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How to air seal garage ceiling lighting

Matthew_M | Posted in General Questions on

Is there a good, air tight ceiling receptacle or air sealing method for regular round j-boxes in a ceiling, or would it be best to do something else?

I will have conditioned space above the garage and in a hurry to prep for sheetrock I specified regular ceiling j-boxes for ceiling light receptacles.

I’m no longer in a hurry to sheetrock and everything is still open, so I’m reconsidering this. I thought there would be some “air tight” ceiling receptacles but so far I haven’t found any. I figured I would be caulking and foaming each of these as my air sealing detail.

There’s 12 receptacles all wired up up there, but nows the time for me to change it if I should.

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  1. Expert Member
    1. Matthew_M | | #2

      These don't appear to be available anywhere. I'd seen them in the past on that Canadian home depot site, but not anywhere else well known or, local.

      1. Expert Member
        MALCOLM TAYLOR | | #4

        Regional things like that are funny. Builders here in Canada have been using them for several decades. I've never seen anything else on exterior walls and ceilings. Why they haven't penetrated the US market is a mystery.

        1. Expert Member
          BILL WICHERS | | #5

          Malcolm, Canadian construction stuff is just different enough from ours in the US to keep everyone on their toes. Your T90 wire is nearly identical to our NM-B wire, for example. Our colors are white, yellow and black for 14, 12 and 10 gauge, so color coded by gauge. You guys up north of us like to color code by function, so blue for AFCI, red for 240v only (I like that idea, BTW), etc. similar but different.

          What is with your two types of polyethylene water pipe though? I helped my brother in law fix a water well at his house, and your poly pipe (not pex, this is the black stuff) is much softer than ours. It’s rated for pressure and potable water though, so I’m not sure why the two different types?

          BTW, for the OP: you can probably get boxes like Malcolm recommended through a commercial
          Electrical supply house. I’ve seen them used before, and the box stores tend to not carry the less common and more interesting electrical stuff.


          1. Expert Member
            MALCOLM TAYLOR | | #6

            Another difference is our plastic fixture and outlet boxes all have a metal strip from the ground screw to one of the cover-plate screw holes. Funny how something is seen as essential one place and not another.

            I didn't know they still sold the old thin-wall poly. All the stuff I've done in the past few years has been thick-wall with exterior fittings.

            The thin-wall was a lot easier to work with. I used to be in charge of a small water system with around 600 yards of waterline buried about a foot deep. Black bears would hear the water flowing, dig it up and bite holes in it. A plastic barbed-fitting and a couple of hose-clamps and you were back in business.

  2. KevinEJ | | #3

    I'm putting plastic ceiling boxes in a cathedral ceiling for pendant lights. I plan to either diy foam boxes like Myron here (but smaller) or install the EnergyBlock ones -

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