I built an R2000 house in Canada 30 years ago, now its time for an update. I am intrigued by the use of 6 " EPS under cement floor on grade. (Will the house crush it?) Windows are hugely improved. HRV has also improved. Are their books out there on cutting edge principles in design and construction. I am also interested in choices in windows, appliances (12 V fridges) etc. I plan to be solar and grid tied, possibly with a battery back up. Exterior cladding choices especially in a seacoast canadian environment. A mostly one story house with a great room and a limited second floor.

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.

Posted By David R. Duchesne on 29 Jul 2017 04:23 PM
I built an R2000 house in Canada 30 years ago, now its time for an update. I am intrigued by the use of 6 " EPS under cement floor on grade. (Will the house crush it?) Windows are hugely improved. HRV has also improved. Are their books out there on cutting edge principles in design and construction. I am also interested in choices in windows, appliances (12 V fridges) etc. I plan to be solar and grid tied, possibly with a battery back up. Exterior cladding choices especially in a seacoast canadian environment. A mostly one story house with a great room and a limited second floor.

The PSI ratings of different foams aren't really the relevant parameters. The foam won't be crushed under a slab even with low density EPS but you don't want it to flex enough that it risks cracking the slab. Type-II (1.5lbs per cubic foot nominal density) is plenty-good enough for use under a 3-4" reinforced residential slab. Type-I (1lb density) would work too, but it's more fragile and lower-R. But there's no need to go for higher density than Type-II under a normal slab.

But under a stem wall FOOTING, (or the grade beam of that type of slab-on-grade foundation) carrying the full weight of the house it's important to do the engineering analysis, which usually calls for denser foam.

I dont prefer to read E-books, because I can't read properly, I always prefer to read hardcopy, and I recommend you to buy Passive House Details: Solutions for High-Performance Design and The Passivhaus Designer’s Manual: A Technical Guide to Low and Zero Energy Buildings, these both are a damn good book, you will learn many good things from this book, I bought both of them from verifiedcouponcode.com, there are varieties of books are available, if you wanna buy once check there.

I think the best book for passive solar house design is Edward Mazria’s “The Passive Solar Energy Book, Expanded Professional Edition”. Unfortunately, it is no longer in print but it can usually still be found in the used book markets. However, if you are just looking to accomplish a DIY passive solar house design, we have a suite of software for doing just that:

https://www.borstengineeringconstruction.com/Passive_Solar_Altitude_Angle_Calculator.html

https://www.borstengineeringconstruction.com/Passive_Solar_Roof_Overhang_Design_Calculator.html

https://www.borstengineeringconstruction.com/Passive_Solar_Fenestration_Exposure_Calculator.html

https://www.borstengineeringconstruction.com/Passive_Solar_Heat_Gain_Calculator.html

https://www.borstengineeringconstruction.com/Passive_Solar_Thermal_Mass_Performance_Calculator.html

And I should also add that Passive Solar House Design has nothing to do with Passivhaus Design, which is just one energy efficient house specification and frankly not a particularly good one IMHO. I would suggest getting energy efficient design guidance from sources such as Green Building Adviser rather than blindly going down the rigid and inflexible Passivhaus, LEEDS or other such pricey approaches. And do an integrated design that considers all aspects as opposed to doing a piecemeal design as is often unfortunately typically done.