Allen,
I don't know where this home is located...however here is the situation. The building can not count towards
the square footage of the home. As long as you are alright with that.....the only question I have is how did they get
an electrical permit without a building permit? In California you have to have one to get the other.
Bring in an inspector to look over everything to make sure it is built soundly, and no major problems. You don't want any issues down the road from faulty building. Also, when you sell, one day, the same thing will apply....you also can not count the building square footage into the total for the home.
Last comment would be just to make sure there are no city issues with having a non permitted dwelling on the property. I believe you mentioned it was for storage...so should not be an issue.
