It has the musty smell of a frathouse, along with that institution’s weakness for the odd plushy couch. Its floors are sticky, and chipped walls reveal old wallpaper next to new band posters. There are no refunds, but plenty of until-morning shows and cheap beers, at least until iconic concert venue Webster Hall closes down for renovations after Thursday’s shows.

New ownership has promised to “preserve what Webster Hall means to the consumers and artists, but we will contemporize it,” Brett Yormark, chief executive of Brooklyn Sports and Entertainment, told The Post. The new digs are expected to open next year.

But until then, there’s plenty to praise about the historic Manhattan nightclub, long one of the city’s cheaper and more democratic late-night destinations.

Its three stages, equally distinct and loud and noisy, have featured all the greats from Bob Dylan and Harry Belafonte to U2 and Madonna, and nurtured hundreds of careers in between.

View from the stage

For Carter Reeves, 24, then a member of the pop duo Aer, Webster Hall was a welcome to New York City — and a big stage. Walking down the dingy but charming steps to the basement green room nearly a decade ago, something amazing happened: the performers, then underage, weren’t carded, Reeves remembers today. It was their first time. There was beer for the taking: “the first rock-star moment.”

Later, Reeves played and rapped as part of Aer and on his own in the Grand Ballroom, the main upstairs stage that fits (or squeezes) thousands, where the sound slaps at the walls from the stage and performers feed off the room’s energy. A maze of rumbling floors and bouncing balconies, green rooms with “every band sticker ever on the walls,” Reeves says, the place is the epitome of a New York rock club.

“There was something intimate about it,” says Mateus Falci, 25, who played keys and guitar at the venue just once as part of the live band for artist Ben Zaidi. It was the biggest stage Falci had ever played, and he says there was the sense he and the rest had to “rise to the occasion.” But he focused on the first rows, the bobbing faces, and that carried him through the performance. Before and after, he could appreciate the digs. The floor might have been creaky but it was clearly “an old beautiful spot,” from the elegant outdoor marquee to the Art Deco paneling within.

Changing with times (and the sounds)

But it wasn’t just the surroundings that made Webster Hall what it is. There was the history — the site’s roots in political activism and organizing, where Margaret Sanger marched 119 children of striking workers in 1912; where powerful union Amalgamated Clothing Workers of America were founded two years later. In later years, it became the “Devil’s Playhouse,” host to masquerade parties and costumes that gave a home to those outside the city’s mainstream, including gay and lesbian New Yorkers who could drop facades inside.

It was punky in the punk era, hard rocking before that, and always filled with partygoers looking to blow off steam or bend the rules in the Marlin Room. It was the place to go for generations of New Yorkers and visitors, from Halloween to New Year’s and most days in between. You might catch a folk or hip-hop show, dance or just nod your head until late. The artist up front might be famous or almost unknown. And the venue was basically welcoming to teenagers discretely downing a shot behind the main bar, even as it maintained its reputation for high-level music to the present.

In the waning days of the old Webster on Tuesday, a line of regulars already waited outside the venue’s black doors by the early afternoon to see the performers come in. Doors opened at 7. But Joelle Montalvo of the Bronx wasn’t going to miss Michelle Branch, playing on Wednesday for one of the location’s last days. She said she has been to some 40 shows here on 11th Street, stayed until 3 in the morning for some of them. Once, she remembered, other revelers in the basement section had jumped up to reach the pipes on the ceiling in front of the stage, hanging suspended in front of their idols and shouting back their songs. For as long as they could hold on — 20 seconds, maybe more — before tumbling down.

Montalvo, 26, sat outside waiting for showtime, chatting with another more elderly fan who regaled her of seeing the Ramones there back in the day, watching Mick Jagger walk coolly in through the front doors to watch a show. Had the venue changed much since then? Still dark, still loud.

Could it be cleaner? Sure. Maybe the stairs to the bathrooms could be rebuilt. A friend of hers had slipped and fallen at a Good Charlotte show Sunday night. The smell could be something special. But with hope the renovation wouldn’t tinker with the essential homey ingredients, the three stages throbbing and welcoming, unfussy, there for whoever arrived. “When you go inside,” Montalvo said, anticipating her entry hours later, “you know you’re going to have a good time.”