This modernization was a complex, phased, and occupied historic renovation of a 1930’s National Register of Historic Places federal office building. The facility houses several federal agencies. One-half of the building remained occupied during the Phase 1 construction period which was substantially completed in February of 2008 and phase 2 completed in October of 2014. All primary systems were modernized. This project was selected to be part of GSA’s Green Proving Ground Program, which is a pilot program at the national level. The goal of this program is to test and evaluate innovative and underutilized sustainable building technologies and practices. Findings will be used to support the development of GSA performance specifications and inform decision making within GSA, other federal agencies, and the real estate industry. High Performance Green Building (HPGB) practices were implemented via change order to include a photovoltaic array system, geothermal wells, daylight dimming lighting control system, and rainwater reuse system.