It all will depend on the location of the property, the song, and the historic designation of the building and the neighborhood, all combined. Also, the floor area ratio, or percentage of occupied space by enclosed structures in your property. As per your description, you will need a permit to do what you plan to do. You will need a permit set of plans, showing how your future garage will relate to the house, and a new plat drawing and survey of the house, to show the improvements to the property. There are code issues frequently overlooked when people transform carport into garages, the most important of them is the co2 buildup in garages an its risk of poisoning the occupants of the new house. Hope this helps. Fell free to email me at odcstudio at aol dot com.