Thanks for the reply! To make sure I understand your last point, do you mean put a layer of xps under the bottom of the studwall (between the treated lumber and concrete)?

Also, is there a scenario where you would recommend a moisture barrier? I've been trying to research this, and it seems most resources strongly advise against them.

do you mean put a layer of xps under the bottom of the studwall (between the treated lumber and concrete)?

Yes.

I avoid lumber, treated or otherwise, in basements. It's simpler, easier and safer to use light-gauge metal.

a moisture barrier

Assuming you mean against the interior foundation wall. This was an older system that sometimes still shows up. I did it in the '90s. The idea was to move water condensing on the inside of the wall down the poly and under the base into the interior where it would dissipate. Better to stop the water condensing in the first place.

We recently finished our basement and had several cracks filled with injected material. Can’t recall, need to check, epoxy? We did XPS boards with glue/tape. Framing was about 1-2” in front of that. I read to use composite 2x4 on the floor for sill plate with the treated on top of that. I would have done that but we ended up just with the pressure treated.

We did spray foam all above ground exterior walls and rim joists (we have English basement). And Roxul for the rest. No other vapor barrier.

We also did soundproofing in ceiling.

Will see how it goes!

we used foam panels with built-in plastic “studs”, the panels were glued to the existing block walls. The studs are for attaching drywall, and the panels have hidden vertical & horizontal chases to run electric.

https://www.insofast.com

Basement Foam Board Insulation: Pros and Cons.

https://www.heating-air-conditioning.net/

Foam board insulation are rigid panels of insulation that can be used to insulate any part of your home from the top to the bottom.

The material can be made from polystyrene, polyisocyanurate, or polyurethane.

Pros:

Some rigid foam products are water resistant that can help limit moisture buildup and mildew-growth.

If foam board is installed properly, the rigid material can create an air barrier.

Unlike traditional insulation, like fiberglass and cellulose, some foam board materials don’t need to be maintained or replaced over time.

Cons:

Joints between sheets and boards if not taped properly will not prevent air flow.

The air bubbles inside expanded polystyrene boards stop heat transfer, but can accumulate moisture which will make it ineffective.

The foam boards must be cut exactly to fit the area where it will be installed. If the boards are not cut properly, then air leakage could occur.

I did my basement walls a couple of ways. In utility areas and places I didn't need room for pipes or wires I put up 2" of XPS and then tapconned moisture resistant gypsum board or osb over that. Where I needed utility space I put up 2x4 framing in front with a treated plate and then added regular gypsum board. I read that it isn't a good idea to have fiberglass on exterior basement walls. Where walls weren't exposed to soil I added fiberglass insulation. It all worked out very nicely.

Above grade or below, moisture sensitive insulation is not advisable unless it is on top of sufficient non-sensitive insulation against the interior wall of the foundation.

Source: Building America Solution Center

There are five mechanisms for water entry into the basement insulation system. During summertime, air from the interior and under the slab contacts the colder foundation and condenses into water, feeding the mould spores what they crave to thrive.