Zone 5a, Southest Michigan. Based on the article Combining Exterior Rigid Foam With Fluffy Insulation, I’d like to have two 2″ layers of polyiso installed on the exterior of the roof sheathing when we re-roof our 1958 tri-level (along with fluffy insulation inside). We’ll likely do some additional envelope and mechanical improvements, but first priority is the roof.

I’m having trouble finding the right trades or expertise on this. Am I looking for a roofer, an insulation specialist, or a general builder/renovator?

Local builders and renovation contractors with a reputation for quality and/or green practices seem to be working only larger jobs (>$100k). Insulation contractors in the area seem to be all about spray foam. One particularly reputable roofer I talked with seemed somewhat open to working with rigid foam, but also made it clear that they’d be out of their area of expertise. A related concern is getting the details right. There’s a poorly implemented chase that’s been added on between two sections of roof (to carry a/c ducts in the unconditioned attic), and I want to get both the aesthetics and the continuous air barrier right at the eaves. I want to do this right, but I haven’t been able to connect with the right expertise yet. Advice?