Some zinc panels have come off U.S. Bank Stadium this week as part of a routine inspection to repairs made on the $1.1 billion building's moisture barrier.

About a year ago, contractor M.A. Mortenson found problems with moisture seeping through the exterior enclosure of the stadium. The contractor announced the problem in February, as well as its plans to replace the moisture barrier and cover the costs of up to $4 million.

Now that the work is done, representatives from Mortenson, the Minnesota Sports Facilities Authority and the building's design team are inspecting the corrective work.

Temporarily removing exterior panels on various parts of the building allows workers to make sure the new moisture barrier is working, according to a Mortenson spokesman. The inspection will take a few days, but will be complete before the Vikings return. The Vikings don't play at home until they host the Detroit Lions at noon on Nov. 6.

The moisture barrier was the most costly construction problem with the building that opened in August.

The other problem concerned flapping zinc panels on certain points of the building after heavy storms last summer. Those panels initially were held in place only along the bottom edge. Workers spent several weeks reinforcing the panels at the top.

In its debut year, the stadium has yet to be tested in a full cycle of seasons and still could face unforeseen problems. The stadium is under a two-year warranty with Mortenson.

Rochelle Olson • 612-673-1747 Twitter: @rochelleolson