We knew we didn’t want to go back to fiberglass (or whatever they use now) batts for insulation, and after much on-line research, and chit-chatting amongst ourselves, we went with Soy Therm 50.
Soy Therm 50 spray-foam insulation is innovative, environmentally friendly and made with Soyol, USSC’s patented, soy-based polyol technology. It is an open-celled, water-blown, rigid polyurethane insulating foam that contains no ozone-depleting chemicals, VOCs, formaldehyde or asbestos. It expands upon application to fill all voids and cracks, and can save significantly on heating and cooling costs. At a density of 1/2 lb. per cu. ft., this is an excellent rigid foam insulation product for commercial and residential use.
…says the United Soybean Board web page….
And this is what it looks like part way through the process. You may be able to tell that the foam is applied against the outside of the house/roof, so everything—at least in new construction—inside of the outside walls would be “interior” relative to the insulation. And, bonus!, this means the house is much better sealed, especially against insects and other critter infestations. Even though we’re just able to have this on part of the upstairs, I think it’ll make a huge difference. Yes, we’re paying more, but I think we’ll be happier with our living situation (yea!, more storage! and more storage that’s insulated!).