How to bury electrical in concrete wall
GreatWhiteNorthGuy
| Posted in Construction Techniques on
Hey Fellas! Super simple question, but I can’t figure this one out. I have a fella who’s going to be pouring about 50′ of 8′ retaining wall for me and I have to install electrical boxes at the 7′ mark for wall lighting. Now, the forms are rented and you’d pay dearly if holes were put in them. How do I secure boxes to the forms so they don’t get lost in the pour but will stay securely behind once the forms are stripped?
I’ll connect the boxes via plastic conduit and run a pull-string through the whole works, but I’m kind of at a loss how to anchor the boxes. This is a no-brainer you cement guys can probably answer with a chuckle. Thanks in advance for you help.
Cheers,
Ken
“They don’t build ’em like they used to” And as my Dad always added… “Thank God!”
Replies
Great White,
Man you don't make it easy .. All I know is putting screws thru the forms
Set the inside forms first , lay up the conduit and boxes, wire the conduit tight to the rebar.
Tape and seal every connection !!! Caulk if in doubt, mud gets in those conduit and you are in for a long fight .. trust me , just don't ask how I know.
Now what we do is run screw thru the forms and into the boxes, at times I have placed wooden blocks inside the boxes so that I can use Piffen Screws to hold them .
If it really is "NO Holes" at all , I can only suggest a bead of sealent on the face of the box and tape it to the form until the sealent sets.
What is a piffin screw??????????
Curley, It is a joke. A long time ( and record holding for # of posts) poster here uses "piffen" as his knick name here. He is adament that sheet rock screw (piffen screw) are not to be used for anything but sheet rock. He is correct , but it had become a joke here at BT long, long before I came here. Congrats , you now know one of the secret signs of membership. ;-)
Hot glue or foam the box to the forms.
Do you mean the same foam used to seal gaps around windows and the like? How would you keep the foam from causing voids in the concrete around the electrical box? Thanks for your suggestions, MarkH.Cheers,
Kem"They don't build 'em like they used to" And as my Dad always added... "Thank God!"
You hit the question perfectly. I doubt foam will work, any caulk , sealent, adhesive would have to be able to adhere to an oily surface which makes it tough to use them . Perhaps another way , again with holes, is 1'8" holes with tie wire threaded thru them and wrapped around the boxes and pulled tight. I really know of no way to hold the boxes without some form of holes or screws being used in the forms.
Thanks, dovetail. I think screws are the way to go.Cheers,
Ken"They don't build 'em like they used to" And as my Dad always added... "Thank God!"
The form would have to be cleaned off very well where the box goes. Glue a 3/4 thick plywood block on the form, stick the box to that, (plywood goes inside box). Or put a flat cover on the box and stick that to the form, or have some extremely strong magnets hold it to the form. Hard disk drives have some unbelievable strong magnets inside them.
I'm going to invent a rare earth magnet system just for that.
Thanks, MarkH. I've got some ideas now. Provided the boxes don't get knocked loose during the pour it should be pretty easy.Cheers,
Ken"They don't build 'em like they used to" And as my Dad always added... "Thank God!"
Course, YOU'RE screwed if they fall off.
What hold the forms together? Snap ties? Screw/tape/rivet/glue the boxes to those.
Or wedge them in with something that will stay in the pour - like the rebar.
Be sure to duct tape over your box and glue the joints!
used to swab grease inside the boxes, or shove an oversize foam block inside, then just screw the box to the form.
or you could use some roofing nails and clinch them
..are these metal boxes?
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, wer ist jetzt der Idiot ?
I assume you have a rebar grid in that wall. Stuff the box with styrofoam to keep concrete out. Use scrap iron or rebar to build a bracing to hold it against the form and tie this to the rebar grid.
Another possible method would be to cut a piece of PVC (pipe, rod, whatever) that fits between the forms and tie the outlet box to that. If you use pipe, you'll have to fill the pipe with patching concrete later.
Yet another method is to do the same thing with wood. Once the forms are stripped, chisel the wood out and fill with patching concrete.
I've seen all three used in commercial jobs in Georgia.
George Patterson, Patterson Handyman Service
Thanks to all. I'm going to wire and brace the plastic boxes to the rebar and I'll also fill the box with foam to prevent concrete from getting in. Cheers,
Ken"They don't build 'em like they used to" And as my Dad always added... "Thank God!"
fill the box withfoam.. you don't intend to squirt that expanding gunk in them,? do you?.
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Nah, maddog3, I'll cut some SM and fit it to the box. Pry it out later.Cheers,
Ken"They don't build 'em like they used to" And as my Dad always added... "Thank God!"
Common practice is duct tape over the opening, two layers , one ea. way .
Even better, dovetail. Thanks for the suggestion. Sometimes the simplest ideas work the best.Cheers,
Ken"They don't build 'em like they used to" And as my Dad always added... "Thank God!"
Just wrap it all the way around the box. it cuts out with a utiliy knife later when the form is stripped.
OK one more anecdote, On multi-story deck pours we used cast fittings that were made specifically for concrete, they got nailed ,or screwed, and had threaded hubs that we would run a nipple in and just mount a box to...after the forms were stripped.not good for your install this time . just something for the memory banks shove something inside either foam or paper in case your walls get vibrated,.
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This reminds me. Back in 1953 we bought some land for a nursery (landscaping). We put up a building for the business. It was had a ramp down to the basement level to bring in supplies and materials. The first floor was all workspace with a concrete floor. And the 2nd floor was temporary living space until a house was built. It was designed so that it could be split up into 2 aparments for tenates latter.I don't remember much of the detail of how it was constructed. Specially the elevated concrete slab for the first floor.But my father had been an electrican. And to allow for latter access to the basement for running pipes or wiring he put some clay flower pots, filled with newspapers, in the forms before pouring. That way they only needed to break through 1-2" concrete to get a hole through the slab.Also I still have some of his rotory hammer drills for going through concrete. Or at least part of the them.Star drill. You put them upto the contrete and hit then end with a hammer. Then rotated the bit and hit it again..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
clay pots !! how the old work was done.. has always been a source for wonder , and without the luxury of just picking up the phone and ordering exactly what you need .....like tapered deck cones !!!but that #$%@#¢% star drill was on many union tool lists until just recently, man I hated that Go%†©#? thing and my 3# hammer
....threw the drill away , kept the hammer but it was a lot quieter than the power tools that were showing up and most of those were no day at the beach either...like the Rockwell Kango.
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duct tape works too...heck newspaper was the choice for stuffing the boxes, but is a pita in freezing weather on large pours..
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