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Bathroom Insulation in Florida – Vapor Barrier Question

Blake Lasslett | Posted in Energy Efficiency and Durability on

I’m doing a bathroom remodel due to some water damage from the old shower and wanted to know the best approach for my insulation since i’m in a warm and humid climate. The exterior wall previously had thin fiberglass between the furring strips and then a plastic vapor barrier and the ceiling just had old compressed blown in fiberglass.

For the walls I planned on using 1/2″ R3 foam board between the furring strips but do need to add the plastic afterwards? On the ceiling I was going to use R19 in between the 2×4 trusses and then R30 running the opposite direction on top, both unfaced and no added vapor barrier. I’ll have to secure them in place somehow before I put up the drywall because this is towards the end of the roof and there isn’t much room to work from the attic. Does this sound like a good plan?

Because it is a bathroom, I just want to make sure i’m doing it right so I don’t have any mold/moisture issues in the future. I did buy a quality High CFM Panasonic fan with timer switch so that should keep down the moisture from the shower.

Any input would be greatly appreciated.

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  1. User avatar GBA Editor
    Martin Holladay | | #1

    You haven't described your wall construction type. Because your wall has interior furring strips, I'm guess it's a concrete block wall (CMU wall). Did I guess correctly?

  2. User avatar GBA Editor
    Martin Holladay | | #2

    While an insulated wall in Florida generally doesn't need an interior vapor barrier, every type of shower needs some method of protecting the wall from water damage.

    What type of shower enclosure will you be installing? Will it be a one-piece fiberglass shower? A kit with a separate base and plastic wall panels? Or will this be a ceramic tile job?

  3. Blake Lasslett | | #3

    I have two walls that will need to be insulated. One is concrete block with furring strips and the other is just a 2x4 wall with the garage on the other side. As for the shower, I will be doing a ceramic tiles with Durock. For the ceiling I bought the green mold resistant drywall. This weekend I'll be focusing on insulating the ceiling and then adding drywall.

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