Sadie Cassellius laughs when you ask her about her old school.

"Well," she says, "It was really small, there was just one hallway so you couldn't get lost very easily, and it used to be an elementary school, so everything was very short and small."

When you ask the 11th-grader her about her new school, she sighs.

"It's beautiful," she says. "I just love it a lot. It's so sophisticated and elegant, and it's bigger, and there's just a lot of feeling of openness to the building."

Students at the private Trinity School at River Ridge moved into a brand new, $19 million school in Eagan on Tuesday, 21 years after the school opened in a former Bloomington elementary school.

The Christian school, which serves 365 students in grades 7-12, will not only have its first gymnasium -- home sports games have been played elsewhere since the school opened -- but it will have its first science labs and athletic fields.

"It was time to move," Cassellius said.

In 2004, according to headmaster William Wacker, the school was "about five days" away from commissioning an architect to expand the Bloomington building, which would have gotten a gymnasium. But the school -- which was in line with the Minneapolis-St. Paul airport's new runway -- went to a meeting of the Metropolitan Airports Commission because the school was set to receive just under $7 million for sound abatement projects to reduce airplane noise.

But an official at the meeting suggested something more drastic: "They said, 'Why not just take the money and relocate?'" Wacker remembers. "And that got us thinking."

The school sold the former River Ridge Elementary for about $5 million and used that money, plus $7 million from the Metropolitan Airports Commission, $1 million in savings, and about $6 million from a capital campaign to pay for the new building.

The building is about 96,000 square feet; the old building was about 60,000. There are four science labs, an art room, a music classroom and an auditorium. It has 31 classrooms.

The building also houses office space for "People of Praise," an ecumenical outreach group that started the Trinity schools -- there are two others in the United States -- in 1981.

The school puts a lot of weight on its science curriculum and a classical curriculum. The school requires its students to learn Latin, which led architect David Cihasky to include elements of southern Mediterranean design, such as columns at the schools' two entrances, a low-sloping roof with red shingles over the classroom wings, and a wide-open atrium near one of the entrances.

Schools, Cihasky said, have to be designed differently than standard buildings "because of the abuse they take," although he said the inside of Trinity is not made of concrete blocks, like many public schools. The classrooms feel more like conference rooms, he said, because many classes are more like discussions or seminars.

Because the lack of concrete means sound can travel easily between the rooms, Cihasky hung sound insulation that weighs several pounds per square foot between the walls of the classrooms.

Some students are apprehensive about the effect a big, new building will have on the culture of unity in the school, Cassellius said. But that doesn't dampen the anticipation.

"I hope the school changes school spirit," she said. "Last year, we actually got a mascot, and now we have a gym so we can host home games ... We're just really excited."

Emily Johns • 952-882-9056