Engineering: behind the scenes
Dennis Lipp and Bruce Carpenter, Dean Kurtz construction company workers, roll out waterproofing fabric before covering the roof of a basement with sealant at Ellsworth Air Force Base, S.D., Oct. 23, 2014. The 28th Civil Engineer Squadron engineering flight worked with local contractors to repair base structures, and has contracted 47 future base projects to be designed and constructed in 2015. (U.S. Air Force photo by Senior Airman Hailey R. Staker/Released)