Normally wall loads are measured in pounds per square foot.
EPS ratings are usually in PSI.
If you're REALLY worried about loading, they make higher strength versions.
Just talking about Foamular, as it's what I happen to easily be able to pull stuff up on. You can likely find similar products from other insulation vendors.
Baseline Foamular150: Compressive strength 15 PSI (basically (2160 PSF)
Foamular 250: Compressive strength 25 PSI (3600 PSF)
Foamular 400: Compressive strength 40 PSI (5760 PSF)
Foamular 600: Compressive strength: 60 PSI (8640 PSF)
Foamular 1000: Compressive strength: 100 PSI (14,400 PSF)
http://tinyurl.com/DeadLoadCalculations Page 5 for Dead Load calculations For this example, 1 floor and an unfinished basement on a concrete slab.
If you want to go CRAZY heavy construction, you're looking at about 430 PSF (
under the foundations, general load across even a HUGELY thick slab will be much less).
If you want to design in a safety factor multiply by 1.5 (covers things like adding solar panels and snow and other things to a roof). Now you're talking 645 PSF.
Even Foamular150 is still rated at 3x the load.
Pricing:
SOURCE:
https://www.insulation.supply. NOT intended as an accurate quote. Just for demonstrative purposes, so you can look yourself and see I'm not pulling numbers from someplace dark and poop-smelling. Shop around and you're likely to get a better price.
Foamular1000: $110-156
https://www.insulation.supply/product/foamular-1000-3-x-2-ft-x-8-ft-r-15-squared-edge-insulation-sheathing/ Foamular600: $46-54
https://www.insulation.supply/product/foamular-600-3-x-2-ft-x-8-ft-r-15-squared-edge-insulation-sheathing/ Foamular400: $44-53
https://www.insulation.supply/product/foamular-400-3-x-2-ft-x-8-ft-r-15-squared-edge-insulation-sheathing/ Foamular250: $21-25
https://www.insulation.supply/product/foamular-250-3-x-2-ft-x-8-ft-r-15-squared-edge-insulation-sheathing/ Foamular150: $23
https://www.menards.com/main/building-materials/insulation/insulation-panels/owens-corning-reg-foamular-reg-extruded-polystyrene-insulation-3-x-2-x-8-r-15/p-1444450499351-c-5779.htm So, for most single-story conventional home construction, something like Foamular150 would be fine.
However, with a negligible price difference, Foamular250 gives you an overkill safety margin.