McGHEE TYSON AIR NATIONAL GUARD BASE, Tenn. - A construction worker installs a temporary ice and water barrier along the seams of the tin sub-roof atop the new classroom building here, June 16, 2015. The barrier will be in place until installation of the permanent standing-seam metal roof later this month. (U.S. Air National Guard photo by Master Sgt. Jerry D. Harlan/Released)