Usually these kinds of small projects are pay in advance/pay as it goes right? You have to cut the builder a check for materials and a good portion of the labor before the job even starts right?
I'd guess the issue is that the builder has nothing to lose. If you try to force him to fix stuff he can just walk and say "sue me". Then you have the burden of proving he messed up in court and getting money out of him all the while your building sits unfinished. He can say it was the homeowners fault for telling him to do things different. Probably a thousand ways a dirtbag builder can get out of any responsibility here.
Then you have to find a competent builder to fix all the stuff.
That's a whole nother issue in itself- How much does a good builder charge to fix what the other screwed up plus finish it?
As a machinist, when I get those kinds of projects where someone else has already done their best to screw something up it can get real time consuming ($$$$) to re-do the work to make it right.
If I were in the OP's shoes I would do my darndest to educate myself about the right way to build my building and try as hard as I could to guide/steer/massage the building back on coarse to a decent finished product.
I hesitate to suggest this, but the OP could reach out to his county's planning commission and ask for a voluntary inspection. Get an inspector to walk through the building to check the progress so far. I think if it were handled real carefully so everyone was on the same page maybe the inspector could suggest ways to bring the structure into compliance and the builder might be more responsive to the inspector if the OP isn't getting any traction. That could totally blow up in the OP's face and the builder could take it as an attack from the OP.
