I live in southern Minnesota, climate zone 6. My house is about 6 years old w/exterior foam insulation (R-5) on the poured foundation walls. It's a lookout w/daylight windows.
I'm working on a plan to finish the basement. Looking around online, I can't find a clear, recommended direction for finishing the interior walls if the exterior is already insulated. City handout doesn't really address it, and I haven't had time to call the city inspector yet.
I'm thinking of using 1" rigid foam board on the inside, sealing the seams with tape and foam, and then framing with 2x4s, but using no other insulation or vapor barriers. It appears this would give the basement an R-10 insulation factor.
Should I consider something different? Of course, the city will have to approve any plans, but I wouldn't mind some thoughts on where to start in my planning.
Start with a wider top plate that touches the sill plate on top of the concrete.
Fire stop between the wall and the floor system is required. We can use drywall, 1/2 plywood or OSB, but there might be local requirement.
We often just use a 2x4 or 2x6 between the top plate and the sill plate.
Level down to the floors and the perimeter of the basement is lined out and is just as square as the house upstairs.
If you do that top plate work first and then the foam you have saved some work later.
Don't forget sill gasket at the floor or anywhere wood touches concrete.