The Z. T. Gerganoff records represent a small portion of the firms output. In 1983, the firm's offices at 206 N. Washington in Ypsilanti were sold, and its records offered to the Michigan Historical Collections. Many of the records had been scattered or destroyed over the years, due to the firm's need for space and its practice of returning records to clients after the completion of a job.
Of the records remaining in the office in July 1983, the Michigan Historical Collections accessioned architectural drawings and specifications relating to churches, service stations and auto dealerships, the Washtenaw County Building, Washtenaw Country Club clubhouse, and a few other buildings, along with miscellaneous renderings of residences, apartment buildings, and businesses. Left at the office to be destroyed were drawings of other county courthouses and schools. Drawings of many Ypsilanti buildings had been donated to the Ypsilanti Historical Museum, and drawings of Eastern Michigan University buildings had been turned over to the University.
This record group consists of architectural drawings for 56 of Gerganoff's projects and a smaller series of specifications for two projects. The architectural drawings series is composed of three subseries: churches; service stations and auto dealerships; and other buildings. Within each subseries, buildings are arranged by location and then chronologically (by job number), with undated and miscellaneous material at the end.
Ralph Stephens Gerganoff graduated from the University of Michigan in 1917 with a bachelor's degree in architecture. After practicing in Wisconsin and Detroit, he opened an office in Ypsilanti around 1925. Over the next 40 years, his firm was responsible for a great proportion of the architectural work in Ypsilanti, including most of the Ypsilanti public school buildings, at least 12 buildings at Eastern Michigan University, Beyer Memorial Hospital, and a number of residences, churches, apartment buildings, and businesses. In Ann Arbor, the firm designed the Washtenaw County Building (1955), the Ypsi-Ann Building (later known as the Wolverine Building), Kingsley Apartments, and other buildings. St. Clement Ohridski Macedono Bulgarian Eastern Orthodox Church in Dearborn is one of the firm's best known projects. Schools, churches, county courthouses, residences, and service stations were among the firm's specialties. An album of the firm's work before 1952 is found in the book Architectural Work and Designs by R.S. Gerganoff, in the printed collection.
After R.S. Gerganoff's death in 1966, Stoyan T. Gerganoff took over the firm. He in turn was succeeded in 1980 by Zdravko T. Gerganoff, R.S. Gerganoff's nephew, who had worked for R.S. Gerganoff during the 1950's and who during the 1960s had opened his own architectural firm.