Code Allowance for Holes in Joists Bob K

Bob, Could you expand on this comment, please? "personally I think some code allowances for holes in joist are a little too generous."
From your comments, you appear to have run tests. Were the results recorded and conclusions drawn?
T
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From that particular snippet it's unclear whether he means that code allows the holes to be too big, or if it should allow them to be bigger. I'm old school - if you want holes in your joists, use truss joists! ;)
R
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To clarify..... some codes (I did a little researching when the topic came up another time a while back) allow holes that are (IMO) too large & too close together but its just my opinion
It's been a while since I looked at them but it seems that allowed drilling & notching of joists varies a lot from place to place
I recall that one jurisdiction allowed something like multiple 2" hole in a full size (6") 2x6, the separation required was something like only 1" of meat between the holes! .....That didn't seem all that large & the required separation was independent of the hole size which didn't make me feel any better.
Some jurisdictions allowed notches, which is something I would never do without some sort of reinforcement plan.
Sawn lumber isn't a homogeneous material & putting multiple rather large holes in it at questionably close separation doesn't seem like a great idea.
The recent thread about a 2" hole (rather near the end of the joist) in a 8.6" (?) deep joist didn't seem like a big deal......that's pretty much why Robert Allison & I said "don't worry" since that was a pretty big timber & it left a lot more than 2" of meat above & below the hole.
I've be lucky to have had many opportunities to perform & observe tests on timber structures & components. Often if we had a question about how something would perform...we'd just build it & test it.
I have not specially investigated holes in joist but I'm sure research / testing has been done on the topic.and it could be dredged up.
So unfortunately I don't have any hard data to share
I've seen a lot members hacked up (notches & holes; too large, wrongly placed) so I'm not a huge fan of letting the misinformed loose with Hole-Hawgs & Sawzalls.
Hopefully I have enough engineering sense & experience to be able to tell when a hole in a joist is ok & when it isn't.
cheers Bob
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Does this apply to end notches on the top edge as well? Perhaps you could comment on my "Joist Selection" thread. :-)
Cheers, Wayne
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