We are very glad we took that route. The walls are R50 (2.5” rigid insulation on both sides of an 8” concrete wall, although forms are available for different thicknesses of concrete)...before the earth-sheltering backfill. You have never been in a quieter home and it’s bullet proof, an increasingly valuable characteristic. :{)
The cost of the forms is tied to the oil prices and is costlier than wood framing at the best of markets.
Wow. I’ve always known it was more expensive and thought the extra cost was worth the benefits. Now I’ll probably go back to buying ICF magazines and looking at it all over again. Very nice. Love the pics, too.