Insulating a cathedral ceiling in a dining room addition – GreenBuildingAdvisor

I’m trying to decide what type of insulation i should use in a cathedral ceiling – new build – and if it needs to be vented.

I have a dining room addition under construction and i have to make some quick decisions: 1) Framers are asking: Do i want them to fur the ceiling rafters down 3 inches for batt insulation 2) Roofer (scheduled for saturday/monday) is asking: Do i want a ridge vent.

I believe the code requirement is R-38 in the zone i’m in. (NC – i think its zone 3)

I have an insulation company (who does all types – open/closed spray and batt, etc) coming tomorrow to give me a quote and discuss options. I’m always afraid they’re just going to point me to whatever they make the most profit on.

My goal isnt so much to save money but to just get the best install when it comes to longevity, protecting the decking from rot/mold, and being efficient.

From my own research, it seems like closed cell spray foam (or maybe the first several inches closed cell and the remainder open cell or some other insulation) might be the best option (though not the cheapest). And this option would mean an unvented cathedral roof. And then probably the cheapest option being batt insulation with ridge and soffit vents. 

If this were your house, what method would you use and why?