Crews are repairing exterior panels on U.S. Bank Stadium as the Minnesota Vikings prepare for their second season in the facility.

The $1.1 billion stadium in downtown Minneapolis was completed more than a year ago, but workers are still fixing panels in about half a dozen spots.

The durability of the panels has long been a concern. Panels came loose during storms in July 2016 and last March. Earlier this year, water seeped through and created puddles in various places.

Finance & Commerce reports that about 10 percent of zinc panels covering the outside of the stadium are being repaired. The work is expected to wrap up next month.

The Minnesota Sports Facilities Authority says the repairs are covered under warranty, and there is no cost to taxpayers.

The 52nd Super Bowl will be played at the stadium in February.