Drone will make sure U.S. Bank Stadium stayed dry inside this winter

A drone will inspect the upper reaches of U.S. Bank Stadium's exterior to ensure that the two-year-old building endured a second winter unscathed.

Minnesota Sports Facilities Authority (MSFA) officials say they've been able to inspect the lowest 10 feet of the building, but they will use the drone to photograph the upper reaches, which go as high as 270 feet on the western prow. Moisture and loose panels have been a high- profile problem for the stadium since before the building opened in August 2016.

"We have not seen anything" to indicate additional problems, MSFA Chairman Mike Vekich said Friday.

MSFA Executive Director James Farstad added, "We expect some heavy rains in the next month and that will give us a good test."

The panels and moisture have been a visible problem. General contractor Mortenson Co. noticed moisture in the fall of 2015 and replaced a moisture barrier in the spring of 2016.

Then came highly visible — and thus troubling — problems with the signature black zinc panels that make up most of the exterior of the $1.1 billion project. Some panels loosened from high winds in the summer of 2016. Inspection and reinforcement of the panels by Mortenson lasted into fall 2017.

Taxpayers, who paid almost $500 million for the stadium, can exhale about the panels — at least for now. MSFA spokeswoman Jenn Hathaway said the building's two-year warranty with Mortenson hasn't started because U.S. Bank Stadium is still considered to be under construction.

Farstad said he anticipates numerous good proposals on what he calls the "darkening solution." Blackout drapes are needed for the men's basketball NCAA Final Four next April 6-8. The NCAA requires the building's light conditions be the same for all practices and games. The four teams that make it to the Final Four practice during the day and play at night.

Farstad said 460,000 square feet of the plastic roof and glass walls will need to be darkened. "It's a significant effort," he said.

With its glassy walls and translucent plastic roof, U.S. Bank Stadium's lighting conditions are as fluid as the sunshine and rain. On bright days, the interior light can be blinding.

The roof and the glass walls will likely require two different blackout methods, so the MSFA may choose separate vendors for each, he said.

Board Member Barbara Butts Williams suggested that at least one of four board members should be in on the interviews with prospective contractors.

Patrick Talty, general manager of the building for SMG, the stadium's operator, said the "darkening solution" will be an asset for future events, including in the summer of 2019 when some 50,000 attend the Lutheran Missouri Synod Youth Gathering. Not unlike the Final Four, a dark interior will provide more controlled lighting as the event is broadcast around the world.

Neither Farstad nor Vekich has provided a cost estimate for the project, other than to say it will be expensive but should be covered by the building's existing capital fund.

The two expect to provide the board with an update on the project at the MSFA meeting May 18.