An $18 million activities center is going up at St. Thomas Academy on Interstate Hwy. 494 in Mendota Heights.

The large addition -- about two-thirds the size of the existing building -- is the first expansion since the private Catholic boys' school opened in Mendota Heights in 1965.

The new activities center, planned to include four athletic courts, a new band room and new classrooms, will help the school compete for new students and provide a better education for the 540 already enrolled in grades 7 through 12, school officials said.

"It is a huge step forward for the school to have those spaces," said Rick Anderson, chair of the St. Thomas Academy Board. "This is about the future, and securing the future of the school."

The exterior shell of the building is expected to be closed to the weather by Nov. 15 and the courts finished by next June.

One hitch, however, is that construction began with $13.5 million of the $18 million that is needed to complete the plan. Fundraising continues in hopes of finishing all the interior space.

"What we can pay for with that $13.5 million is the entire exterior structure," along with four courts with seating for 1,500, interior halls, restrooms and a lobby, said Chris Ritten, director of institutional advancement.

The school has been touched by the generosity of alumni to the building campaign, Ritten said. Continuing fundraising will shift to parents of students.

"There will be a much more concerted effort this coming year within the parent community," Ritten said. "The building is going up and they can see the benefit to their kids while they are students here."

If the school is able to raise the extra $4.5 million, construction will proceed on a new high school locker room, a fitness center, two health classrooms, team meeting space, two coaches' offices, a trainer's room and a wrestling room, Ritten said.

Also planned, if the extra money can be raised, are two new art studios, a computer graphics room, a large band room and choir rooms. All together, seven new classrooms would be built and nine refurbished.

Further in the future, the school would like to build a new pool and new front entryway.

To decide what to include in the activities center, St. Thomas officials toured public and private high schools, including a new activities center built at Breck School in Minneapolis.

Students now take part in many activities and "it becomes important to have the adequate facilities to meet that need," said Tom Schreier, a St. Thomas alumnus and former chair of the board.

"While other schools had made major renovations, St. Thomas hadn't," he said. "I would look at the expansion as allowing us to catch up."

Laurie Blake • 952-746-3287