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Drilling a hole through a ceiling double top plate (two 2x4s)

Drilling a hole through a ceiling double top plate (two 2x4s)


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Old 08-13-13, 07:27 PM
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Drilling a hole through a ceiling double top plate (two 2x4s)

I am renovating the TV living room wall and want to run a lot of audio/video cables through a stud cavity up through the ceiling double top plate (two horizontal 2x4s) and into the attic.

I just want to know... Is it ok structurally to drill a 2" hole through the ceiling double top plate (two 2x4s)? What is the max size hole I can do? Any idea if I should use an auger bit, spade bit, or something else?
 
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Old 08-13-13, 08:30 PM
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I use a nail-eater auger bit because it gets me through quickly and it has a lifetime warranty.

The diameter is 3/4" or 7/8" - I have one of each. That's pretty much the largest hole you should make in any nominal 4" - actual 3-1/2" - framing member.
 
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Old 08-14-13, 11:20 AM
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Oh no. How am I going to fish a bunch of speaker wires through a hole less than 1"?
 
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Old 08-14-13, 12:43 PM
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You can drill multiple holes in the same section...just space them apart by about 1" or so. And I think you can drill larger holes as long as the joists/beams resting on the top plate are directly above the studs. If that is the case, the top plate is not really supporting any load, it is only acting as a horizontal tie and nailer.

Still better to drill several smaller holes in the same stud bay.
 
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Old 08-14-13, 03:24 PM
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Code-wise, not in Texas without a repair of sorts- under the IBC.... Texas Building Codes


Pages 4-5; http://www.google.com/url?sa=t&rct=j...,d.cGE&cad=rja

Gary
 
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Old 08-14-13, 04:37 PM
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Gary....I'm having a big problem viewing PDfs for some reason. Were you replying to the one big hole or multiple smaller hole statements?
 
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Old 08-14-13, 05:53 PM
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From what I can see, pages 4 & 5 apply primarily to plumbing, and this is not plumbing. Since this is an electrical issue, page 10 would apply (Texas electical code: NEC 2008) which allows up to a maximum 1" hole without a protective plate, if it is exactly centered on the 2x4 plate.

It sounds to me like you would just need to drill as many 1" holes as you need, and make sure they are centered in the plates.
 
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Old 08-14-13, 05:56 PM
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I think 2" is a pretty large hole to drill in the header. When I've drilled for wiring in an outside wall I've never drilled larger then an 1-1/4" hole. Woodbiter (auger) bits are good. A little tough to get in a tight squeeze. Usually I'll use a speedbore bit.


I see by Gary's Texas Building Code link that Texas follows the IBC and apparently there are no penetrations allowed in the load bearing plate. That seems to be extremely prohibitive to me buy I don't make the codes.

Thanks to xsleeper it appears that holes can be drilled for wiring.
 

Last edited by PJmax; 08-14-13 at 06:19 PM. Reason: Corrected info
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Old 08-14-13, 06:08 PM
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Not to run the OP away...but the area between stud bays is not load bearing. PJ..your link talks about studs, but this isn't a stud or a header.

Still can't see the linked code for Texas.


How the heck are you supposed to run wiring in a single story home on slab of you don't drill through the top plate????
 
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Old 08-14-13, 06:16 PM
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Old 08-14-13, 07:07 PM
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PJ...I understand the protection thing...but I can only open the diagram with examples and it only shows piping in studs and plates.

I've been in several attics where there are 2 or 3 1" holes drilled for electrical in a double top plate and they didn't have any visible metal plates.


Ok...enough for now since I can't see the TX links....but I know that top plates are drilled all the time w/o metal plates. I mean...who the heck would be driving a screw or nail up there?
 
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Old 08-14-13, 07:29 PM
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Yes....according to what is written there.... like what xsleeper mentioned..... you can drill 1" holes in the center of a 2x4 header. So a row of 1" holes is it.

Tonic.... you'll need to assess your wiring so that you can make use of the 1" holes. If you plan to run any cables with ends.....they'll have to pulled in first.
 
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Old 08-14-13, 07:40 PM
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I think you also have to use some common sense when deciding how close to put the holes to one another. I think 1" is too close... you would need to separate the holes by several inches, since a row of 1" holes that is too close together would also significantly weaken the member laterally. I have also read somewhere that one hole per lin/ft is a good safe rule of thumb. There is some method for determining that spacing somewhere, but I can't find it.

Once the wires are run, don't forget to fire block the holes with spray foam.
 
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Old 08-15-13, 02:24 PM
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Nec

The NEC states that holes shall not be less than 1.25 in. from the edge of the framing. For a 3.5 in wide 2x4, the maximum sized hole would be 1 in. placed in the exact center of the 2x4.
 
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Old 08-15-13, 09:51 PM
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Uh oh. I broke the law. I mean the NEC Code. I hope I don't get in trouble with the local zoning enforcement people.

I intended to do a 1 1/4" hole, but I accidentally grabbed a 1 1/2" holesaw. I didn't realize my mistake till just recently. Seems like I probably shouldn't have gone over 1", but NW I have gone way over. What should I do?
 
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Old 08-15-13, 10:23 PM
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Two options.

1. Burn your house down.

2. Slap yourself forty times with a wet noodle and then move on with your life.
 
 

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