Sealed grow . . . 6 mil plastic needed behind sheetrock?

Discussion in 'Grow Room Design & Setup' started by HydroDawg421, Feb 28, 2018.


    HydroDawg421 Well-Known Member

    I'm building a new home and the detached garage will have a 15x19 sealed grow room. All (4) 9' walls and the ceiling will have spray-in closed cell foam insulation.

    Do you think it's necessary to cover the walls with a thick heavy black 6 mil plastic prior to installing the purple sheetrock?


    OldMedUser likes this.

    GNOME GROWN Well-Known Member

    It wouldn't hurt. When I built my old glass blowing studio I put plastic over the insulation before sheet rocking the walls. It for sure helps imo.
    OldMedUser likes this.

    NaturalFarmer Well-Known Member

    I don't think it is necessary if you tape and mud well, especially if you are using foam behind it. I would recommend getting a roll of tuck tape (red sheathing tape) to seal you joints prior to mud. Stickiest and strongest tape I have ever found.
    OldMedUser likes this.

    BigHornBuds Well-Known Member

    One big advantage of the spray foam , is that once’s it’s dry it doesn’t need vapor berrier . It’s a sealed membrane.
    OldMedUser and SmokinDogCujo like this.

    brewbeer Well-Known Member

    Closed cell foam is a vapor barrier. If you were using an open cell foam, you would want to use a vapor barrier appropriate for your climate.
    Joint Monster and OldMedUser like this.

    thumper60 Well-Known Member

    if u r using outside walls an have snow on the ground 3-4 months a yr poly it cheap cant hurt.if its a room in a room don't bother
    OldMedUser likes this.

    OldMedUser Well-Known Member

    Any power outlets on an outside wall can get a lot of condensation in them too if you get cold winters. I take the cover plates off those, put a piece of plastic over them and screw the cover back on then just plug in right thru the plastic and get a good seal. Also don't vent into your attic unless you want it to rain inside come spring. I found out the hard way. :)

    I would put that cheap clear plastic over the insulation too. For a few extra dollars it's worth it.

    thumper60 likes this.
    cookie master

    cookie master Well-Known Member

    you are gonna seal in moisture and the whole thing will melt. Dont do shit like this yourself, trust some experts, not me.

    thumper60 Well-Known Member

    I have seen brandnew garage rotted in 1 yr from blowing into attic of cold air like u say it had been raining up there for months I have seen extearer walls warped from not using plastic on them,if it stays above freezing don't get that problem

    thumper60 Well-Known Member

    hes running seal room witch means co2 an a dehuy
    Joint Monster

    Joint Monster Well-Known Member

    This guy seems to know what is is talking about. While I am no contractor, I know that vapour barrier (plastic) is used over insulation for a reason, controlling moisture.

    However, Brewer says closed foam is a vapour barrier. So I would presume you are okay. You can always inquire with a contractor for a quote over the phone, and if they're a good contractor they will quote you for free and tell you if it is necessary or not. Then you can simply go forward by yourself.

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