Jim McElwain is a regular at his local hardware store. The tech salesman started building a tiny home ten years ago as a DIY hobby on the weekends, and has put it together alone, piece by piece. Each time he needs more wood or drywall, he returns to the store. And if he doesn't know how to do something — like assemble roof panels or put up drywall— he searches for a YouTube tutorial. As of this spring, his 400-square-foot space in rural Ohio is fully furnished with a working kitchen, shower,