Quote Originally Posted by electrofelon View Post
Not sure which the OP was planning, or if he has room for a ground mount, but I would go ground mount if possible. Probably will be able to get more ideal angles and better production than the roof, unless the roof gets you above obstructions. Also one can "homebrew" ground mount mounting structures (assuming you want to invest some time to save some money) much easier than roof mount systems. Lastly, if you need another structure anyway, like a carpart or wood shed, it can make it really cost effective.
Ground mounting is generally more expensive than roof mounting. You might be able to "homebrew" a ground mounting system but you might not, depending on where you are. Some AHJs require a PE stamped structural drawing or letter for a ground mounted PV system.

One advantage, however, to a ground mounted system is that in general rapid shutdown rules do not apply.