Protecting slab insulation?

[VietGnome]

Concrete guys are in putting up the last of the insulation around the slab.

The plans call for it to end below grade, however with the 2' sheets they come right above grade, and up the 8" knee wall a few inches below the framing.

I'm not upset about it because more insulation, but now I need to figure out how to finish it.

The knee wall bows out in a few places anyways, so I was planning to flash the entire bottom perimeter, put J-trim ontop, and side up from there.

As far as protecting the foam, what options do you all recommend? I've read about parging it, and cement board. Curious on opinions either way. Id prefer to keep it cheap as possible, but I'm also supportive of spending a little extra to "overdo it"

Edit: photos

 

[jack stand]

This is probably a little extreme compared to your plans, but I'd find a used or 2nds rigid foam supplier and put matching (2")? foam on all of the walls especially if you plan on insulating anyway.
Locally I can buy 2" foil faced 4x8 foam for under $25/sheet from the Amish. Exterior foam is really the best system that they use these days.
It would require mailers on the foam or set on the sheathing and foam sheets in-between.
You'd end up with a exterior flat and continuous right to the grade that I'd finish with a PT 2x8 at the grade, covering the foam from the sun and damage and flash the top to run your siding onto.

 

[VietGnome]

This is probably a little extreme compared to your plans, but I'd find a used or 2nds rigid foam supplier and put matching (2")? foam on all of the walls especially if you plan on insulating anyway.
Locally I can buy 2" foil faced 4x8 foam for under $25/sheet from the Amish. Exterior foam is really the best system that they use these days.
It would require mailers on the foam or set on the sheathing and foam sheets in-between.
You'd end up with a exterior flat and continuous right to the grade that I'd finish with a PT 2x8 at the grade, covering the foam from the sun and damage and flash the top to run your siding onto.

Ill look around but I think that might be out of my price range. 2" XPS here is savagely priced. I almost didnt do full under slab insulation.

Im debating getting Coil stock and having one continuing piece of flashing from house down the side to grade.

I worry about stucco or parge not staying on. And cement board is thick and unsure how I would adhere it.

 

[jack stand]

Coil will "oil can" terribly in the dimensions you need.
What's your siding (above) going to be?
Edit: I wonder if there's a foundation "tar" that's not aggressive with the foam?
Painting things like this down low dark kinda makes it go away, at least at a glance.
Then there's low foundation shrubbery!

 

[kj_mustang]

Galvanized steel mesh attached with long washered ramset type pins. Stucco it or mortar screed it and then apply stone veneer. Z flashing over the top edge then your siding.

 

[Fav Onefour]

I have the same insulation setup around a home foundation. I scuffed the foam and applied stucco. It was a dumb idea. I had areas that flaked off pretty quickly with light contact while finishing up landscaping. If you don't reapply the stucco right away, the foam breaks down and won't hold new stucco.

Go with the steel mesh method @kj_mustang , is suggesting. Use good Z flashing and gap your siding correctly.