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:blink: Crap at least it wasn't a water line :thumbup:

Structural yes, load bearing kind of sort of.

The vertical webbing carries the lions share of the load, technically speaking. The bottom and top chords hold the vertical webbing from deflecting under loads.

Call your local lumber yard who carries TJI's and get the skinny on what to do. I know what I'd do and have a good idea what they will say - I'm not a egineer :laughing: so I'm not qualified to recommend anything :whistling Likely not a big deal aka possible easy fix
 

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Discussion Starter · #4 ·
:blink: Crap at least it wasn't a water line :thumbup:

Structural yes, load bearing kind of sort of.

The vertical webbing carries the lions share of the load, technically speaking. The bottom and top chords hold the vertical webbing from deflecting under loads.

Call your local lumber yard who carries TJI's and get the skinny on what to do. I know what I'd do and have a good idea what they will say - I'm not a egineer :laughing: so I'm not qualified to recommend anything :whistling Likely not a big deal aka possible easy fix
I thought it was the opposite, the webbing just keeps the top and bottom chords separate and the bottom chord holds the tensile load and the top compressive. Cut the top or bottom and they are nothing but a 2x3.
 

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I thought it was the opposite, the webbing just keeps the top and bottom chords separate and the bottom chord holds the tensile load and the top compressive. Cut the top or bottom and they are nothing but a 2x3.
That's right, you basically said the same thing he said but twisted the words around. A joist doesn't need a whole lot in the middle, the top and bottom is what's taking most the load. I saw someone do the same thing once, he sawzalled a whole in the floor and took a chunk out of the top chord of a joist, but these were trussed joists. That notch doesn't look like it's big enough to create a problem. Is the notch towards the center of the joist span or is it closer to the beam or wall it sits on? The center of the span is where it needs the most meat on the chord to prevent deflections.
 

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Discussion Starter · #6 ·
That's right, you basically said the same thing he said but twisted the words around. A joist doesn't need a whole lot in the middle, the top and bottom is what's taking most the load. I saw someone do the same thing once, he sawzalled a whole in the floor and took a chunk out of the top chord of a joist, but these were trussed joists. That notch doesn't look like it's big enough to create a problem. Is the notch towards the center of the joist span or is it closer to the beam or wall it sits on? The center of the span is where it needs the most meat on the chord to prevent deflections.
It's near the end of the span, with in the last 4 feet or so. The left speaker hole has half of the chord cut off, right down to the webbing. The other was just slightly notched. I think I would have opted for smaller speakers if I was the original installer. :laughing:
 

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It's near the end of the span, with in the last 4 feet or so. The left speaker hole has half of the chord cut off, right down to the webbing. The other was just slightly notched. I think I would have opted for smaller speakers if I was the original installer. :laughing:
It's probably fine, if it was in the middle of the span with a china cabinet in the room then you might have a problem when someone walks by and says, why is it rattling?
 

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Have no desire to get into pissing matches about what does what...

The webbing is the major load carrying member. Yes there is tension and compression in the chords that adds some to the strength. It's stronger than the sum of it's parts kind of thing.

My understanding and experience is the taller TJI's are stronger with the same relative width/size chords. Similar to an I-beam. That added strength comes form the height of the web- the strongest part of the system.

Guess I could get Oconomowoc (respectfully) about it , but :no: thanks
 

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Have no desire to get into pissing matches about what does what...

The webbing is the major load carrying member. Yes there is tension and compression in the chords that adds some to the strength. It's stronger than the sum of it's parts kind of thing.

My understanding and experience is the taller TJI's are stronger with the same relative width/size chords. Similar to an I-beam. That added strength comes form the height of the web- the strongest part of the system.

Guess I could get Oconomowoc (respectfully) about it , but :no: thanks
No one diagreed with you....
 

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I saw where an idiot plumber notch a girder truss on an addition my buddy was doing the cornice on. It was in the existing part of the house. Always wondered if it failed. Big notch.
 

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Discussion Starter · #11 ·
Have no desire to get into pissing matches about what does what...

The webbing is the major load carrying member. Yes there is tension and compression in the chords that adds some to the strength. It's stronger than the sum of it's parts kind of thing.

My understanding and experience is the taller TJI's are stronger with the same relative width/size chords. Similar to an I-beam. That added strength comes form the height of the web- the strongest part of the system.

Guess I could get Oconomowoc (respectfully) about it , but :no: thanks
I wasn't arguing I just thought they worked like this:



Drawing Diagram Font Art
 

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Take a deep beam of conventional lumber. The top part takes most of the compressive load, and the bottom part takes most of the tensile load. What's in between mainly holds the top and bottom together. Since most of the stuff in the middle doesn't do much, get rid of most of it.

Works with steel, too.
 

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Discussion Starter · #14 ·
Take a deep beam of conventional lumber. The top part takes most of the compressive load, and the bottom part takes most of the tensile load. What's in between mainly holds the top and bottom together. Since most of the stuff in the middle doesn't do much, get rid of most of it.

Works with steel, too.
So the webbing takes the least stress?
 

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Whoa whoa whoa people. You really have to be careful spouting dangerous information about i-joists. I've paid close attention to some detailed conversations with my engineer about this.

In the center of the span, The web does close to 0% and the chords do close to 100%. This is why you can cut a hole chord to chord, only near the center of the span.

At the ends, the chords do close to zero and the web is in strong shear. No holes.

The rub is that the span might not be what you think it is. Non-load bearing walls may be partially bearing, etc.
 

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My understanding and experience is the taller TJI's are stronger with the same relative width/size chords. Similar to an I-beam. That added strength comes form the height of the web- the strongest part of the system.
The reason taller beams are stronger is when the chords are spaced farther, the forces they see are smaller.
 

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Whoa whoa whoa people. You really have to be careful spouting dangerous information about i-joists. I've paid close attention to some detailed conversations with my engineer about this.

In the center of the span, The web does close to 0% and the chords do close to 100%. This is why you can cut a hole chord to chord, only near the center of the span.

At the ends, the chords do close to zero and the web is in strong shear. No holes.

The rub is that the span might not be what you think it is. Non-load bearing walls may be partially bearing, etc.
Hope your are not thinking I spread some dangerous info....

Idiots I am referring to cut out bottom chord & web....

Ain't seen an Engineer yet that would stamp that as cut...:whistling:laughing:
 

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diplomat
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Hope your are not thinking I spread some dangerous info....
Not you. I just hate for someone to read this thread, build something similar, and when it fails say, "but I saw it on Contractor Talk!"

Idiots I am referring to cut out bottom chord & web....

Ain't seen an Engineer yet that would stamp that as cut...:whistling:laughing:
So that exact thing happened to me. Plumber cut out top chord 16" from bearing. Engineer stamped it after I added plywood to the web, and listened to a lengthy explanation of the forces are all shear there, yada yada.
 
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