Structures / Old San Francisco Mint
- United States Treasury Department – Office of the Supervising Architect of the Treasury
- Alfred Bult Mullett
The Old San Francisco Mint is a three-story brick masonry and stone-clad bearing and shear wall structure that measures approximately 220.5 feet in the north-south direction by 165 feet in the east-west direction. There is a courtyard in the center that measures about 102.5 feet north-south by 43 feet east-west. The building sits on a massive mat-type foundation of unreinforced concrete that is approximately 4 to 4.5 feet thick below the basement level. The average building height from ground level to the roof is 52.5 feet. The first and second floors are constructed of wrought iron beams supported on the masonry walls and cast-iron columns. The floors consist of shallow brick arches with a concrete rubble fill on top spanning between the beams. The floors are typically finished with stone pavers or hardwood floor. The attic floor system is made of shallow, corrugate iron arches with a concrete rubble fill on top. The roof framing includes wrought iron beams and trusses with stacked timber joists and straight timber sheathing, creating the roof diaphragm.
There are two large, main chimney stacks on the roof that taper from 12 feet square at the base to 11.5 foot square at the top. These chimneys were originally extended 69 feet above the gable roof. The top 25 feet of both main chimney stacks was clad with ornate cast iron. Each chimney has a central flue and four corner flues.
The Mint was constructed between 1869 and 1874 and immediately proved to be an important hub and resource for the community, which frequented the building to turn gold into coins. The newspapers at this time highlighted two of Alfred Bult Mullett’s original program design objectives: design and build a structure that was both “Fire Proof” and “Earthquake Proof”. The Mint was put to the test in the 1906 San Francisco earthquake. The system of seismic resistant elements and anchorage details that were installed as part of the original construction contributed to the relatively little damage the building sustained during the earthquake. Also, despite being in the “heart” of the fires that ensued after the quake, the workers were able to prevent the flames from reaching the only flammable surface: the roof. In the aftermath, people flocked to the Mint as a safe-haven and many camped out front of the building, entrusting its seismic performance.
- United National Register of Historic Places (1966)
- National Historic Landmark (1961)
- California Historic Land Mark (1974)
- San Francisco Designated Landmark (2003)
- The building survived the 1906 San Francisco earthquake and fire whereas all the other buildings in that area of San Francisco were destroyed.
- The building has never been retrofitted, but the courtyard was infilled at the first level in the mid 1970’s.
- The top 25 feet of the chimneys, including the ornate cast-iron, was removed after sustaining damage in the 1906 San Francisco earthquake.