Truss Hole Drilling - Be warned

[TrussMe]

Learn from my mistake. I am in the process of roughing in electrical. Seeing a stout 2x10 bottom chord I didn't think twice that drilling holes for romex would be no issue, right? Wrong.

Reached out to the manufacturer today to 'crunch the numbers' and they will send out for the repair seals. Unsure of the extent of remediation that I'll have to do but figured I'd post. I'll update the thread with what the prescribed fix is.

 

[dcg9381]

Seeing a stout 2x10 bottom chord I didn't think twice that drilling holes for romex would be no issue, right? Wrong.

Did you get flagged on inspection? I know when I was putting plumbing drains in 2x6 framing, I had to look up what was allowed in terms of hole size.

Reached out to the manufacturer today to 'crunch the numbers' and they will send out for the repair seals. Unsure of the extent of remediation that I'll have to do but figured I'd post. I'll update the thread with what the prescribed fix is.

Around here, they just lay the romex on top...

 

[TrussMe]

Did you get flagged on inspection? I know when I was putting plumbing drains in 2x6 framing, I had to look up what was allowed in terms of hole size.

Around here, they just lay the romex on top...

Not flagged by inspection, caught myself. Any discussion with the inspector I wanted to have a plan.

Will be moving the Romex to the top side soon.

Photos didn't attach to the first post:

 

[WisJim]

The truss plans for my shop/garage specified the maximum size and location of any holes added in the bottom chord of the trusses. It did allow small holes in the center in certain parts of the bottom chord, similar to what your photos show.

 

[tarmy]

Not sure why that is a big concern. Many trusses are designed for specific penetrations and in specific locations. