There’s no such word as “perfecter.” So if Green Day’s “American Idiot” is “a perfect album,” as orchestrator Tom Kitt believes, why change it to create a Broadway show?

“My biggest concern was to make sure I was doing justice to an iconic piece of work,” he says. “The first thing was to show the band I took their work as seriously as they do. If they were after a transcription of the album, just what they’re used to, I could do that. But I felt some creative urges.”

And when Kitt has urges, they pay off. By the time “American Idiot” began a one-year New York run in 2010, Kitt had shared a Tony for orchestrating his own rock musical, “Next To Normal.” (He won a Tony for its score, too.)

You’ll hear his arrangements if you attend one of the five performances of “Idiot” this weekend, when the national tour storms into Belk Theater. Green Day supplied the raw power for the show in its 2004 concept recording, which won a Grammy for best rock album. Kitt supplied the subtler touches when it went to the stage.

“Billie Joe Armstrong and I are both big Beatles fans,” Kitt says of the Green Day singer-guitarist. “We thought back to George Martin, who didn’t write Beatles songs but added elements to change the tone.”

So the band listened when Kitt suggested that a bass line echo Bach, or the key song “Whatshername” should be stripped to piano and strings – “the emotions are kind of naked there, at the start” – before building to a wall of sound.

Martin loved strings. Phil Spector founded a career on dense, wall-of-sound backdrops for vocalists. Listen to the cast album for “Idiot,” and you hear their work and others’, including vocal harmonies the Beach Boys might claim.

“Most artists draw on their influences. We create a voice that’s a summation of all of them and, we hope, comes out as something new,” Kitt says.

“In the drug ballet ‘Last Night on Earth,’ the characters shoot up. It had to be a trippy moment, with whatever sort of beauty you can find in a moment like that. The characters are finding it, so I wanted the music to be welcoming, something that feels like it should be a friend but isn’t the sort of friend you should have. The harmonies the Beach Boys and Rufus Wainwright use felt so right for that moment, though I tried to make them my own.”

The original “Idiot,” which Rolling Stone magazine rated as one of the top 250 albums of all time, has one protagonist. In the show, written by Armstrong and director Michael Mayer, three men are co-leads.

Will stays in suburbia to work out his relationship with his pregnant girlfriend. Tunny joins the military, goes to war and comes back a broken man. Johnny goes to a city, where drugs and a woman take him in two directions. The musical adds B-sides from the concept album, a new song (“When It’s Time”) and numbers from “21st Century Breakdown,” Green Day’s follow-up album.

These elements blended naturally for Kitt, who’d been a fan since he attended Columbia College in New York City in the mid-1990s.

“I remember being struck by their showmanship,” he says. “You know when a band connects onstage, when everyone’s in sync and the audience is an integral part of that? The writing feels vibrant and new and speaks of everything you haven’t experienced yet.

“I didn’t know then that I wanted to write for theater. I was interested in being a singer-songwriter. When (a band) is producing material that makes you more desperate to get there, to make people feel the way you’re feeling, that’s a very important moment.”

Like Kitt’s “Normal,” the stage version of “Idiot” is a sung-through rock musical with almost no dialogue – but with a harder, assaultive edge. How did he vary its emotional tones, to prevent us from feeling like wrung-out dishrags?

“Going between acoustic and electric sounds certainly helps. With ‘Boulevard of Broken Dreams,’ where Johnny is getting his feet under him in the city, I started with acoustic guitar, djembe (a skin-covered African drum) and strings. In the second verse, big drums kick in, and we get more sound.

“The musicians were part of this process at every step. When an emotional moment had to hang in the air a little more, when we had to make something smaller, they were open to it. The back-and-forth couldn’t have been better.”