In 1924 the first iteration of a Student Union Building at the University of Idaho was a social club/restaurant/dance club/tea room called the Blue Bucket. Permeal French, the Dean of Women built the Blue Bucket as a social center for campus, and it quickly became the de facto University Center/Student Union even though it was privately owned.
In 1936 the University of Idaho purchased the Blue Bucket from Mrs. French, financing the purchase through the sale of bonds. The Blue Bucket was remodeled and an addition to the north was added, creating the university's first "Student Union Building". A University Bookstore was also placed in the addition's main floor and a ballroom was added on the second floor. Combined cost for the purchase, remodel and addition was a total of $75,000. The same 1936 bond issue also financed the construction of the Golf Course and Neale Stadium.
In 1949 the Student Union was expanded to the north to the edge of 7th Street. This expansion cost $676,231 and was financed through bond sales to be paid back through student fees.
In 1956 the SUB expanded again, creating a larger dining space on the main floor and a new main entry. The original Blue Bucket building was used as the Bookstore.
In 1961 the SUB expanded to the North and South. Seventh Street was closed and vacated on the north side to allow expansion in that direction. The original Blue Bucket building was torn down and replaced with an expanded facility. The new addition to the north includes a ballroom on the second floor, gallery space, a lounge and offices on the main floor. This expansion was financed with a federal loan to be repaid through fees and revenue.