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Discussion Starter #1
I'm networking my house with cable, internet, & speakers. Everything is originating from an upstairs bedroom and I'll have 17 cables that need to go down through the top plate (sill?) of a non-load bearing wall, then through wall studs & some ceiling/floor joists to get parsed out to their respective destinations.

I've heard a lot of "suggestions" regarding holes. For example, you should try to avoid drilling holes over 1 1/4" inch diameter through a 2x4 wall stud and through 2x12 ceiling/floor joists. I've heard that "notching" out the edge of a 2x4 is worse structurally than drilling a hole through it, but "notching" floor/ceiling joists is preferred to holes? Any truth to any of these?

What are the best recommendations for stud and floor/ceiling joist hole sizes?


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Some questions specific to my project. A couple notes; I am in an active earthquake zone so structural integrity is very important to me. I have one HDMI cable which has a 1" head on it - it goes down through the top plate and through three wall studs. (I have to run 4 CAT8, 1 HDMI, 2 3.5mm, and 10 RG6 cables to route.)

What's the best practice for drilling down through the top plate/sill to fit all 17 cables? Should I bundle them up individually for each room and run each bundle through it's own smaller hole, or should I cut as big a hole as I can (1 1/4 inch?) then run as many cables as possible through each hole I have to cut? How far apart should I space such holes? Should I try to drill through as close to the existing downstairs wall studs as possible to lessen the structural impact?

On drilling through the wall studs, how far down from the top plate should I go before drilling through horizontally? How far apart should I drill these holes? Should I dead center the holes on the stud or stagger them on each stud? (IE hole toward the front on the first stud, then toward the back on the next stud, etc.) Should I drill the wall stud holes in a straight horizontal line across, or is it better to go up and/or down a bit on each stud?

Should I add a piece of horizontal wood between the studs where I drill through? (I thought that'd be a good cross brace & it'd protect the cables from nails and screws as well.)

Should I throw in more wall studs, I've heard stacking (sistering?) them lessens the structural impact of larger holes and notches.
 

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retired framer
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On line you will find rules for notching, we would not do that and expect it to pass city or engineer inspections, with floor joists you want to be closer to the end of the joists and holes can be in the middle 1/3 of the height and the hole can be 1/3 the height of the joists so a 3" hole in the center of a 9" joists.
Non bearing wall plates and studs, you want to stay in the center so you don't hit the wires with drywall screws.


Bundling the cables is more about the cables of which I have no info on.
 

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Discussion Starter #3
@Nealtw Thanks for the suggestions :) I actually only need to run two cables through the floor/ceiling joists so my hole will only be about 1" diameter - sounds like that'll be no problem for the 2x9's.

On bundling the cables, I was just meaning/talking about/thinking of drilling a bunch of smaller holes instead of a couple big ones to feed all the cables through.
 

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Naildriver
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I would drill several holes, smaller, for the runs. The 1" where you run the HDMI can house many of the other cables once the HDMI is in place. Additional hole(s) would accommodate the CAT8 and RG.
 
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Discussion Starter #5
I've been poking around random corners of the internet all day and I found code and discussion that indicates the following:

Holes in bearing walls may not exceed 40% of the width of the stud. Holes in non-bearing walls cannot exceed 60% of the stud width. Edges of holes must be at least 5/8" from the edge of a stud. Romex has to be 1 1/4" back from the front of the stud (to protect from accidental screwing) or a 1/16" thick protective metal plate has to be used. You cannot have a hole and a notch, nor a hole and a horizontal cut/butt joint in the same "cross section" of a stud [basically, you want some continuous meat around the hole/notch.] Holes should be round, cut an octagon if you cannot go round.

*There's also apparently an exception for 3" pipe holes in one 2x4 wall stud so long as you double that stud up; then you can go up to 60% of the studs width on load bearing walls. But you can't do that for two studs in a row [I think... it gets a little fuzzy. I guess they're saying if you have to run a 3" pipe horizontally through a wall, you need to make the wall studs 2x6.]

So 1 7/16" hole in 2x4 and 2 3/16" in 2x6 load-bearing walls, and for the non-load bearing walls; 2 1/8" hole in 2x4 and 3 5/16" in 2x6 walls.

They also talked about notches - I'm not personally keen on them as they are apparently not recommended, but for the sake of sharing my hunt results: notches in load bearing studs up to 25% of the studs width and up to 40% in non-load bearing studs. Should notch near the top, rather than the bottom, don't locate a notch near knots, and don't put too many notches in the same area.

