Foam rafter baffles with interior foam as well
I have looked quite a bit but have not seen this explicitly discussed.
We are planning on using vented rafters with dense packed insulation. With 2x12s we will also need to add another R10 of insulation below the rafters in the form of rigid foam.
Planning to tape and air seal that interior foam as best I can.
The baffles will be site built, but I don’t know what material to use.
1/2″ OSB would be easy and I’ll already have piles around the construction site.
1/2″ Plywood may be better?
Air seal either one and leave it at that. I do wonder about condensation on the interior surface? It seems that enough people do vented attics this way so maybe it turns out not to be an issue if you air seal the interior correctly.
That being said, 1″ poly iso foam board is about the same price or cheaper than 1/2″ plywood – so I wonder if that’s a good upgrade. For the same price, it’s adding R.
I hesitate because I imagine that might prevent the rafter insulation from drying to the outside or the inside. Maybe foil-faced is not permeable enough and it should be something like EPS?
The problem is I probably have read just enough to confuse myself.