New roofing over unconditioned attic — any recommendations?
We have an unconditioned attic and will need a new roof soon. I looked into creating a conditioned attic but for various reasons (old rafter structures, hard to find experienced contractors, cost) that is not going to happen. We have gone with ceiling mounted mini-splits (MLZ-KP09NA), so we did get (most) of the ducts out of the attic, just two for an UltraAire 98H (which will be buried under cellulose).
We’re in Austin TX so we get a lot of strong sun. Is there anything that can be done in a smart way during re-roofing? We will probably go with a metal roof, and I think I should be looking for high solar reflectance index (SRI) values. I’ve read about Kynar any other suggestions? Worth worrying about? We will likely go with a vapor open, 3D, sub-roof membrane, such as Solitex UM.
Beyond a roofing with high SRI anything else that can/should be done? We don’t have a ridge vent, should we be thinking a vapor vent, as discussed here, although that seems only relevant for conditioned attics? https://buildingscience.com/documents/insights/bsi-088-venting-vapor Perhaps having a vapor open membrane and 3D space above the membrane makes that irrelevant anyway.
Would a small layer of insulation under the roofing, even with an unconditioned attic, help with high radiant loads from sun, or is that screwy thinking?
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