Ever since Montini Catholic High School raised its science requirements for graduates, the school’s laboratories have become more and more crowded.

On top of that, the four science rooms are originals, having been built with the school in 1966. The equipment is in sore need of an upgrade. The rooms are tiny and inadequate for interactive lab work.

But thanks to a new agreement between Montini and the city of Elmhurst, the private high school on the southern end of Lombard is due for a facelift.

Elmhurst aldermen Monday night approved the issuance of $7.5 million of private activity bonds to Montini.

The state bonds, which municipalities often issue at a low interest rates to nonprofit organizations, will allow the high school to move forward with plans to add six science labs, a technology resource center and administrative offices to the north end of the school.

The bonds also will allow Montini to refinance existing debt from its 2001 project to build classrooms and an athletic field house.

“What the bond issue provides is the opportunity to get started with building this project,” said Jim Segredo, president of Montini. “We want to break ground this spring.”

School officials had first requested help from the village of Lombard, but the village’s 2007 and 2008 municipal bonds were already earmarked for other uses, Segredo said. School officials then reached out to Elmhurst.

The city will act as the conduit issuer of the bonds, shouldering no risk in the venture, but collecting a $37,500 processing fee, said Tom Borchert, city manager.

“No Elmhurst entity requested use for the funds and Elmhurst, consistent to past practices, looked elsewhere,” he said. “This allows a good project to go forward, and Elmhurst makes a bit of little bit of revenue.”

The state dollars allow for projects that otherwise wouldn’t go forward. If the municipality doesn’t use them in a given year, the money does not carry over, Borchert said.

Montini will use most of the bonds to demolish a portion of the high school and add science rooms, a library, and administrative and athletic offices. It also will remodel the former science rooms into art studios, Segredo said.

“Our intent is not to get bigger, but to provide the needed academic and administrative facilities for the community,” he said.

Montini is raising money through private donations from parents, alumni and other friends of the school to pay off the bonds.

“We feel we have enough money in pledges and money already donated that should be able to comfortably build a building and be able to pay down the bonds,” Segredo said.

The project is the first of Montini’s three-phase “Celebrate the Future: Building on Success” campaign.