drilling joists

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fisbn

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decatur ,ga by way of boston,mass
Had a discussion with a guy I am doing a job with.I have always gone by the 1/3rd (rule) when drilling joists(you have to come out 1/3rd the distance of the joist to drill holes),I swear i was made to do it years ago,he just drills holes everywich way and has never had a problem.I know it looks a lot neater my way,but does anyone else know what i'm talking about?
thanks
Larry
 
fisbn said:
Had a discussion with a guy I am doing a job with.I have always gone by the 1/3rd (rule) when drilling joists(you have to come out 1/3rd the distance of the joist to drill holes),I swear i was made to do it years ago,he just drills holes everywich way and has never had a problem.I know it looks a lot neater my way,but does anyone else know what i'm talking about?
thanks
Larry
Click to expand...

If you are drilling 7/8" holes you can drill anywhere. It depends on the size of the joist and the size of the hole. If you are drilling 2" holes in a 2x8 you may have some problems. I;ll see if I can find that info.
 
it has been my understanding that you cannot be in the inner third of a span, and must be within the inner third of the of the joist vertically, and the diam. cannot exceed 1/3 the witdth of the joist
 
The maximum size a bored hole can be in a floor joist is no greater than D/6 where "D" equals the depth of the floor joist.

Also, hole boring must be confined to the first third from the bearing ends only and there shall be no bores in the middle 1/3 or any floor joist.

Where "L" equals the length of the joist, L/3 is the maximum distance from each bearing end in which bores can be permitted.

IRC 2003 Codes sections cited: R502.8 and Figure R502.8

FWIW 1/6 vert and 1/3 horiz
 
billsnuff said:
Also, hole boring must be confined to the first third from the bearing ends only and there shall be no bores in the middle 1/3 or any floor joist.
Click to expand...
I don't agree that holes can't be drilled in the center 1/3 of a joist. Notches aren't allowed in the center 1/3. R502.8.1 & figure R502.8. If you drill in the center 1/3 of the length, then I believe it must be within the center 1/3 of the depth. Again, figure R503.8. This is for dimensional lumber only. Engineered I-joists have there own set of rules.
 
rcarrol

rcarrol

i agree, depending on the method of construction and materials used, other rules apply. I was speaking to dimensional lumber and should have said that, thanks for pointing it out. :cool:
 
drillingjoists1.gif
 
billsnuff said:
The maximum size a bored hole can be in a floor joist is no greater than D/6 where "D" equals the depth of the floor joist.

Also, hole boring must be confined to the first third from the bearing ends only and there shall be no bores in the middle 1/3 or any floor joist.

Where "L" equals the length of the joist, L/3 is the maximum distance from each bearing end in which bores can be permitted.

IRC 2003 Codes sections cited: R502.8 and Figure R502.8

FWIW 1/6 vert and 1/3 horiz
Click to expand...
Thats always been my understanding untill I was helping a friend the other day and he asked me to route my cables a longer way around because he said you can not drill any beam that is laminated, Ive never heard this rule and I thought he was wrong( well nuts to say the least) Does anyone know what he is taling about????
 
tonyou812 said:
Thats always been my understanding untill I was helping a friend the other day and he asked me to route my cables a longer way around because he said you can not drill any beam that is laminated, Ive never heard this rule and I thought he was wrong( well nuts to say the least) Does anyone know what he is taling about????
Click to expand...

Some load-bearing beams cannot be drilled at all. Lam beams are one.
 
480sparky said:
Some load-bearing beams cannot be drilled at all. Lam beams are one.
Click to expand...

For any kind of engineered lumber, the manufacturer's
instructions will provide this information.

For example, the ilevel lam beams on page 4 of:
http://www.ilevel.com/literature/TJ-9001.pdf

are the most common in my area and can
indeed be drilled.

There is no "rule" as in stick lumber, it's what the
manufacturer says.
 
Sparkyrob11 said:
You can drill microlam... D middle 1/3, L middle 1/3
Click to expand...

This is true for the engineered lumber I work with. There
is also additional space in the length where you can do
some drilling, so it can be >1/3.

You also have to follow instructions wrt the size of the holes.

What you really have to do is look at the manufacturer's
instructions for the specific engineered lumber, because
it will vary by manufacturer.

There is another thread currently with a title of something like
"what's wrong with the other trades?"
http://forums.mikeholt.com/showthread.php?t=99928
This is making me wonder if there was a framer's forum
somewhere with a bunch of posts like "What's wrong with
those Electricians (and Plumbers)?". Nahhh, couldn't be.
 
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That's true, but with the microlam, lvl, I have yet to see something spec'd contrary to the middle 3rd x middle 3rd rule...but it is always a good idea to double check what you're up against. I've heard it's a pain to change out beams after rough structure is complete:wink:
 
Sparkyrob11 said:
That's true, but with the microlam, lvl, I have yet to see something spec'd contrary to the middle 3rd x middle 3rd rule...but it is always a good idea to double check what you're up against. I've heard it's a pain to change out beams after rough structure is complete:wink:
Click to expand...

Good point. Better to be safe than sorry, and it is
a good practice to not push the envelope on this
type of issue.
 
I see a lot of jobs with beams stacked right under every stinkin wall in the residence... fun, fun. Why can't everything be done in concrete?
 
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