Studies, analyzes, and compares three methods of seismic reinforcement: Uniform Building Code (UBC), ABK, and Base Isolation, to determine which would upgrade the City and County Building in Salt Lake City (built prior to seismic design considerations) while retaining the greatest amount of historic fabric. The first two approaches necessitate complete removal of architectural finishes with the resultant replacement of an old veneer onto a new frame. Base Isolation, on the other hand, takes the approach of separation through which the building is isolated from ground motion by placing the building on shock absorbers, rubber pads with steel plates between, at foundation level. This method was found to be more advantageous. While the required life safety could be provided, damage would appear to be less. The system selected is based on the original New Zealand patent and has been used for contemporary construction. This project, which is currently under construction, is the first example of the application of base isolation to a historic building.