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Community and Q&A

Ceiling insulation with polyiso

Allamon13 | Posted in General Questions on


I appreciate the help I have received in the past. I have R7.8 EPS foam on the exterior of my house with an R21 unfaced fiberglass on my interior walls! Thank you for the help on that portion of my build!

Anyways, I work in the foam industry and have access to polyiso scraps that are 30″ wide and range between 8-10 ft in length for free. It is R12 in value for 2 inches. I am wondering in my zone 5 (Pittsburgh region) if I were to dry fit my ceiling with 1 board am I able to use kraft faced fiberglass with the paper touching the board itself or should I remove the kraft facing? My plan is to dry fit and foam seal the perimeter. Then place the fiberglass insulation upside down for my region. My house already dries inward due to the exterior foam and I don’t believe this should be an issue but was looking for any second opinions…

Thank you!

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