# Maximum diameter holes in 2x4 interior walls.



## DangerMouse (Jul 17, 2008)

I need to run plumbing through a 2x4 wall for 5' or so, am I OK drilling a 2" hole through them to allow room for foam noodles as well as the tubes?

Thanks!

DM


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## jarleifvaagen (Aug 20, 2010)

1 3/8" in single 2x4 stud, and 2" if studs are doubled if i remember correctly..


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## jarleifvaagen (Aug 20, 2010)

i think you need 5/8" to the edge from the hole, and the hole can't exceed 40% of stud depth in single 2x4, 50% in doubled 2x4..


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## Mr Chips (Mar 23, 2008)

jarleifvaagen said:


> i think you need 5/8" to the edge from the hole, and the hole can't exceed 40% of stud depth in single 2x4, 50% in doubled 2x4..


I always thought you could go larger if stud was on non load-bearing wall.


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## jarleifvaagen (Aug 20, 2010)

that's very possible..I would check with local building codes to be sure..I base my information from one of my mentors which may or may not be correct on the issue.. 

if you take a 2" hole out of a 3,5" stud, there's not a whole lot left on either side..if you then offset the hole a little by accident it'll be even less on the one side... I cringe every time i put a 3/4" hole through a 2x4... lol...then again i tend to overdo things... one of my favorite terms while building something is "This should hold an elephant!".. haha


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## DangerMouse (Jul 17, 2008)

There will be a wooden wall on one side (back of tub) if that makes a difference. Drywall on the other side should be sufficient?

DM


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## Gary in WA (Mar 11, 2009)

http://docs.google.com/viewer?a=v&q...JXyMiv&sig=AHIEtbThg1pHd54AM8EHb6CBPjc714bhbA

Ask locally also...

Be safe, Gary


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## Willie T (Jan 29, 2009)

This is kind of old. It’s an excerpt from the _1994 Uniform Building Code, _the International Conference of Building Officials. But I think the numbers are still the same today. 

*Sec. 2326.11.10. Bored Holes.* A hole not greater in diameter than 40 percent of the stud width may be bored in any wood stud. Bored holes not greater than 60 percent of the width of the stud are permitted in nonbearing partitions or in any wall where each bored stud is doubled, provided not more than two successive doubled studs are so bored. 

This drawing shows 2x6 walls, but you can apply the math to 2x4's if you need to. (A 2x4 is about 63.64 % of a 2x6...... Multiply any number shown here by *.*6364, and you should be in safe territory.) That means the 2.25" hole shown in the upper righthand example would convert to a hole 1.4319 in a 2x4. That's a little less than 1-7/16".)

But if you are going for the 60% number, you're safe with 2.1..... or a light 2-1/8". (That's a 2" hole wallowed out a tiny bit.)

Of course all this is assuming the code is still the same today as it was way back then. And if you have a stickler for an inspector, it never hurts to drill a slightly smaller hole than actually allowed. Gary shows newer and tighter codes, so I wouldn't push it.


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## DangerMouse (Jul 17, 2008)

Thanks! That's very helpful! I figure I already drilled the holes, so if the framing inspector has a problem, I can always add 2x4s sideways centered in-between the existing studs, alternating edges front to back, and just keep what I have. I should probably just do that anyways since I'm pretty sure he'll say something.....

DM


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## DangerMouse (Jul 17, 2008)

Something like this should be accepted if the holes are too big, yes?

Thanks!

DM


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## jklingel (Dec 21, 2008)

(I guess I nuked my last reply, so....) Looks like you had room to hang the tubes from the 2x4s, no? The "sideways" 2x4 may do more good if it is snugged against the "normal, holy(play on words there, guys)" one and nailed. Each can brace the other against deflection in their weak direction. Gary?


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## DangerMouse (Jul 17, 2008)

Good idea....

DM


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