I am building a passive solar home and have question about insulating and air sealing a slab on-grade foundation. Do you know of any schematic drawings that illustrates ways to air seal and insulate a slab? I am living in extreme northern Maine, (~8300 HDD climate). I think I need >R-40. No number crunching presently. I really like GO Logic's process and think it makes complete sense but it must be a pricey application. 6" of EPS foam extending ~18" beyond the edges of the slab, ICF footings, a sealed plastic continuous air barrier spanning underneath the slab up the foundation and sealed to the interior wall panels. It appears from the pictures that an additional 2" pink styrofoam is topping that before the concrete is poured. http://www.gologichomes.com/blog/2009/09/foundation-vapor-barrier-installed/ Any thoughts/suggestions?

Try here although it doesn't show the vertical insulation that would also be used outside of the foundation.

I think the best approach is to contact the contractor who built the house directly and ask him for the details. He may be happy to share,or he may charge you for the information, but either way he's done it and knows the answers you're looking for. There is an element of outreach, of spreading the word among many progressive builders and especially Passive House proponents - we are concerned that we all need to change the way we build houses and we realize that we need to educate others in the correct ways to achieve these results, whether or not we'll profit from it ourselves.

The wing insulation is to protect from frost heaving the footings, and the amount required is climate-specific.

Use of XPS (pink, blue, green, whaddevah) is preferred by folks who install radiant heating in the slabs due to it's superior ability for retaining the staples that hold the tubing down prior to the pour. It's usually30-50% more expensive for equivalent-R EPS. But all almost XPS manufactured in N. America is blown with HFC134a, which has about 1400x the greenhouse gas potential of CO2. By contrast EPS is blown with pentane, with only 7x CO2 potential. Unless there's an over-riding factor, it's cheaper/better/greener to go with EPS.

FWIW: XPS manufactured in Europe is blown with CO2 (which surprisingly has the same greenhouse potential as CO2 :-) ). But it also has a lower R per thickness- R4.2 per inch for 1.5lb density, the same as Type-II EPS. But it is more rugged in handling than EPS, and has the same tubing-staple retention as 1.5lb goods blown with HFCs.

Pouring the stem wall on footings at the design frost depth in an insulated concrete form (ICF) uses about the same amount of EPS as wing-insulation, and can be a bit less labor intensive than wing insulation on a shallower foundation (unless you're digging the foundation by hand.) When insulating under a footing in a frost-protected shallow foundation it sometimes takes 2.5lb EPS (aka "Type XIV") to bear the weight of the house, but this is a detail to be worked out by the architects & engineers doing the design.