Hello. I am planning to build a new home this coming spring located in northwest Ohio. I have been researching the various techniques used for exterior walls, and have come here with some questions. I've narrowed my decision down to either a double stud wall (or a variation of the Larsen Truss) or a 6" or 8" flash and fill wall with the Mooney technique incorporated. During our winter season we can see extended temps in the low single digits and in the summer we can see extended periods in the 90's, so I want to build an efficient home for all seasons. The house will face south so we will also incorporate some passive solar techniques in building the house. Whether I use a double stud wall or Mooney wall, I plan to do the extra framing myself and not pay a contractor to do it (i am a union carpenter). We're contemplating using geothermal or radiant heat in the floor, but thats another question. I plan to use some sort of cultured stone on the exterior of the building. Questions: When building with a double stud wall using spray foam, like the one showed in building science.com's high r-value wall #10, is it wise to place a vapor barrier on the exterior side of the interior wall (as they show) if you spray the exterior wall with 2" of foam? For starters, it sure would be difficult to place the plastic on the exterior side of the interior wall, and secondly I thought I read somewhere that you did not want to incorporate 2 vapor barriers (the spray foam acting as one). This detail also shows densglass or fiberboard as the exterior sheathing. Why not use osb as exterior sheathing? When using a flash and fill wall, would 8" studs be a better option than 6", or just overkill? The Mooney technique seems like a very easy thing to do, however, if your going to spend the money to do a Mooney wall it almost seems like the same amount of wood could be used to erect a double stud wall.... In your opinions, are both of these techniques overkill? Would a 6" flash and fill wall be sufficient?