Hi, I just saw this post and wanted to say that here in Ca. it is not the amount of room you have for a shed but all of the laws governing the building of one including any homeowners associations rules or subdivision rules.
We have to be 15 feet away from side and back property lines and no buildings on the front property line. Then if we build any larger than a 10X12 we need a permit (not cheap) and then it has to be inspected. That would include any electrical, plumbing and of course..foundations etc. They always find something wrong and charge for more inspections etc.
REAL PAIN IN THE ARSEY so we usually stay with a 10X12.
I hope you do not have all of these rules and regulations where you live.
Lorraine