I know this is really stretching the subject off topic, but let me ask anyway. How do I insulate the ductwork inside the stud bays? I used to work at a summer job with an HVAC contractor and we did a lot of application of insulation to the interior of square ductwork. Is that what should be done here? Since all of my ducts will be in conditioned space, do I even need to insulate them at all?

Mark, how are you palnning on doing yours?

BTW, thanks for the good idea on bracing Jim. It seems to me that since I am using an ICF exterior and probably panels for the roof, I will have no (or very few) interior loadbearing walls. Cutting through the top plate of my interior walls shouldn't concern me that much anyway, right? As long as I can brace them on the ceiling joist, I should be okay.

I wish all you guys lived next door so we could sit a jaw about this stuff without having to type and check spelling.

JKC

JKC

>Weakening the wall by cutting the top plate is eliminated by securing the top plate on each side of the duct run to the ceiling joists!<

That's what I did, using a ring-shank nail to toe nail from each side.  I'd still rather have a double 2x plate here in seismic D country.  (Code called for galvanized ring shanks for one area in my construction and the smallest amount I could buy was enough to do the whole building.  A couple times I had to use a sawzall  with a metal cutting blade in order to change some framing.)

I don't live in a climate where insulating duct work is much of an issue.  The only area where it might be a concern for me is the incoming cold air for the HRV.  It comes directly into conditioned space, so it would be possible for warm interior air to condense on the ouside of that 6" pipe.  Since the purpose of the HRV is to reduce humidity inside my tight construction with an unvented roof, if I do get condensation that means that my design has failed and I'll look to fixing the design before using insulation as a band-aid.

I tend to think of any condensation as a design failure.  Well, maybe a little on the windows when you're boiling lutefisk and it's snowing.  Uffda, that sounds good.

Mark

Ducts in conditioned spaces do not require insulation!

As I said earlier I wouldn't build on a crawl or a basement unless on a walkout lot. To many reasons to mention!

This series of posting is what I like to see. Go back and read the wide range this one has taken. This is truly outside of your box thinking. "If your not thinking outside of your box, why are you thinking?". Eldon Howe

I definetely agree with Eldon.  As a prospective DIYer in southeastern Virginia a lot of the items in this discussion (slab vs. crawl, radiant and geothermal tie ins, SIPs roofing, etc) will be useful as I plan and begin talks with an architect.

Another kudos to the pros for sharing their insight!

Keep in mind that developing a plan with a professional designer or architect sometimes may seem frustrating in the beginning. The issue is whether they have experience with the technology of Insulating Concrete Forms or whether you will be paying for their learning curve.