I have built a wood basement under a new home and I’m trying to decide on how to insulate and vapor barrier it. I live in ND the weather can get to 40 below to 100 above. What I have done is poured concrete foundation footing 4’ to the bottom from grade. I built a 2x6 wood wall on it with green treat. The outside I put foundation coating on and then wrapped it in poly. The floor is also wood 2x8 1 foot apart placed on the inside of the top of the footings with a vapor barrier on the sand/ground. Now I thought that I would insulate the walls with fiberglass kraftfaced to the inside and duct my heat/ac down two walls on each end under the floor. Any suggestions or thoughts to my insulating and vapor barrier?

I'd worry about pressure on the 2x6 wall.
What'd you use for the outer sheathing of the wall?
Is all of this stuff rated for ground contact/foundation grade?
How are the studs fastened to the top and bottom plates?
And how have you back-filled?

Building inspector said I had to use green treat the outside is 1/2” below grade ply. Yes everything is ground contact foundation grade. The studs are nailed to the plates one foot on center with each floor joist matched to them. The basement is a daylight basement so it is only back filled to 4’.

Building inspector said I had to use green treat the outside is 1/2” below grade ply. Yes everything is ground contact foundation grade. The studs are nailed to the plates one foot on center with each floor joist matched to them. The basement is a daylight basement so it is only back filled to 4’.

Building inspector said I had to use green treat the outside is 1/2” below grade ply. Yes everything is ground contact foundation grade. The studs are nailed to the plates one foot on center with each floor joist matched to them. The basement is a daylight basement so it is only back filled to 4’.

Building inspector said I had to use green treat the outside is 1/2” below grade ply. Yes everything is ground contact foundation grade. The studs are nailed to the plates one foot on center with each floor joist matched to them. The basement is a daylight basement so it is only back filled to 4’.

Thank you. Anyone else have any advice?

Okay. So it's not a full burial basement. So 2x6 and 1/2" are probably sufficient (most places I see recommend 2x8 minimum and 5/8" or 3/4").
If you've already put on some sort of fluid applied membrane and a vapor barrier, all you really need outside is a dimple mat or similar draininage membrane down to a french drain or drainage plane.

Inside, would recommend caulking the stud bays.
Go mineral wool instead of fiberglass.

Mineral wool is hydrophobic.
Fiberglass becomes a useless lint ball when wet.

Air permeable insulation like batts requires good air barriers on all sides. When the exterior side is in contact with the ground or has an exterior side vapor barrier it can't dry toward the exterior, and must dry toward the exterior. This is a problematic assembly, but not impossible.

A kraft facer cannot be adequately detailed as an air barrier, but wallboard can. Painting the wallboard with half-perm paint (aka "vapor barrier latex") will limit the amount of moisture accumulation, but also slows the drying rate. Air tightness is critical to keep the exterior sheathing and fiber insulation from getting wet. Getting it sufficiently air tight to begin with is a painstaking process. Keeping it air tight for the duration isn't too likely.

As much as I hate the stuff, installing 2" of closed cell spray polyurethane against the sheathing and installing R15 fiberglass or rock wool (or kraft faced R13s) in the remaining 3.5" will put sufficient air-impermeable R-value between the cold exterior and the fiber insulation to mitigate against moisture accumulation over the winter. It's still good to make the wallboard as air tight as possible, but minor air leakage won't create a chronic problem. Closed cell foam blown with HFCs runs about R6/inch and a buck per square foot per inch of depth. The HFC blowing agent (usually HFC245fa) has been banned under the Kigali Amendment to the Montreal Protocol, due to it's extreme greenhouse potential (about 1000x CO2), but it has not been adopted in the US. There are closed cell foams blown with HFO1234ze, which is far more benign and slightly higher performance at about R7/inch, but it's more expensive at about $1.25-1.40 per board-foot. Either would run about 0.5-0.7 perms, which is open enough to keep the wood from getting saturated over time, but sufficiently vapor tight to not take on significant moisture into the foam itself. It's expensive, and it's high R/inch is somewhat wasted when thermally bridged by studs, but it removes most of the risk of signficant moisture/frost accumulation in the air permeable fiber insulation.

I would like to thank everyone for there input and giving me a direction to go.
Sincerely,
Nick
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