The Departmental Auditorium was constructed from 1932 to 1934 as the connecting wing between the new Interstate Commerce Commission and Department of Labor buildings. The complex of three buildings was San Francisco architect Arthur Brown, Jr.’s contribution to the government’s larger Federal Triangle development. In 1987, the Auditorium was renamed for Andrew W. Mellon, Treasury Secretary during the Federal Triangle project. Upon its completion, the Auditorium became the largest government-owned assembly space for official functions. Perhaps most notably, the Auditorium hosted the signing of the treaty establishing NATO in 1949. Today, the GSA operates the space as a rentable event venue that is frequently used for weddings.

BCA performed a range of services to aid in the long-term stewardship of the Auditorium. BCA performed a thorough conditions assessment of all of the room’s features and a full finishes analysis focusing on the room’s ornamental plaster cornices and side-aisles. BCA also combined archival research and laboratory findings to identify the composition of historic building materials, most significantly the “Sphinxstone” brand cast-acoustical material used throughout the Auditorium’s walls and columns. Finally, BCA performed cleaning tests for removal of general soiling as well as iron staining from a pipe leak. Following the assessment and analysis of the historic materials, BCA prepared treatment and maintenance recommendations for the Auditorium and provided outline specifications for the recommended treatments.