classrooms planned for the space would be for the science department.
As part of the project, classrooms in the existing building would be repurposed into math and special education classrooms and offices, Superintendent Jody Ware said.
A state grant would cover up to an estimated $7.4 million of the project's cost. The rest of the cash likely would come from a loan.
A tax-rate increase will not be necessary, officials said, nor will the board need to ask voters to approve the project. Officials likely will extend existing debt.
"It's almost like refinancing your mortgage," board member Al Hitzke said.
This proposed expansion was not included in the $10 million construction plan voters approved in April 2011. Those projects included roofing and bathroom repairs, the installation of artificial turf on the football field, and other efforts.
If the school board approves the new project, it will be the campus's biggest expansion since 1995, when voters approved a $12.5 million project that included new classrooms and a new library.
Construction could begin in summer 2015 and conclude one year later.
The board took no action on the plan Tuesday. It could vote on the proposal in January.