Truss-joists

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JES2727

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I have a question regarding the TJI truss joists used in newer homes. You know the stuff, it looks like 1/2" particle board or "chip board" with heavier wood running along the edges. A customer is finishing his basement. He'll be putting in a sheet-rock ceiling rather than a hung ceiling. This means that all of my wires need to be run through the joists, and the existing wires that are stapled along the para-lam beam will need to be relocated to run through the joists rather than taking the shortcut below them. Question #1 : Can I notch the bottom of these joists rather than cutting the cables and finding some creative places to spot some j-boxes? Also, several walls have been framed out running the length of some of these joists, and the only way for me to get my wires down them is to drill through the top plate and the bottom part of the joist. Question #2: Is it acceptable to drill through these joists? I know this is not an NEC issue, more of a building code issue. But I figured some of you guys with more experience than myself in residential wiring may have come across this sort of situation before. ( I'm more of a commercial/industrial type of guy)
Thanks.

John
 
Re: Truss-joists

JES, you absolutely can not drill the trusses, ever. Don't do it. You have to find another way. Sorry.
 
Re: Truss-joists

check the trus joist web site, you can drill thru the web of the TJI's staying within the manufactures recommendations, what is trickier is the parralam beams or heavy structural wood....www.trusjoist.com
 
Re: Truss-joists

Originally posted by sparky_magoo:
JES, you absolutely can not drill the trusses, ever. Don't do it. You have to find another way. Sorry.
Click to expand...
That is not true. According to this web site

www.trusjoist.com/PDFFiles/2035.pdf

they give you locations, sizes, and distance between for holes 4" or greater. For holes 1.5" and smaller can be drilled just about anywhere except for in the hatched zone.
 
Re: Truss-joists

As the others have stated. TJM is very specific about the do / don't of drilling the joist.

What I do is scab the bottom w/ 1X or 2X material running perpendicular to the joists. Yes it is more work and expense, but it makes wiring so much easier.

Joe
 
Re: Truss-joists

You can drill the webbing of the TJI's but the flanges you can't. The link that was put up shows you where you can drill the webbing. Keep in mind that there are many manufacturers of these products and each will have their own requirements.

A gluelam or microlam are engineered products, so you have to get engineering approval to drill holes in them.

Chris
 
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