Is this an example of shoddy contracting and/or building code violations for a house built in Tennessee twenty years ago? exterior facing wall light switch, no fire caulk on edges/holes, w/ cold draft coming through...

Weirdest part of all though... when I put my eye close I can see a light shining through the red plastic cutouts! (Really curious why is there light inside my wall, although that is not my primary concern.)

As for what I've done so far: I read various articles about how to fix this and a lot said just to use a foam gasket. But one site said that won't prevent airflow through the center and you need to open it up and seal all the edges and wire holes with fire caulk. red light shining through drafty junction box

Update: I applied fire caulking all around the top bottom left and right edges then used standard foam gasket cutouts. Well, the cold air is no longer leaking from the edges but now there is cold air flowing through the center holes but at least the airflow seems to be less now.

  • 1
    Assuming you took the picture during the day, the light is probably sunlight coming through whatever crack the draft is coming through.
    – Moshe Katz
    Commented Jan 30, 2022 at 23:58
  • @MosheKatz yes it doesn't show at night. It just baffles me how that much sunlight can be in the middle of the wall. Commented Jan 31, 2022 at 0:13
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    If you have a crack of the correct size, it can act as a lens, spreading the beam of light so it looks like the whole inside of the wall is lit up.
    – Moshe Katz
    Commented Jan 31, 2022 at 0:16

1 Answer 1


The draft coming through is because the outside of the house (outside the exterior sheathing, but inside the siding) wasn't air sealed very well. It's a common occurrence in older houses (like mine, built in the 1890s, last resided in the 1960s or '70s), but one built in 2000 should have been well sealed.

Electrical boxes aren't air tight by design. Not that they need air flow, but they're not designed to be air tight. If you go to your local big box store and take a wander down the electrical supply aisle, you'll see that nothing, not the boxes (plastic or metal) or the cable clamps or anything else has air tight seals. Boxes designed for outside use are mostly water tight, but I'm quite certain that there's still plenty of air flow in and out of all my freshly installed exterior outlet boxes.

All that to say that the only shoddy workmanship wasn't the electrician's fault, but the framers' or siders' fault for not doing an adequate job of sealing up the house wrap. However, your house may not have been spec'd for such a tight installation.

It sounds to me like your spray foam and gasket job were the right things to do. You indicate that there's still air leaking through "the center holes". I'm not sure which ones those are, exactly, but you may consider trying to add some extra air blockage if it's still bothering you that much.

You might also consider doing an inspection of the outside of the house itself. Look for cracks, leaks, rotting wood, etc. that would be allowing so much air to infiltrate into the inside of the walls that you're feeling it blow out of this box. Additionally, consider if it's just this one box or if it's all of them or several along a specific area of the house. If it's just this one, then it's possible that somehow the insulation in this particular stud bay was either missed or is no longer functioning as it should and you may want to consider repairing the insulation.

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