Author Topic: cutting away rigid foam to put in an outlet?  (Read 1782 times)

nereo

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cutting away rigid foam to put in an outlet?
« on: July 30, 2016, 02:47:10 PM »
Falling under the "no home project goes without a hitch"...

I'm installing an additional outlet in my enclosed, 3-season porch.  At one point this was the exterior wall of the house but the previous owner added on the enclosed sun porch.

Ran the wires (romex) from another outlet to the location I wanted to pulled back the vinyl siding only to discover they had added 2" of rigid foam (shiplap) over the 2x4s. The foam is held in place by overlapping 1x3 furring strips.
 
Can I just cut a hole in the foam and install the outlet that way? If so, what do I attach the box to?  I basically want to put the outlet about where the two furring strips cross in the top left section of the photo.

Thanks for any input.


nereo

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Re: cutting away rigid foam to put in an outlet?
« Reply #1 on: July 31, 2016, 08:09:19 AM »
Bump.
Anyone?

I know I can cut back the foam (and later re-seal with spray foam), but the attachment part is the bigger concern. 

Metric Mouse

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Re: cutting away rigid foam to put in an outlet?
« Reply #2 on: July 31, 2016, 08:29:48 AM »
These are the style of boxes I installed. Would they not nail to the 1X side of the furring strip? If the nails don't work, in 'non-standard' layouts I've run screws through the side of them, making sure they're flush so they don't contact any wiring.

http://i.stack.imgur.com/lfrWo.jpg


Not fully understanding the layout of how it's mounted/enclosed, but they also make 'low profile' outlet boxes as well for shallower depths.

bobechs

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Re: cutting away rigid foam to put in an outlet?
« Reply #3 on: July 31, 2016, 10:26:46 AM »
If you are asking if you can just gouge out enough foam to cram the  box in and then just close it all up with the box floating behind the siding and box cover -- you can but you shouldn't.

The box should be fastened to something made of wood other than back of the siding itself.

Just a suggestion -- take out enough foam to place a short length of 2X4 beside the box to bridge the gap to the furring strip.  Screw or nail the whole contraption together and for good measure go ahead and run some long construction screws back into the structure behind the foam sandwich.

Sure it will look like ass and the humiliation of knowing that it is behind that panel will eventually drive you to sell and move to a house where everything --every little detail-- is perfect.  But that's just the way it is.

zolotiyeruki

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Re: cutting away rigid foam to put in an outlet?
« Reply #4 on: July 31, 2016, 11:25:05 AM »
The two furring strips give you 1.5", and the drywall will give you another 0.5", so you should have enough depth to put in a shallow outlet box if need be.

For an anchor point, I'd take another piece of 1x4 and slide it behind the vertical piece, effectively doubling it up.  Glue/screw it in place, and that should give you a suitable place to nail/screw the outlet box to.

nereo

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Re: cutting away rigid foam to put in an outlet?
« Reply #5 on: July 31, 2016, 11:30:15 AM »
thanks all.

To be clear, I do want to connect the box to something other than foam, but I've only ever mounted boxes to 2x4s before, never to the 1x side of a furring strip.  I'm thinking bobechs/zolotiyeruki's suggestions to add some more wood behind the furring strip to give something a bit more 'hearty' for the box to attach to is the best option here.



paddedhat

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Re: cutting away rigid foam to put in an outlet?
« Reply #6 on: August 01, 2016, 07:47:18 AM »
Nereo, this one is easier than it looks. Google "Arlington vinyl siding mounting block". They make a receptacle box, with a mounting flange, and a vinyl siding trim ring.  Grab one at Home Depot,  mount the nailing flange to the face of the existing furring strip using a few short galvanized roofing nails, or screws, then add another furring strip to support the other side of the flange, and screw it down.  Cut the siding about 1/4" bigger than the edge of the box and snap the trim ring on. That's it.