Drilling through Ceiling Joists

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Bama_Electrical

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I was out at a job last week and I noticed that the ceiling joists were drilled for mostly homeruns from one end of the house to the other. I haven’t ever drilled out ceiling joists(unless for a basement or 2 story), normally run the wire on top of the joists in the attic. Are there rules on what is allowed and what is not?
 
The building code (or residential code) has provisions for drilling/notching sawn lumber. If it's an engineered product (glulam or similar) the product will have it's own limitations. You'll want to check your local codes, but it will most likely be this:

"The diameter of holes bored or cut into members shall not exceed one-third the depth of the member. Holes shall not be closer than 2 inches (51 mm) to the top or bottom of the member, or to any other hole located in the member. Where the member is notched, the hole shall not be closer than 2 inches (51 mm) to the notch."
 
tortuga said:
Unless that 'joist' is a engineered truss, learned that the hard way many years ago.
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I always considered a truss as made up of individual components and they always have openings between the components. Usually no need to drill to get through them.
2c28c052f056b359e01cb9ce617b72c1.jpg

An engineered I-joist is a different animal - I never considered them a “truss”.
eb0d696d73e8370597294072cc5e6a40.jpg
 
don_resqcapt19 said:
There are specific requirements as to the size and location of the bored holes, but bored holes are not a "no no".
Click to expand...
I assumed that he assumed that i assumed he meant roof trusses, as he implied a single level home.
Yes, split in thirds top to bottom, and if its a 16" high- the "post" engineer approved spot would be (usually) the top third and the hieght, so 16" from the end..draw a angled line from that point to the top third line.
I wish i could draw it...basically its kinda bad to swiss cheese girders, beams and trusses.
Floor joists, have at it, but make it look good. Prefab floor joists have k.o's anyway.
 
I used to have a good laugh walking other companies or co-workers houses back in my tract days, be it cookie cutter houses or "custom" (yeah, right)
The framers would have a fit! Drill where its easy to hold the hawg, bone heads!
 
the section you are looking for is in the residential code, Sec. 502.8
 

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retirede said:
I always considered a truss as made up of individual components and they always have openings between the components. Usually no need to drill to get through them.
2c28c052f056b359e01cb9ce617b72c1.jpg

An engineered I-joist is a different animal - I never considered them a “truss”.
eb0d696d73e8370597294072cc5e6a40.jpg
Click to expand...
That code section I referenced covers "Structural Composite Lumber" and really any engineered wood product.
The only exception is if the manufacturers instructions say it can be drilled, and where.
These often come with knockout holes.
For example if you are cutting in a remodel box with a hole saw and inadvertently cut a section of the bottom out.
 
tortuga said:
That code section I referenced covers "Structural Composite Lumber" and really any engineered wood product.
The only exception is if the manufacturers instructions say it can be drilled, and where.
These often come with knockout holes.
For example if you are cutting in a remodel box with a hole saw and inadvertently cut a section of the bottom out.
Click to expand...

Yes, absolutely…..I was just wondering if it was correct to call those a “truss.” That would be a new definition of the word to me. Not saying it’s incorrect, it just made me wonder.
 
Joe.B said:
The building code (or residential code) has provisions for drilling/notching sawn lumber. If it's an engineered product (glulam or similar) the product will have it's own limitations. You'll want to check your local codes, but it will most likely be this:

"The diameter of holes bored or cut into members shall not exceed one-third the depth of the member. Holes shall not be closer than 2 inches (51 mm) to the top or bottom of the member, or to any other hole located in the member. Where the member is notched, the hole shall not be closer than 2 inches (51 mm) to the notch."
Click to expand...
Perfect answer. Should have ended the discussion.
 
rambojoe said:
I assumed that he assumed that i assumed he meant roof trusses, as he implied a single level home.
Yes, split in thirds top to bottom, and if its a 16" high- the "post" engineer approved spot would be (usually) the top third and the hieght, so 16" from the end..draw a angled line from that point to the top third line.
I wish i could draw it...basically its kinda bad to swiss cheese girders, beams and trusses.
Floor joists, have at it, but make it look good. Prefab floor joists have k.o's anyway.
Click to expand...
Maybe he did, but he clearly said ceiling joist and the bottom chord of a truss is not a joist. There would be no reason to drill the bottom chord of a truss because, as you say, there are openings that you can run the wiring in.
 
don_resqcapt19 said:
Maybe he did, but he clearly said ceiling joist and the bottom chord of a truss is not a joist. There would be no reason to drill the bottom chord of a truss because, as you say, there are openings that you can run the wiring in.
Click to expand...
I've SEEN idiots do that!! In the garage, single floor house... it knows no end, the dum dums!
Sorry, ill read more carefully...
I'd still say he is speaking of the roof structure, not subfloor..
Final edit... i deduced he called the cat a dog, which happens alot. I enjoy construction CSI..
 
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