Assuming I want to use standard concrete forms (not ICF blocks, or one-sided ICF) and want foam sheet insulation on the outside, what is the best way to do this? I think it would be best to add the foam to the inside of the concrete forms (and not try to glue on later), but not sure of the best way(s) to secure it to the concrete so I don't have to worry about it falling off in a few years.

I believe they make special form ties that can do this, but they are steel and I don't want thermal bridging so I'd like to remove the ties which is not possible with those ties.

I could put a few stainless screws or lags in it (from the inside, and not all the way through, to avoid thermal bridging), and assume that the head and threads will get stuck in the concrete, but that doesn't seem very good either (pull-out factor? Rust eventually?).

I see that Fox Blocks has made a tilt-up panel that may work (48" x 14 3/8" x 2.5"). It has plastic extrusions that embed in the concrete. I haven't priced that out yet and assume it will be more expensive than a standard 4'x8' sheet. Also since it's only 2.5" thick, it doesn't have much r-value. Although I plan on applying stucco to the exterior, it does have the plastic webs, you could use siding, etc. instead. I haven't found standard 4'x8' sheets that have embedded strips in them, although I haven't tried too hard.

The other problem is that I need to make sure the foam is pushed all the way to one side during pouring. I assume I could use some small foam blocks that sit between the sheets and form, but having a better way like plastic screws with stoppers at a certain depth would be better\easier. Ideally, I could find a plastic-type screw that both anchors and spaces but haven't found those yet.

Thoughts? Thanks

Why would you want to go through so much trouble? I have my own steel concrete forms and wanted to do the same thing but it's not worth the time or the hassle. I got about 150' linear feet of forms for a real good deal so as soon as price of steel goes up they will be going to the scrap yard where they belong. Also the foam will be very expensive and probably will be as close or even cost more than the actual ICF blocks themselves. In my case, I will need to hire a crew to set them and remove since they are so heavy. With the ICF you can do that yourself and as you install the ICF you can also run your rebars easily. Do you have your own forms and have you priced the foam insulation?

I have stucco applied directly to EPS foam and there are no problems with them separating. I'd expect the same for poured concrete. The thermal effect of even steel ties is pretty low.

Buy ICF's. I have two poured wall contractors as customers. We beat this idea around with them. The best solution is to buy a good ICF.