In order to complete your building thermal envelope, receive the same GBC / LEED points and gain conditioned space for free. Please contact a Structural Insulated Panel Manufacturer for your roofing needs. Connell

Seriously dude - wrong forum.

plus - all of you sips manufacturers need to come together like the ICF guys did and start something - cause right now sips are equivalent to wikepedia - an airplane navigated by passanger concensus. nuff said.

What do you recommend for insulating the roof / ceiling?

ICF's are a great product and I am glad to see discussions on insulating the slab. You now have a green, strong, energy efficient product on the walls and bottom however the 6 side of the equation is not complete. Don't you need product for the roof that will compliment all of the efforts put into the whole building envelope?

I-Joists for the rafters and spray foam. Gives you lots of flexibility in plumbing vents, wiring, and ductwork. Heat loss is very minimal if set at 24" O.C. and foamed well.

SIPs can definitely be an efficient, and cost effective, choice for a roof system in connection with ICF walls. How efficient, and cost effective will depend largely upon the design. They're ideal for vaulted ceilings, and for designs with conditioned attic space. They can also work very well for flat roof designs, depending upon the spans involved.