The 36-year-old Louisiana Superdome is getting its biggest overhaul since Hurricane Katrina tore away a lot of the roof and flooded the arena with millions of gallons of water.

And it comes at just the right time as America's oldest domed stadium still called home by an NFL team gets ready to play host to college football's BCS Championship in 2012, the men's college basketball NCAA Final Four that year and the Super Bowl in 2013.

Gone will be the groundlevel oval familiar to Super Bowl viewers. In comes a jazzier, new rectangular configuration. Workers are also adding thousands of larger leather seats with cupholders, new concession stands and other upgrades as part of an $85 million makeover.

Doug Thornton, the vice president of the Dome management company SMG, said fans can expect a very through upgrade.

"There is definitely going to be a wow factor," Thornton said. "When you come in the door you are going to see a completely different Dome. The entire configuration on the lower bowl will be changed from an oval to a rectangle."

The first phase of the upgrade has already added 16 new private box suites and a new press box.

On Wednesday, a giant excavator demolished metal risers that had long supported the second-tier seating inside the vast stadium, which opened in 1975 and later required major repair work after Katrina flooded much of New Orleans through burst levees in 2005.

That year the dome was best known for hosting some 30,000 hurricane refugees clamoring for rescue. In the aftermath of the 2005 storm, 9.7 acres of Dome rooftop had to be replaced, 58,000 seats cleaned, some 10,000 additional seats replaced and 3.8 million gallons of water extracted from the Dome and its garages.

On Wednesday, workers with huge saws and crowbars busily reduced the risers into piles of debris to be hauled away.

The current work will complete a renovation project that came as part of the 15-year lease extension between New Orleans Saints owner Tom Benson and the state of Louisiana that was reached in 2009.

The new configuration will allow the addition of 3,500 new seats on the ground level and construction of a new "club area," with 4,500 large leather seats with cup-holders — including a private club for the use of those ticketholders.

All told, the plan also calls for the remodeling of 137 suites and four club lounges, widening the plaza concourse from 18 feet to 60 feet and adding concession stands.

The upgrades are expected to boost the revenue that Benson is able to generate in the Superdome and reduce the state's obligations to the club. Officials say renovation work is scheduled to be completed by June 20 just before a major event, the Essence Musical Festival, is scheduled to be held at the venue starting July 1.

"We'll have it done," Thornton said. "We unfortunately picked up a couple of weeks we didn't think we'd have."

The bonus time came when the last Super Bowl champion Saints were knocked out of the playoffs. Work was not scheduled to begin until Jan. 24.

Including the $225 million spent to restore the Superdome after Katrina, officials say Louisiana will have spent $305 million on the building since 2005.

The latest move is expected to keep the Superdome competitive for future sporting events and comes as other aging arenas have eyed or are undertaking improvements. Among them is the venerable Rose Bowl stadium. Last year the Pasadena City Council approved a $152 million renovation plan for that 88-year-old stadium to boost luxury seating, add more concession stands, a new scoreboard and other improvements for the site of the annual Rose Bowl game.