As the Smithsonian Institution’s undersecretary for history, art and culture points out, the Hirshhorn Museum and Sculpture Garden in Washington DC seldom plays host to rock music. Nor, one suspects, does it regularly get guest speakers who swear to quite the degree that the gentleman seated beside him on the stage does. There are a lot of well-worn cliches about Dave Grohl, that a few minutes in his company makes clear are well-worn only because they’re true. Every writer who meets him is apparently legally obliged to call the Foo Fighters frontman The Nicest Man in Rock, and it turns out they may well have a point: he is warm, charming, funny and abundantly, Tiggerishly enthusiastic about everything from the dancing of Future Islands frontman Samuel T Herring (“there’s something about confidence in a man like that that makes the ladies want to throw their panties at his face”), to his teenage obsession with “fucking Psychic TV”, to a video he’s got on his phone of his eldest daughter belting out Katy Perry’s hit Roar: “Look at that, man!” he yells delightedly, jabbing a finger at the screen. “Singing from the fucking heart!”

There’s the line how about his legendary bonhomie and inability to decline an invitation to pick up his guitar or drumsticks and jam has left him one of the best-connected men in music, which is also true: “I was the one punk rock kid in my high school, but rather than be an outcast, I was everybody’s friend. I could hang out with stoners and nerds and jocks, I didn’t have a problem with that,” he says. “People are people, I don’t give a shit. You could be Demi Lovato or the fucking drummer from Pantera – I don’t care, let’s have a drink!”

But one thing that no one seems to mention is that Grohl is one of rock music’s most dedicated, gleeful and indefatigable swearers. No sentence is too insignificant for him to try to insert the word “fuck” into, up to and including responding to a query about whether he minds if you smoke while interviewing him: “I couldn’t give a fucking shit!” he cries. His answers to the undersecretary for history, art and culture’s studious enquiries about the roots of the Washington punk scene and the current state of the music industry, meanwhile, are delivered in language that you suspect differs markedly from that ordinarily used by the Hirshhorn’s guest speakers: it may be that when the writer and literary critic Lewis H Lapham turned up the previous week to discuss art that offers prismatic vantage points into the suspension and attenuation of time, he also said “fuck” every other word and addressed the undersecretary for history, art and culture as “man”, but the expression on the undersecretary’s face strongly suggests otherwise. The audience, which contains the four other members of the Foo Fighters, loves every minute.

Grohl has been given the opportunity to swear onstage at the Hirshhorn Museum as a result of Sonic Highways, an HBO series directed by Grohl (showing on BBC4 in the UK), that not only documents the Foo Fighters’ attempts to record their eighth album in eight different studios around the US, but also tells the stories of music scenes in the various cities. Each track on the album features guest musicians from the cities in question and lyrics based on the interviews Grohl conducted for the series: the latter approach, he says, has the unexpected but welcome side-effect of stopping people asking the previously perennial question of whether any of the songs on the new Foo Fighters album are about Grohl’s time in Nirvana and/or the death of Kurt Cobain.

The documentaries are very good, far from the usual record-label sponsored puff-pieces that accompany a new album by a major artist, the cast testament to the breadth of names in Grohl’s address book: it’s hard to think of many other musicians who could solicit contributions from Bad Brains, Dolly Parton and Barack Obama. Grohl has known the latter since the Foo Fighters performed at the 2012 Democratic Convention and apparently sold him on the idea of appearing after noticing a copy of Bob Dylan’s collected lyrics on a shelf while “snooping around” the White House. “He’s cool, man!” enthuses Grohl. “He is very cool. You could sit and have a conversation with him just as we’re having right now. He’s genuine, he looks you in the eye. He knows music and he knows people, so he was an obvious choice, I think.”

He is disarmingly frank about the reasons behind the documentary, and indeed the plan to record the Sonic Highways album in eight different cities (his initial plan was to record it in eight different countries, but “you get the phone call that goes, ‘Do you know how much that would fucking cost?’”). “Complacency and feeling stagnant drives bands into the ground. I mean, it’s a creative endeavour and when it becomes the opposite it’s not much fun. We’re 20 years in and it’s a priority that we continue to enjoy it and love it, you know? But every day I have some harebrained scheme to fucking put on a Fourth of July show or a new video idea or a new project, and I have the opportunity and resources to do these things. I can tell my guys: ‘Here’s what I think we should do, it might sound crazy but I know we’ll pull it off,’ and they trust me to do it. I think they just sort of imagine that I’m enough of a hyperactive child and I don’t take no for an answer, so I’ll find a way to make it happen.” He smiles. “I already know what we’re doing for the next record and nobody’s done it yet and I can’t fucking wait to do it, but that’s years down the line.”

For all Grohl’s enthusiasm for the Foo Fighters’ ongoing career, and indeed their mammoth success – at last count, they had sold something like 11m albums – it is hard not to notice a certain wistfulness in the episode of Sonic Highways that deals with the Washington DC punk scene. Grohl grew up in the Washington suburb of Springfield and, before he joined Nirvana, was the drummer in the DC punk band Scream. He misses the sense of community of that scene, he says.

“There really weren’t too many musicians or bands that imagined life outside of the Washington DC music community. There was no music industry there, there was just this sense of camaraderie, everyone knew each other. Now you have famous musicians locking down a backstage area at a festival so they can go up onstage. It’s like a power trip or something. I’ve written letters to musicians before after I’ve got stuck in their fucking lockdown, like: ‘Dude, come on, we’re all in this together.’ Maybe people just don’t understand that there is an alternative to what you would imagine a rock star to be. You don’t have to have a needle hanging out of your arm, you don’t have to fucking lock down a festival backstage. Why not just go fucking knock on everybody’s door with a bottle of whisky and say: ‘Hi, I’m Dave, how are you? Nice to meet you,’ and see who’s going to fucking join the party? That’s the first thing I do.”

Words: Alexis Petridis