A zoning overlay creates additional regulations for a specific area to address a site or area-specific need or objective. It modifies standard zoning regulations that are provided by the Zoning Code. Overlay districts are frequently used in zoning codes to preserve sensitive environmental features, preserve historic buildings, prevent development on unstable or vulnerable land features, or promote specific types of development, such as transit-oriented development. Like other zoning regulations, overlay districts can control building and urban design, permitted land use, density, and other factors.
The IZO has three Overlay zones in Chapter 5: the Flood Plain Overlay Zone, the Historic District Overlay Zone, and the Theater District Overlay Zone. These overlay zones guide important site, environmental, safety, compatibility, or design issues that require particular attention in project planning. When an overlay zone is applied to an area, any development within that area must comply with the underlying zoning and the overlay. Additionally, City Council expressed interest in creating a senior overlay zone over existing senior designated Mobile home parks.