Rigid Foam and Batt Insulation Application
I’m in the process of adding a geo dome tent on my property. I am building a deck that the dome will sit on, so that means some of the deck will be planked out but the portion of the deck that the dome sits on will have plywood sheathing on it. I would like to add insulation underneath that portion, as the dome will have heating and air con. ( I am in southwest Ohio so we have all the weather!)
My plan was to use 2×4 blocks attached to the joists (2×10) to help hold up a layer of 1″ rigid foam. I planned on using spray foam to seal the sides and seams of the rigid foam.
Then i plan on filling the remaining space with roll insulation. (I’m currently looking at R25 compressed 1″ to fit in that space.
The reasoning behind this method is….
1. rigid foam will create a layer that will hold the roll insulation while also allowing less room for critters to get into the roll insulation.
2. cost factor. it is more cost effective to use both materials rather than a thicker foam board. using both materials will give me a higher R-value while keeping cost down.
My main question is, if I proceed with this application is do I use faced or unfaced roll insulation? From my limited knowledge, foam board acts as vapor barrier. If I use faced roll insulation, will that create a cavity that cant breathe?
I am also open to other suggestions on how to best insulate the underside of the dome!
Please be kind, I am not a professional! just doing my best and trying to learn as much as possible!
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