I want to install a flood light under the eave of my house. I ran the electric from the basement through 2 floors to the third floor attic and into the eave already. I bought the flood light and a round surface mount box.

I asked a guy at Home Depot about the install and showed him this pic I took:


He seemed to know what he was talking about, but didn't mention anything about the eave covering. I then looked up how to do the install on YouTube when I got home and the first video I saw said to not install when the eave has a ridged covering with channels for airflow, which is what it looks like I have. The claim was that this could cause water to get into the box:


Should I abandon this little project or can I like, cut a hole in the either aluminum (or vinyl? - I'm guessing aluminum because that's what the garage has) covering to mount the electrical box?

This is the type of box I got:

  • Round Bronze Weatherproof Box with Five 1/2 in. Threaded Outlets



He has an old work box. You have exterior grade; you can put that wherever you want. If you're worried, use dope on the knock-out plugs and the fitting.

Drill a hole in the eve right up against a joist (1" hole saw, or however big it needs to be to actually fit the fitting - it's always bigger than you think). Put the wire through the hole and into the rear KO, then angle your screws to grab the joist. Or add some framing to catch a screw from the other eyelet. I wouldn't caulk anything.

In the future, always plan the end point before you begin.

  • Ok. Thanks! That's good to hear. I have a couple follow up questions. If I can install on top of this instead of cut a hole (as I'd imagined), how to I keep from warping/dimpling the aluminum from the compression? Also, I'm guessing there exist air-tight wire clamps in the box to get the wire through the KO without worrying about water getting in? And any tips on finding the joist through the aluminum - normally, I would knock the ceiling and listen for it. Can't imagine that technique would work here. I guess I could drill a hole and use my scope camera.
    – hepcat72
    Dec 30 '20 at 14:01
  • Could you explain further what you mean by "add some framing". I assume you mean some metal piece that I can both screw to the eyelet and into the joist?
    – hepcat72
    Dec 30 '20 at 14:10
  • @hepcat72 - I was going to mention: don't screw it down so hard that you smash the siding. Also assumed you had access from the attic. And that you're using EMT, BX, or water-tight (probably Romex, eh? That you might want to caulk). But if you're worried about water where it isn't supposed to be anyway, then that's a gutter problem. - It's flexible enough that you should get a pretty good idea where a joist is from pushing on it. (I won't tell anybody if you only get one screw in an eyelet ;) ... to add some framing you need attic access.
    – Mazura
    Dec 30 '20 at 14:11
  • Ah. Right. The attic is partially finished. I took up a couple of floor boards and am installing an outlet at the same time, which allowed me to feed the wire. I was planning to get one screw into a joist and I have an expanding anchor for the other (though with the gap the aluminum creates, that might not work. Finding the joist seems to be the part I'm most unsure about. My scope camera doesn't turn on its own.
    – hepcat72
    Dec 30 '20 at 14:21
  • I assume that the aluminum is covering wood? I won't be able to tell until I rent a 28' ladder. I peered around from the attic using my scope, but the color isn't good enough to be able to tell. I can try pushing to see if I can find the joist. Hopefully, I won't have to drill multiple times to find it.
    – hepcat72
    Dec 30 '20 at 14:30

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