The purpose of this post is to correct a huge oversight on my part and I want to thank poster "Mario in VT" for bringing it to our attention....we never shared our decision re: SIPs vs. ICFs! Oops. It's a minor decision, really. It's only our entire wall system (!) So sorry for that omission. Apparently I've been much more worried about critical issues like whether to purchase a refrigerator with a top or bottom freezer.
Anyway, we have decided to go with SIPs. We actually really wanted a full ICF house. There has been some debate about whether ICFs truly offer a tighter envelope over SIPs. I think what attracted us to ICFs is that in addition to the (potentially slight) advantage in terms of insulating power over SIPs, we also liked the idea of not using any wood. Over time, that wood will begin to decay and concrete is here to stay. It also seemed like a good way to avoid using any more natural resources. Then again, producing concrete is very taxing to the environment. So we explored using a large percentage of fly ash, a waste product that is harmful when released into the atmosphere. Using fly ash also decreases the amount of damaging-to-produce concrete. Anyway, we were leaning towards ICFs although it certainly wasn't an emotionally wrenching decision to choose SIPs instead. We basically want the tightest building envelope that our budget will buy. And once we received the bids back (two from ICF companies and two from SIP companies), it became obvious that SIPs were more budget friendly. I will say that there wasn't a huge difference. But the difference was big enough that we couldn't justify choosing ICFs over SIPs. However, we will be using ICFs from Vermont ICF for our basement.
We are buying our SIPs from Panel Pros out of Keene, New Hampshire. These will be 6.5" Insulspan panels, R-26. So far, Panel Pros has been great to work with. Our total panel package came to around $27,000 without installation. This price includes structural design and delivery. With Al's help, we are going to install them ourselves. Panel Pros also quoted us on a SIP roof but because of cost constraints, we are going to go with a traditional truss roof and blown-in insulation.
Here is a link to Insulspan's website that has some great, basic information on SIPs. Fine Homebuilding has a nice overview article, too. This is the most basic diagram I could find of a SIP. Also, check out this ridiculous YouTube video (the music is classic) of the guys at Insulspan putting up a SIP building. Okay, and this one is just weird. It's called: Insulspan SIPs & ICFs used to build "The Moon." I don't get it. And yet I watched it. I really have too much time on my hands.