Thanks to all contributors for the wealth of information I've already obtained from existing threads.
My wife and I are getting ready to build a house near Cody, Wyoming (7800 HDD, but quite dry). We really want an efficient house to minimize future energy needs.
We own a .70 acre (138Wx231L) north facing lot that is flat; we also own the identical-sized adjoining lot to the east. Houses on these lots must face north toward the street. The ground has not been farmed for years and is very hard and dry. The house behind the lots is single story, and the lots runs N and S, so we're counting on maximizing our solar options, to the point of involving a solar design specialist to make sure we don't mess anything up.
We have a good amount of contruction experience, including assisting on ICF, stick-frame, and SIP builds. We also have access to equipment and (relatively) good and cheap labor. We did most of the work to build our current 3,300 sqft stick-built house. However, at that point I was not enlightened to the concepts of green building and sustainability, so the house's efficiency and energy features stink.
At this point, we are strongly considering a gambrel barn house (see barnplans.com) with a simple retangular (32'x40'=144' perimeter) foundation and framing plan. The house would have an unfinished 8' basement (mainly for storage), 8' or 9' main floor, and second floor. I'd love to cut back on the size, but I'm having to address a mother-in-law accommodation issue (unless you have non-violent solutions, please don't ask).
For the basement, I'm looking at Nudura or FoxBlocks 6" ICFs (no info yet on 8"/10"/12"). I can DIY for $7.00/sqft of wall or contract it out for $10.00/sqft. We're planning for 3" EPS under the basement floor; but, we're not really considering PEX in the slab. We'll probably have the rear (S) of the basement be walk out by only sinking the basement 4' and using porches and new dirt that will slope away from the front and sides of the house. On the south side, we hope to incorporate extensive passive solar into the exposed basement with a optimally designed shed porch roof.
For the main floor, I'm considering 1) taking the ICFs on up, 2) using 2x6" 24" oc (advanced framing techniques), wet-spray cellulose, and (as needed) rigid iso on the exterior, or 3) using double stud 2x4 offset walls 24" oc, wet-spray cellulose, and, perhaps, exterior sheathing. My research shows SIPs to seem expensive compared to the other options. The house exterior will probably be steel or cement board siding.
For the second floor, the gambrel truss design will probably need to be insulated with spray foam to achieve a balanced R-value relative to the rest of the house. The roof will be a steel roof to facilitate rainwater catchment.
I will likely utilize the roof for solar collectors for radiant heating and water heating systems incorporating a basement-level heat exchanger and boiler system with radiant heating in the living areas. We'll also have a wood stove available.
The garage will be detached, but that's for another post and another day.
I guess I'm looking for comments and suggestions that will help make this a more successful project. In particular, for the main floor, how will my known ICF cost ($7.00) compare to the other options (2x6" advanced and double stud)? Is the gambrel barn design a reasonable approach? Also, what am I missing?
Some Visual Helps
