Leaders of the Mercedes-Benz Stadium construction team delivered an update on the project to a state board Tuesday, stressing the complexity of the steel structure for the roof of the Falcons’ new home.

“It has been quite the challenge, and it has certainly taken the (steel) fabricators longer than they would have liked,” Wayne Wadsworth, principal in charge of the Holder Hunt Russell Moody joint venture, the stadium’s general contractor, told the Georgia World Congress Center Authority board.

Falcons owner Arthur Blank cited the complexity of the roof structure when he disclosed in an interview with The Atlanta Journal-Constitution last month that the target date for opening the stadium has been pushed back three months to June 1, 2017.

Barring further delays, that won’t prevent the Falcons from opening the 2017 season in the stadium, but it will force Blank’s new professional soccer team, Atlanta United, to play on the road for at least the first three months of its inaugural MLS season.

In the presentation to the GWCCA board Tuesday, Wadsworth said all 18,000 “shop drawings” for the fixed portion of the stadium roof will have been processed and approved by the end of this month, calling that “a very major milestone.”

“(It’s) a huge sigh of relief to have that in our rearview mirror,” he said. “We’re now focused on the operable (roof) panels and on the video halo structural steel.”

The $1.4 billion stadium is under construction next to the Georgia Dome. Two of the signature features of the new stadium are the retractable roof, which is supposed to open and close in seven minutes, and the 58-foot-high oval video board, which will be built into the roof opening and will surround the field.

GWCCA board member David Allman asked Wadsworth and Bill Darden, the Falcons’ stadium project executive, the target date “for pushing that button” to see the retractable roof in action for the first time.

“It’ll probably be late first quarter of 2017,” Wadsworth replied. “It’ll be moving around before that in pieces as we get it constructed, but that will be under contractors’ control as opposed to the magic button.”

Wadsworth and Darden also updated the board on plans for demolishing the Georgia Dome after the new stadium opens.

A contract to demolish the Dome likely will be awarded by August, they said. Pre-qualification of prospective bidders is scheduled to be completed in March, followed by a bid process.

Wadsworth and Darden said the Dome likely will be demolished by a combination of implosion and mechanical means (such as wrecking ball).

“There are some firms that want to implode more of the existing structure than others,” Wadsworth said. “The team that we select will be part of the design and the engineering of the right way to take it down.”

Darden told the AJC in an interview last month that the demolition process likely would be completed late in 2017 or early in 2018.