Every building hereafter erected, reconstructed, converted, moved or structurally altered shall be located on a lot or lot of record and in no case shall there be more than one principal building on a lot unless otherwise provided. More than one principal building of a single permitted use may be located upon a lot or tract in the following instances if recommended by the Planning and Zoning Commission and approved by the City Council.
1. Institutional buildings.
2. Public or semi-public buildings.
3. Multiple-family dwellings.
4. Commercial or industrial buildings.
5. Home for the aged.
6. Agricultural buildings.
7. Planned Unit Developments.