My garage will have 12' sidewalls of which first 6ft. is 6" poured concrete then 6ft of 2x6s. I am planning to fir strip the concrete for drywall installation. Need some suggestions on how I should route wall outlets switches. Firring strips will not give me the depth or protection for outlet boxes and Romex. I prefer the outlets to be flush with the drywall. Only two solutions either route the romex in conduit over drywall with outlet/switchs sticking out or carve out concrete to accommodate boxes. I don't want to frame out the concrete with 2x4s. Thoughts?
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Wiring a concrete wall
- Thread starter Theruse
- Start date
Thanks. I see how that type of box would work, but running the romex behind drywall with only furring strip doesn't sound safe.
Can use conduit for a sleeve
Boxes in concrete pours generally use masonry boxes that finish flush with the concrete wall surface. Pipe would be stubbed up into the framed section. There is no easy way to do what you want to do. You could use 2 x 4's to fur out the wall which will do what you want.
I've done a lot of flush boxes in concrete. Its turns out really clean. I would suggest planning for a few JB's up in the framed wall, and stub-up ENT or PVC out the top of the concrete pour. The easiest setup is to have the inside form wall put up first, and mount your boxes to it. You can use masonry boxes, but I've had good luck using 4x4's (with mudrings) wrapped with cheap packing tape to keep out the slurry. I can elaborate on more tricks if you like this route.
Otherwise I'd look at doing full surface EMT for everything. Boxes and straps attach to concrete with wap-pins, tapcons, etc.
Otherwise I'd look at doing full surface EMT for everything. Boxes and straps attach to concrete with wap-pins, tapcons, etc.
Terry D
Well-known member
The best way is what Bert has already mentioned. You are already planning on 3/4 furring strips anyway. Just use 2x2's or a 2x4 flat on the concrete. That plus the drywall will give 2 inches. A metal 4x4 1 1/2 deep with a 5/8 mud ring will bring it out flush will the finished surface. Note - Metal mudrings are 1/8 inch shallower than their size, so a 5/8 one is actually 1/2". Just sleeve the romex in EMT or use "Colorado Jims" to support the romex
https://images.homedepot-static.com/catalog/pdfImages/cc/cc92513f-2eb2-4550-9124-dc8c8239effc.pdf
You can put the boxes in the pour, but they will be flush with the concrete. By the time you put your 3/4 furring strips and 1/2 drywall, they will set back 1 1/4" from the finished surface, then you would have to use box extensions, which seems more work than what its worth.
https://images.homedepot-static.com/catalog/pdfImages/cc/cc92513f-2eb2-4550-9124-dc8c8239effc.pdf
You can put the boxes in the pour, but they will be flush with the concrete. By the time you put your 3/4 furring strips and 1/2 drywall, they will set back 1 1/4" from the finished surface, then you would have to use box extensions, which seems more work than what its worth.
itllgrowback
Active member
When we rebuilt our brick 1948 house we decided to abandon all the existing 2-wire cloth jacketed electrical which was routed through the brick, and run new circuits everywhere. The inside was finished plaster over brick, and so we furred out the interior of all perimeter walls with 2x2's and ran all new home runs throughout (along with Cat5, coax, speaker wire, empty conduit for the future etc). Then we filled the cavities with blow-in cellulose insulation, and drywalled over that. Worked great. If you're planning to drywall anyway, I'd just use 2x2's for your furring strips and give yourself room to do whatever you want.
I like the idea of mounting the boxes to the inside form wall with PVC to the top of the pour. Since a contractor will be doing the pour, is this a common request. Do they usually mount the boxes or would they let me? I suspect they will not let me mount the boxes, etc. to the form as it would mess up their schedule. For my 24'x24' garage, it will most likely be no more than six outlet boxes and 2 or three 2 to 3 gang switch boxes.
Terry D
Well-known member
A electrician or electrical contractor usually does this, not the concrete contractor. I personally would not go that route, unless the concrete is your finished surfaceI like the idea of mounting the boxes to the inside form wall with PVC to the top of the pour. Since a contractor will be doing the pour, is this a common request. Do they usually mount the boxes or would they let me? I suspect they will not let me mount the boxes, etc. to the form as it would mess up their schedule. For my 24'x24' garage, it will most likely be no more than six outlet boxes and 2 or three 2 to 3 gang switch boxes.
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alfredeneuman
Well-known member
If you prefab them as a complete assembly (conduit, ell, connector, box,) it won't take long at all.I I suspect they will not let me mount the boxes, etc. to the form as it would mess up their schedule.
On metal boxes install the ground screws and pigtails before the pour, and on all boxes be sure to stuff them with newspapers and a piece of ductape over the opening both so the boxes won't fill with concrete and keep the threads on the front clear. Also put tape over the end of the conduit.