Bathroom over an unconditioned garage
I recently started reading/researching the topic of building science. I have long term plans to build a house for my family one day or at least self perform as much as possible. I have been around residential construction all my life, but in this part of the country (SW Ohio, Climate Zone 5) building science is seldom a primary thought on a new home site. It’s, OSB sheathing, 2×4 walls, fiberglass batts, and brick veneer or vinyl siding. In starting to do my homework for our own future build (5-7 yrs from now) I realized that I made mistake in the remodel of 2 bathrooms at my parents’ house.
The new bathrooms sit above an unconditioned garage, the garage is part of a walk-out basement. The garage had a dropped textured drywall ceiling before we re-constructed all of the plumbing to sit inside of the 2×10 joist bays, instead of below them. The garage has limited headroom so this 6″ of headroom gain was a major plus.
After the work was complete we stuffed the joist bays with 3 layers 4″ fiberglass batts (they were left over from other parts of a remodel) some of it had a foil face, but not all. Then all of that was covered by 1/2″ OSB. Other facts, this is a 12’x8′ area with exterior rim joist along one of the 12′ lengths.
My concern now, knowing what I have learned in the recent months about vapor, and the importance of air sealing, is that I have created a problem where cold air from the garage could travel through the poorly air sealed OSB ceiling and condense on the under side of the new OSB sub-floor that sits below concrete board and porcelain tile. It has been in place about a year now.
I know now that what we did was incorrect, but my question to this group is should I be speeding over to start ripping all this out, air seal all floor penetrations, and remove any foil faced batts. Or is it possible that while what I did was grossly wrong it would be permissible to leave in place. The more I listen to the FHB Podcast and read on this site, the more sleep I am losing. 🙂 So I am asking here to get some confirmation, either way.
Thanks for reading my wordy post!
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