When “Roger Waters The Wall” (Picturehouse/Fathom Events) is screened on Sept. 29 for one night only at more than 2,300 theaters world-wide, the new two-hour film will pair gripping concert footage with an emotional documentary.

The concert footage was filmed between 2010 and 2013, during Mr. Waters’ stadium performances of “The Wall,” a self-described anti-tyranny rock show originally written by Mr. Waters for a 1979 album by his band, Pink Floyd. The documentary segments follow Mr. Waters on his 2013 drive from Hampshire, England, to Arras, France, and then to Cassino, Italy, to visit the gravesites of his grandfather, who died in World War I, and his father, who was killed in World War II.

When released in 1979, “The Wall” included Pink Floyd’s only No. 1 hit single in the U.S.—“Another Brick in the Wall, Part 2.” The four-minute song— with its throbbing bass line, thumping beat and teen chorus—topped Billboard’s pop chart in March 1980, where it remained for four weeks. Mr. Waters, 72, recently talked about the writing and recording of “Brick 2” as well as the two other parts of the “Brick” trilogy and a new “Brick 4.” Edited from an interview:

Roger Waters: For much of my life, I have been defensive. My new film [“Roger Waters The Wall”] is the start of an attempt to come out from behind my defenses and declare my vulnerability and acceptance of others. I have this huge desire to nail my colors to the mast of something that isn’t about confrontation but about cooperation.

The idea for “The Wall” came to me in 1977, during Pink Floyd’s “Animals” tour. Toward the end of the tour in July, a few jerks in the audience at Montreal’s Olympic Stadium set off fireworks, interrupting the show. It was more than distracting, it was rude and I told the audience. Things got a bit out of hand when someone tried to scale the barrier at the front of the stage and I spat in his face. The event and my behavior made me think about my relationship with the audience and the obvious wall between some of them and some of us on stage.

Watch a clip from 'Roger Waters The Wall,' a concert film featuring the co-founder and primary songwriter of Pink Floyd. Photo: Picturehouse Entertainment

After the tour, when the band had had a chance to rest, I thought about what had happened and developed an idea for a large-scale rock show: A huge theatrical brick wall would be erected between the band and the audience to express the alienation between those in the seats and what we were trying to do.

As I thought about the idea, the wall became a metaphor for some of the mechanisms people and institutions use to keep the rest of us under their control and dictate how our lives should be led—but I didn’t want to seem conspiracy-theory about everything.

I also wanted this wall to stand for the emotional barrier we build around ourselves as individuals, with the bricks representing difficult things that have happened to us over time. At one point, I drew a brick wall on the back of a white envelope. The lyric for “Brick 2” was the progeny of that idea.

In late 1978, I called a meeting of the band at our Britannia Row Studios in London. By then, I had recorded two concept-album demos that were each about 50 minutes long. I also brought along texts that outlined the concepts I had in mind.

At the studio, I told the band—Dave [Gilmour], Rick [Wright] and Nick [Mason]—that I had written two theatrical works. One was “The Pros and Cons of Hitch Hiking” and the other was “The Wall.” After we listened to the demos, they picked “The Wall,” which I thought was a good choice since it had more universal concepts.

I had already written what would become “Brick 2” at Bourne Hill House in Horsham, West Sussex, England, where I was living at the time. I had an old 16-track analog mixing board that came from Criteria Recording Studios in Miami. I used it to record my demo of “Brick 2” and a number of other songs for “The Wall.”

The words and music were written as I strummed on a six-string acoustic guitar. The song flowed straight out of me in a minute and a half. It only had a single verse and a chorus. On the demo, I accompanied myself. (Mr. Waters sings the rhythmic acoustic guitar introduction and then the lyrics, “We don’t need no education / We don’t need no thought control.”)

Pink Floyd, left to right, Rick Wright, Roger Waters, David Gilmour and Nick Mason, in Los Angeles in 1980 Photo: Neal Preston/Corbis

The lyrics were a reaction to my time at the Cambridgeshire High School for Boys in 1955, when I was 12. Some of the teachers there were locked into the idea that young boys needed to be controlled with sarcasm and the exercising of brute force to subjugate us to their will. That was their idea of education.

