It's a house, but I think that little area on the side is so his wife can do work at home for their business.
From what I hear (and it could be wrong), they ran out of money to finish stuff on the inside. He already owned that piece of land and has a building in the back where he parks his trucks for his business. I live right there in the sub-division next to it. He used to live in here too, had a couple of houses in here, but sold them a couple of years ago.