The concession stands are being stocked. The Falcons’ logo adorns midfield. There is a lot of cleanup still to do.

Hundreds of media members toured Mercedes-Benz Stadium on Tuesday and saw a $1.5 billion building that looks just about ready for action.

And the action arrives soon: Stadium officials expect more than 50,000 Falcons and Atlanta United season-ticket holders to attend an open house Saturday, and the stadium will hold its official opening with a Falcons-Arizona Cardinals exhibition game Aug. 26.

About 10 NFL staffers were on site Tuesday, making a final test of the stadium’s readiness for football by checking many aspects of game-day operations.

A marathon project in the works for a decade, and under construction for 3 ½ years, is closing in on completion.

“It’s really hard to imagine that you get to the finish line,” said Falcons president and CEO Rich McKay, who has been immersed in the project since 2007. “There were many times where you felt good about the progress. But progress is one thing, and getting to the finish line is another.

“I think the building is going to live up to what we said it was going to be.”

McKay spoke in the Falcons’ locker room, which has nine TV screens. Across the stadium, Atlanta United president Darren Eales showed off his team’s locker room and looked forward to the players practicing on the stadium’s artificial turf Saturday.

“It’ll be the first chance for all of our players to actually see the finished stadium,” Eales said. “Saturday, when our players come in here, it’s going to be a special moment. Because they’re going to go out and train on that field and realize how lucky they are to be on a club that is going to be playing in one of the top stadiums in the world.”

Stadium officials showed off some of the signature features of the 2-million-square-foot building Tuesday, such as the massive halo-shaped video board, the 101-foot-tall video column and the wall of windows framing a view of the city behind one end zone. But there was no new information about when the complex and problematic retractable roof can be opened for events.

The roof was in the closed position Tuesday, where it will remain through Aug. 26. The plan is to slowly open and re-close the roof in the days after that to continue testing. But officials have indicated it will be at least October before the roof is sufficiently automated to be opened for events.

Before automation, opening and closing the roof is much too time-consuming to be an option on event days, taking hours or even days. After automation, the roof is supposed to open or close in about 12 minutes.

“Is it mechanized yet where we can … open it for an event? No,” McKay said Tuesday. “Will it be? Yes, in the near future. I don’t want to give a date. … I’m just going to say let’s wait and see.”

“We’re still in the process of going through and fine-tuning the automation,” said Bill Darden, president of Darden & Company, the project management firm overseeing development of the stadium for Falcons and Atlanta United owner Arthur Blank.

Darden said he expects games to be played with the roof open “this year in the fall sometime … for both soccer and football.”

Otherwise, everything looks ready, or close to it.

Punch-list items are being worked through in the suites and other places. A massive air-conditioning duct was dropping condensation on seats in one spot.

A curtain system that can be used to seal off the upper deck for Atlanta United games will be installed this week or next.

“We’ve got a lot of cleaning to do,” Darden said. “Today, when I was walking in, they were unloading food as fast as they can. We’re still putting signage up in some key areas.

“We’re just detailing out the last-minute things.”

KEY DATES

Early events at Mercedes-Benz Stadium include:

Saturday: Open house for Falcons and Atlanta United season-ticket holders, including an Atlanta United practice

Aug. 26: Falcons exhibition game vs. Arizona, the stadium's official opening

Aug. 31: Falcons exhibition game vs. Jacksonville

Sept. 2: Alabama vs. Florida State in a Chick-fil-A Kickoff college football game

Sept. 4: Georgia Tech vs. Tennessee in a Chick-fil-A Kickoff game

Sept. 10: Atlanta United vs. FC Dallas in the stadium's first soccer match

Sept. 17: Falcons vs. Green Bay in regular-season home opener