Located on the National Mall in Washington, DC, the Smithsonian Hirshhorn Art Museum (SI HMSG) remained operational during repairs to the envelope with a limited footprint for construction activity. The 30,800 square foot remedial roofing project included the removal of two existing built-up roofs and the application of Monolithic Membrane 6125® in a reinforced hot rubberized asphalt Protected Membrane Roof Assembly, which incorporated an additional layer of protection board beneath layers of drainage board and insulation. The Smithsonian Institution can now rest easy knowing that their new watertight roof will be protecting the Hirshhorn Museum and Sculpture Garden’s collection of modern art for many years to come.