I have posted here before about retrofitting my house with spray foam and turning it into an unvented attic. I have since realized that this will be a huge waste of money since my home is already set up and insulated with batt insulation. So, I would like to add to or correct what I have and go with it. Ive talked to a few pros and the only ones suggesting I do spray foam are...well, the spray foam companies. Everyone else actually suggests I add to what I have or don't add anything.
I have a few areas in my unfinished second story that are cathedral or cold cieling setups. The house has a metal roof with tech shield radiant barrier. Between the 2x10 roof rafters in these areas is R19 insulation that is installed in a 'cupped' fashion to preclude the use of baffles and facilitate air flow from the soffits to teh attic.
The issue is that I live in Zone 2, near Houston, TX and I think this is technically under insulated. My living room is done this exact same way, but its already finished and Im not in the mood to pull drywall down to re-do it.
So, in the areas I still have control over, how can I address this? Does it even need addressing since it has a metal roof and radiant barrier? Should I simply add foam board and get close to R30 as possible? If so, should I remove the facing from the batts before putting rigid foam board on the rafters?
Any advice is welcome. I would like to to this as correctly, but price effectively, as possible.