Proper mounting exterior boxes prior to stucco...

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Old 08-29-09, 02:55 PM
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Proper mounting exterior boxes prior to stucco...

Hi all,

I didn't get much of a response in the Stucco forum, so I'm reposting here.

I need to mount up about 5 or 6 exterior boxes for lights and switches. The house is plywood skinned, awaiting stucco.

I'm looking over the methods that our electrical sub used for the front porch light and stair light and I'm not impressed. I can't comprehend how the porch light box is supposed to support the light of the fixture, and both boxes look like water intrusion points in the making.

But I'm having trouble finding any info online on the proper way to do this, with off-the-shelf kit from Home Depot or the like.

I came across some "old work" round boxes today that require a 3-1/2" hold saw, and look like they might seal well. I also came across "mud rings" for square and round electrical boxes that would get the required offset to cause the edge of the box to sit flush with the stucco exterior.

Can anybody direct me to a website that describes a good way to install boxes prior to stucco. The walls in question are all accessible from the inside, so I'm very flexible.

Below are a few pictures of the two boxes our contractor's electrician put in. I'd like to hear any comments on these, as well.


This is the box over a front door, which is supposed to be encased in stucco and will be supporting a 5 or 10 pound porch light. I'm not impressed with the large gap around the circumference, and don't know how it will be waterproofed.




This is that same box viewed from the back side. As you can see, it's just a metal rail meant for ceiling fixtures. At minimum, I'm thinking the rail should be replaced with a 2x4 to better support the weight of the fixture.



This is a box that will house a fixture lighting the front stairs. Again, a wonky assembly -- though it actually looks more sturdy than the one for the porch light.

 
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Old 08-29-09, 03:35 PM
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Any penetration through the sheathing will leak no matter what you do. The stucco will run up to the box edge so you shouldn't have to worry much about water. I suggest using caulk and expanding foam to fill any gaps.

I also suggest using these boxes for your receptacles to meet code (2005) for an in use cover: Arlington DBVM1W In BOX for New Stucco and Textured Surfaces

Here is some box kits for light fixtures: Aluminum Siding Block - Wholesale Electrical Supply Company
 
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Old 08-29-09, 05:59 PM
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I would also like to jump in on a similar quesiton to this. My house was built in 1928. The lights over the exterior doors are supplied just by a wire poking through the cedar shingles. What would be the best way to install a flush mount box to replace just that wire and still keep the water out.

The light above my back door was shorting out in the rain. That's how I came to learn of this situation. So I used an extension ring with a foam gasket to take care of the issue. But I would like to have something more appropriate at some point.
 
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Old 08-29-09, 06:24 PM
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Originally Posted by Tolyn Ironhand View Post
Any penetration through the sheathing will leak no matter what you do. The stucco will run up to the box edge so you shouldn't have to worry much about water. I suggest using caulk and expanding foam to fill any gaps.
And do you have any opinion of the strength of the mounting arrangement for the can supporting the porch light? Because this, in particular, is something I need to duplicate in 4 locations along the back and side of the house.

I suspect "more rigid" = "less wiggle" = "smaller gap for water penetration" ?

Thanks.
 
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Old 08-29-09, 08:12 PM
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Again, the stucco will be put on around the boxes you have right now so I really doubt their will be much wiggle. You will likely have gaps between the finished stucco, due to the rough surface, and the light fixture. You might consider the light boxes I posted.

I still suggest caulk applied on the outside before the stucco is put on to keep out water. And expanding foam in the inside to stop air.

I would, however, replace the receptacle boxes with the Arlington boxes I posted. You will otherwise be required to use "bubble" covers. (not pretty)
 
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Old 08-29-09, 08:35 PM
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I will do the same thing as Tolyn do the samething with the in use box for stucco wall set up.

I know some big box store start to stock this item but pretty good percentage electrical supply centre do have them on hand or order it pretty quick.

And I done few of them and it work out good for that set up.

Merci,Marc
 
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Old 08-29-09, 08:44 PM
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Originally Posted by speede541 View Post
Hi all,











Normally I don't say this in the fourm but I think your electrician subcontactor is not really do a good job at all I can spot few issue allready there I will never do that kind of work espcally someone did use the oldwork single gang box on the exteral wall like that.

Merci,Marc
 
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Old 08-30-09, 06:56 AM
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These look like a good solution for your lights.

Flange Box for 1/2" or 1-1/4" Surfaces

Like Scott, I would suggest the receptacle box he linked to. Less likely to have the cover broken off compared to the bubble covers.
 
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Old 08-30-09, 02:43 PM
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In the case of the receptacle box pictured, it's for small surface-mounted step light -- so I wouldn't use one of those covered boxes there (without the cover), right?

 
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Old 08-30-09, 02:56 PM
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Correct. If it is for a light, then no in use cover needed and no special box needed either. The are only required for the receptacles on the outside. (which I assume you have as a minimum of two is required)
 
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Old 09-30-09, 03:01 AM
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I'm posting back to say thanks for the links / advice.

I tracked down Quickflash locally (a shame that the Allied Moulded outlet boxes they're required to be used with weren't carried by the same seller), and also the Arlington "In Box" (be advised they have a similar metal box, too).

I used three different methods of installation on the Quickflash boxes, depending on the box type. On the round boxes, I mounted a 2x4 between the studs, then fastened the outlet box directly to the face of the 2x4. This allowed me to set the depth precisely, and gives me a solid mounting (unlike that metal hanger setup in one of my original photos) to better support the weight of the light fixture that will eventually be attached.



Arlington In Box:
 
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