Insulating attic wall
goblue777
| Posted in Energy Efficiency and Durability on
My master bedroom and bathroom have a vaulted ceiling. The top part of two of the walls exterior side are in the vented unconditioned attic. The attic side of the wall is just osb panel.
Should I just treat this as basically an exterior wall? I was thinking of adding foil faced EPS to the osb to help add some r value, prevent potential condensation in the winter and reflect some attic heat back in the summer.
I live in climate zone 5. I am aware that the foam insulation would have to be at least r5 to prevent moisture issues.
Any tips would be appreciated. Or if I’m off base here let me know. Thanks!
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Replies
Yes, a wall between an unvented attic and an interior room would be treated as an exterior wall and would need to be insulated. I have done similar to what you describe in my own home, with 3" foil faced polyiso on the attic side over the studs, then R15 mineral wool between the studs. Interior wall is a smart vapor retarder (belt and suspenders), then drywall. I see no problem using foil faced EPS as you describe though.
I would put some effort into air sealing that wall as you go too. I did that in my own home as well, using a combination of sealant and canned foam.
Bill
I don't have access to the studs but I would think there's some insulation in there. That is a good point about air sealing though. I plan on air sealing the whole attic so that I will have to include that wall as well.
Thanks for the advice!