What's the MAX diameter hole can be drill on beam?
- Thread starter xirix
- Start date
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Beams are a whole category unto themselves and engineers are who we get help from on that. Because it depends on the loads of the particular situation.
I've see solutions using plywood and shear nailing, steel plates bolted, added sandwich framing.
Never bore a large hold in a structural beam without clearance from an engineer.
I've see solutions using plywood and shear nailing, steel plates bolted, added sandwich framing.
Never bore a large hold in a structural beam without clearance from an engineer.
2018 IPC - 5th Version November 2021
Arctic trouble
Well-Known Member
Do you mean beam or floor joist? It appears you mentioned both. Each manufacturer has charts for hole placement and are very very specific but it's seems fairly common for beams to do center 1/3 of span and center 3rd of depth and is usually no more than 1" bored under 9" beam and no more than 2" on beams up to 18" (bored hole saw cuts only not notched or square cut). If you are the sub ok it with the homeowner or gc first or you might be on the hook to repair.
Mitchell-DIY-Guy
Well-Known Member
I have seen a number of new homes under construction (including one yesterday) where the holes for flexible ductwork basically span the entire OSB web (space between the dimensional lumber top and bottom) of an engineered floor joist.
I’m not a jurisdictional code inspector nor engineer but I never like seeing these.
[My own preference is metal ductwork within interior wall cavities, and insulated metal if needed such as in an attic. The use of all this flimsy flexible ductwork has either allowed or caused ductwork to become a complex, sloppy mess in new construction.]
I’m not a jurisdictional code inspector nor engineer but I never like seeing these.
[My own preference is metal ductwork within interior wall cavities, and insulated metal if needed such as in an attic. The use of all this flimsy flexible ductwork has either allowed or caused ductwork to become a complex, sloppy mess in new construction.]
Apparently xirix edited his post, because now he is just asking about floor joists. The IPC code I listed above covers plumbing holes in joists and studs.
We have a few contractors on a sister site called
Www.houserepairtalk.com who may be able to ask specific contractor questions.
Www.houserepairtalk.com who may be able to ask specific contractor questions.
Joist Boring:
2x6 = 1 ½”
2x8 = 2 3/8”
2x10 = 3 1/8”
2x12 = 3 ½”
As the code quote states: nothing within the top and bottom two inches
2x6 = 1 ½”
2x8 = 2 3/8”
2x10 = 3 1/8”
2x12 = 3 ½”
As the code quote states: nothing within the top and bottom two inches
Make sure that the holes are bored at the center of the joist or beam.
Mitchell-DIY-Guy
Well-Known Member
Here's what I was talking about in new construction here in NC. These were taken in the same house, a 2021 build. The flexible ductwork snakes its way through engineered ceiling joists, and note that the hole cut pretty much spans the entire "web" (the OSB) part of the joist. These were in two areas of the same house, on the first floor, looking at the ceiling joists. Home on a slab, so all the HVAC is in the attic.
Attachments
Actually, that large of a hole in and engineered I-joist is acceptable, depending on its location in the run of the I-joist. In college, one of my structural professors asked us what the web of an I-beam was for. His answer was to keep the flanges apart. The same pretty much goes for engineered I-joists. The flanges, the dimensional lumber part of the I-joist, is where the strength is provided. The top is in compression, the bottom is in tension, except where they are cantilevered, and there is very little strength provided by the OBS part of the I-joist.
However, the parts of the I-joist close to a support point, as is shown in your second picture, is a huge problem. Manufacturers have certain criteria that must be met, and one big one is that no holes are to be located near a bearing zone. It looks like your pictures shows the hole actually extending over the bearing lumber that has been toenailed into the bottom of the I-joist. Large holes must be located in the middle part of a span, and they cannot be close to each other. Even if that is not an actual load bearing wall, it is providing a bearing point, and that hole should not be located there. It needs to be moved away from that bearing zone by the manufacture's requirements, which is at least 12" between the edge of the hole and support point, and probably more. This is what happens when construction workers see things done and repeat them without knowing the parameters that must be met.
Mitchell-DIY-Guy
Well-Known Member
From what I've seen, in the structural framing of a home, very little thought is given to what comes next--i.e. the plumbing, the HVAC guys, etc. It would be nice if all the HVAC folks did a Manual J/Manual D on each home, and the plumbing was all done by licensed masters. However that never happens. The worker-bees come in and cut whatever the heck they need with little regard for either the structure (as shown with the large holes cut near the bearing points) or the next guy coming in behind him. Everyone at the "builder" seems to be too busy to properly check on the subs.
...and that's why you see the stuff as shown above.
