The Cajundome is preparing for its most extensive renovation in three decades — a $20 million makeover that will bring new seating, new lights, a rejuvenated roof and host of other upgrades.

Cajundome Director Greg Davis laid out the details in a Tuesday ceremony to mark the 30th anniversary of the facility, which opened Nov. 10, 1985.

He said the Cajundome will close in May 2016 for the six-month renovation project and reopen in December.

Plans call for replacing the original 10,000 seats and adding 1,000 seats to bring capacity for concerts up to 11,000.

The new seats will be all black — in place of the current mix of orange and white — and the arena’s 1980s-vintage lighting will be replaced with new LEDs that allow for a tighter focus on sports games and performances.

Davis said the improved lighting combined with the nonreflective black seats are meant to transform the experience for the audience.

“Arenas now are not designed based on what people see when they walk in. They are designed based on what happens when live events occur,” Davis said. “The lights that hit the stage will be totally focused on the stage and not bleed into the seats. It’s going to be a much more spectacular experience.”

The bulk of the roughly $20 million project price tag is for the seating and related structural changes, lighting and renovations to restroom and lobby areas.

About $1.2 million will be used to clean and seal the Cajundome’s massive roof, washing away the mildew that has darkened the dome and bringing back its original pinkish hue, Davis said.

In all, it will be the biggest upgrade in the Cajundome’s history.

The only comparable project would be the $18 million addition of the Cajundome Convention Center, which opened next to the Cajundome in 2002.

“Nothing would even come close to what we are doing now,” Davis said.

At Tuesday’s event, several local leaders and state officials who had a role in the birth and growth of the facility were honored, including former University of Louisiana at Lafayette President Ray Authement, former Lafayette Mayor Dud Lastrapes and former Govs. Kathleen Blanco and Edwin Edwards.

“I have to confess: I’m in favor of anything that has Cajun in it,” said Edwards, who was serving his third term when the Cajundome was built in the 1980s — a $65 million project paid for with a mix of state and local funds.

Edwards, who served federal prison time for racketeering, extortion and fraud, also said it was refreshing to be recognized for more positive aspects of his public service.

“I’m just here today because it’s nice to have people say good things about me,” he said.

Davis and others reminisced about the difficulties of trying to launch a major venue in Lafayette in the mid-1980s, when the local economy faltered as oil prices tanked.

The Cajundome, which is owned by the University of Louisiana at Lafayette, has always served as the home for Ragin’ Cajuns basketball, but sports alone can’t pay the bills.

“We were in a bind. We could not convince promoters to come here and take a chance on our market,” Davis said.

He said local business leaders helped keep the Cajundome afloat in the first decade by putting their own money on the line to bring big acts to Lafayette.

A turning point came in 1995, when the Cajundome inked a deal to host the only Louisiana stop for the Eagles on the popular band’s tour that year, a big rock concert coup for what some promoters considered a second-tier market.

With ticket prices at $75 a seat, the Cajundome sold the minimum 7,000 tickets needed to cover expenses 30 minutes after the box office opened, Davis said.

“That captured the interest of the entire nation,” Davis said of out-of-town promoters.

It’s a concert City-Parish President-elect Joel Robideaux remembers well.

“I had tickets to go the Eagles concert, but my wife had the audacity to go into labor,” he said.

Robideaux also remembers an apology from the doctor. “He said, ‘I’m sorry I was late. I was at the Eagles concert.’ ”