Seems like a simple question but its not. Complicated by circumstances that you are not yet perhaps even aware of. Best answer is not to ask here - you really need a demo or construction professional to come out and look at the site and get you farther along in the process.
Site situation, zoning, nearby buildings are all issues / go to the source and get a straight answer.
Barlow and Birdsall Group
Keller Williams Realty Center City