The term "contributing" does not refer to the fact that a certain percentage of the building in an historic district need to be over 50 old. It is merely a way of inventorying the building stock when the surveys for the historic district were completed. To be contributing (and protected) in the historic district, it has to be 50 years old and retain its achitectural integrity (i.e. it hasn't been remodeled and lost its original architectural style). You have to remember that the Zoning Overlay applies to the entire neighborhood from the Fuller Warren overpass, along the railroad tracks to the North and West and to the Fishweir creek area. That encompasses all of the historic district proper and the surrounding neightborhoods. There are contributing structures and non-contributing structures within the historic district. There are no contributing structures outside of the historic district. Some buildings were carved out of the historic district proper, such as the property at issue here, because they were associated with Riverside Hospital or St. Vincent's Hospital. The distinction is retained in the overlay because of a recognition that historic retail (such as Five Points and St. Johns shops) don't have the land to provide additional parking although they are already commercial. No one wants to kill what's already there. But the intent of the overlay was to make sure that new projects provide at least some parking (hence the 75% reduction from normal parking requirements.