FAIRFIELD — The seemingly staid great lawn of the Pequot Library shook with sound Thursday evening when the School of Rock House Band took the stage for a free concert.

“We’re here to attract attention and to support the library,” said music director Frank Perrouna.

The band offered a powerhouse mix of Led Zeppelin, Steely Dan, Van Halen, Soundgarden and more.

Chief librarian Christine Catallo said the band played at the library’s Valentine’s Day fundraiser earlier in the year as well.

“They were so incredible, I thought we needed to invite them back,” she said, noting she hopes to have them back again in the fall.

In its 12th year, the Fairfield-based school has seen around 4,000 students come through its doors, ages 7 through 18. It also offers classes for adults in the evenings.

As well as being a place to learn music, general manager Evan Rapp said School of Rock is also a community for young people to discover who they are.

“They can just be themselves and succeed and expand their peer group to a much wider group than they would ordinarily find,” he said.

Perrouna emphasized that while the House Band students provide a professional-quality concert for their fans, the real purpose is to give each of them individually a chance to expand their experience and grow in their craft — be it guitar, bass, keyboards, drums or vocals.

“I’m pretty sure it’s the best music school in the world,” he said.