Holes

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guschash

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When drilling through wood joists, what is the largest hole allowed. I always measure joist into 1/3's top, middle , and bottom. I try to drill into middle when possible . I try to stay away from large holes but I seen where electrical contractors drill 2'' holes and pull all their wires through one large hole. It was neatly done but 2'' is a large hole.
 
The International Building Code has language stating the maximum size and spacing for drilled holes in wall studs. The maximum hole size being 60% of the stud width. If the holes are from 40-60% of the stud width, then the stud is supposed to be doubled (and not more than 2 such bored studs in succession). With an exception for using "approved" stud shoes.
That said, a 3.5" stud (2x4) could handle having a 2" hole..... but the hole saw is usually larger O.D. As long as the hole saw O.D is smaller than 2.1" you should be fine.
There are some other exceptions listed here in NC, so you may want to verify with your local jurisdictions in Ohio. For example, if the studs have a minimum 1/2" plywood (or equivalent) attached you can increase the size of the hole to 65%.

I just realized you mentioned joists, so use that info as you will.
As long as you stay in the middle third of the depth of the joists, and OUT of the middle third of the length of the joist and also Not under any bearing points, you are fine
 
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I think it also depends on if it's a load bearing wall. As far as joists are concerned, I was always taught to stay more than 3' from the end and to not take out more than 1/3 and be in the middle 3rd.
 
In the houses I work in I always ask the general contractor and they may ask the engineer where can and cannot be drilled
 
Augie, where is Detail A? I need it to see what the difference is for hole in the first .25 of span vs the .25 to .4 area.

Also interesting that Augie's picture and Wayne's picture show different dimensions and placement of holes! :unsure: No wonder there was a question of size and where.

Engineered joists are different for small holes. Some have pre-indicated spots for holes, hammer knockouts they say, usually does not work. 😄
 
Frank DuVal said:
Also interesting that Augie's picture and Wayne's picture show different dimensions and placement of holes!
Click to expand...
Not sure what Augie's source is, but my reference is to the IRC, which would govern prescriptive requirements if adopted by your jurisdiction. The IBC is similar. I've included the figure from the IRC for those who don't want to click through.


(The IRC and IBC links are to Ohio's version, since the OP is in Ohio. They have a rather old version of the IRC/IBC, but I don't believe the sections have changed.)

Cheers, Wayne

2286eceb-6a54-4de8-be8c-ecaf43a17dfd.jpg
 
My sketch was given to the inspectors by one of our Building Officials. They have since changed to simple notice... no hole closer than 2" from the edge and the diameter no more than 1/3 the width of the stud and holes at least 2" apart but they did not provide any IRC,IBC link
 
wwhitney said:
(The IRC and IBC links are to Ohio's version, since the OP is in Ohio. They have a rather old version of the IRC/IBC, but I don't believe the sections have changed.)
Click to expand...
We use the 2019 RCO. It is based on the 2018 IRC.

Don't forget about 334.15 Exposed Work. Trus Joist and Boise Cascade have downloadable installation guides.
 
Watch out for those attic trusses, the ones that create a storage room, you can't drill any holes in those. Learned that one the hard way.
 
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