When the band first recorded “Brick 2” in the studio in early 1979, I thought of it as just a short thematic interlude in “The Wall.” After we finished it, we realized the song was catchy and had bigger potential, but we weren’t quite sure how to build it out. We tried a guitar solo over the verse, but the song was still too brief.

It wasn’t until “The Wall” was almost finished that I thought it might be good to get a bunch of English kids to sing the chorus, to animate the lyrics. We were in Los Angeles at the time finishing the album at Producers Workshop studio with [producer] Bob Ezrin and [engineer] Brian Christian. So we sent the 24-track studio tape of “Brick 2” to [engineer] Nick Griffiths at Britannia Row Studios and asked him to find some kids to sing on it.

Nicky found the kids at the Islington Green School in North London, near our studio. He put together about 25 students between ages 13 and 15 and overdubbed them singing several times, so it would sound as if there were many more of them. I originally thought we’d use their voices as background for the lead vocals Dave and I had recorded, but the sound we heard on the tape when it came in was so emotionally powerful that we let them sing their part alone.

Photo: Britta Pedersen/European Pressphoto Agency

To hear those kids from a not-so-affluent part of London singing the lyrics took my breath away. By adding those voices, Nicky had made the song visceral and deeply moving in a very serious way. Letting them sing alone and adding David’s guitar solo expanded the song to four minutes.

In my recollection it was my idea to add the kids singing, but human memory is a fallible device. Bob Ezrin might say it was his idea. Other members of the band might say it was theirs. I have no interest in arguing with any of them about any of it, as what we do know now, for certain, is that we’ll never know.

The song ran slow, almost like a chant or mantra, at 100 beats per minute. To give it a bit of punch, Bob Ezrin added a kick drum on every beat, which made the song a different animal than something strummed on an acoustic guitar. It’s not a disco beat, as many people have said, but more of a heart beat. It’s very cool.

Featuring the song once on the album was never my intent. My demo was meant as a thematic interlude that would appear in different forms in different places to transition from one section to another. I had written lyrics for three parts, with slightly varying orchestrations.

Roger Waters in Norway in 2011 Photo: Nigel Waldron/Getty Images

For example, “Brick 1” starts with the lyrics, “Daddy’s flown across the ocean / leaving just a memory.” It’s about my father’s death, which was my first “brick.” “Brick 2” is my educational thing. And “Brick 3”—“I don’t need no arms around me”—was used after “The Wall’s” main character has a mental breakdown following his wife’s betrayal. What can I tell you? In relationships, stuff happens, and sometimes we feel we’re immune even to the healing power of loving arms. We don’t always see straight.

Then again, sometimes we do see straight. When Nick Griffiths sent me the multitracks of the song from London, I was in Los Angeles and had Brian stick it on the tape deck. “OK” I said, “Push all the faders up.” As soon as the song came on, it was like, “Whoa.” I knew instantly it was a hit.

After “Brick 2” was released as a single, even some intelligent writers thought it was an anti-education song and said it was disgusting and obscene. But the song was never that. It’s a protest song against the tyranny of stupidity and oppression, not just in schools but universally. It’s about the malign influence of propaganda. Obviously, I care deeply about education. I just wanted to encourage anyone who marches to a different drum to push back against those who try to control their minds rather than to retreat behind emotional walls.

In 2011, during my recent tour for “The Wall,” I was moved to write “Brick 4.” I was sitting in a hotel room somewhere in the States when it occurred to me that the Hammond organ solo at the end of Brick 2 was just filling time. I didn’t want to do that anymore, so I wrote lyrics for a new “Brick.” It became my homage to Jean Charles de Menezes, a Brazilian engineering student killed in London by the police in 2005 when they mistakenly thought he was one of the people involved in the failed Underground [subway] bombing attempt days earlier. This song appears in the movie right after “Brick 2.”

Listening to “Brick 2” today, I wouldn’t touch a thing. If you have something to do with a four-minute song that has proved to be as powerful as this one, you would have to be an idiot to tear the wings off to see what makes it fly.

Looking back, however, I realize that whenever you collaborate with others on something special, you have to be grateful that you came together. This is true about all my colleagues in Pink Floyd and Bob Ezrin, Nick Griffiths and whoever else was involved. You have to say, “Hey, we were a team.”