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For the top plates and sills I found only discussion about the plates on "wood panel shear walls":

2x4 double top plates and 2x4 or 3x4 sill plates - 1 1/4" max hole diameter, and "the center of the bore cannot be more than 1 1/2 from the edge" [I believe they essentially mean it needs to be centered on the plate], and they need to be more than 1' apart (on center.)

2x6 double top plates and 2x6 or 3x6 sill plates - 2" max hole diameter, 2 1/2" max to the "center of the hole," and 1' OC minimum apart.

2x8 double top plates and 2x8 or 2x6 sill plates - 3" max hole diameter, 3 1/2" max to the "center of the hole", and 1' OC minimum apart.

I also found a number of references that non load-bearing top and sill plates can be bored up to 50% of it's width, and if you go more than 50% the width you have to put on metal strapping.

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For floor joists I found that holes may not be greater than 33% of the joists depth, and they cannot be closer than 2" from the top or bottom edge of the joists.

Notches cannot be more than 1/6 the depth of the joist nor greater than 1/3 of the joists length. Notches at the ends of joists should be no greater than 25% joist depth, and you cannot notch within the center third of a joists length. Also notches should not be perfectly square or rectangle because they apparently crack at the corners (aka cut a trapezoid shape instead of a square/rectangle.)

* I also read about something called "ripping" where folks apparently cut off the top of the floor joists to put down flooring (o_O) As one (on here) might expect, that is not at all a good idea.
 
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Naildriver
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Well, that was short and sweet. Lost me after the second paragraph. Basically plumbing walls should be 2x6 to accommodate normal piping. Doubling the walls helps, but you lose more real estate that way.
 
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Discussion Starter #7
I can't help that the codes are long winded!!

(Not that I'm not a rambler wall-of-text poster ;P)
 

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Mysteiss, thanks for all of that. In the real world, the carpenter frames the place, the electrician comes in and drills o through studs, plates, whatever to do what he needs, and the plumber comes and drills, notches, hatchets, whatever to get his pipes where they need to go. And THEN, the carpenter comes in and fixes everything!
 

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Discussion Starter #9
Mysteiss, thanks for all of that. In the real world, the carpenter frames the place, the electrician comes in and drills o through studs, plates, whatever to do what he needs, and the plumber comes and drills, notches, hatchets, whatever to get his pipes where they need to go. And THEN, the carpenter comes in and fixes everything!
:vs_laugh:

I have always had a fondness for carpenters.
 

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Naildriver
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And THEN, the carpenter comes in and fixes everything!
Like cut joists to install toilets, studs denigrated too much to hold a load, or removed wood to make their job easier. Plumbers have mommies, too, so lets not be too harsh on them.
 

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I’ve been “plumber’s helper” for a friend during a couple of rough-ins. Plenty of practice with the big hole hawg and the wrecking saw!!!
 

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Dupe.....and I can’t make it go away!!!!!!

I’ve been “plumber’s helper” for a friend during a couple of rough-ins. Plenty of practice with the big hole hawg and the wrecking saw!!!
 

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Discussion Starter #14
I think I've got a 3" pipe going through my 2x4 top plate. I'm a bit worried when we pull down the sheetrock, where the fridge punched the pipe through the load bearing wall in the game room, we're going to find that the top plate hole cracked from the quake :/

We're hoping to get to that next weekend, we had guests over two weekends ago and I decided to get sick this weekend so we weren't able to get started on it. I'm quite worried now considering a 3" pipe hole basically means the top plate in that spot is all kinds of useless.

In general the top plate is just to keep the walls from wracking though right? If I understand my engineering the load bearing wall just transfers the weight of the load down. You don't want the wall to start twisting out of plumb because then the load will "crush" that section... Like sliding a plate too far off the edge of the counter: it'll be fine as long as enough of the load is being transferred to the ground to maintain "balance," right?

I suppose it's possible there's a 2x6 in the floor or something, but any suggestion as to what I could add around the 3" pipe hole in the top plate if it's 2x4? Like maybe some 2x6 or 2x4 cross braces below the sill plate to bring the load back onto the wall studs? Or am I better off leaving it alone since it survived a 7.0 quake?
 

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If you have a 3” pipe, you would basically have no hole as 3” pipe has O.D. Of 3 1/2”,more likely a 2 1/2” pipe, with 2 3/4” od. If you are worried about it, just grab a mending plate and screw it in across the gap. Ron
 

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Discussion Starter #16
@ront02769 I think I will toss some on just for GP, a 4.6 14 miles away just rudely woke me up :p
 
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