Insulating Bathroom Ceiling

Old 05-20-19, 11:42 AM
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Insulating Bathroom Ceiling


I had mold issues in my bathroom ceiling due to no fan being installed so I tore down the ceiling and had the mold removed. I also just installed a new ceiling fan.

When I tore down the ceiling, there was no insulation in there. The bathroom has another floor above it and is in an old, thick-walled brownstone style building.

Should I install any type of insulation in the ceiling prior to drywalling? The bathroom did not seem to fluctuate in temperature that much when there was no insulation in the ceiling, but would the insulation provide any other benefit and help prevent future mold growth?
Old 05-20-19, 12:00 PM
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If the floor above is conditioned then no insulation is needed!

To get rid of mold you need to get rid of the moisture, hopefully the new fan is vented to the exterior of the house!
camham voted this post useful.
Old 05-20-19, 12:23 PM
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If the bathroom has an exterior wall, you need to air seal and insulate the rim joist with at least 2" of foam board, sealing the edges with PL300 or similar.
camham voted this post useful.

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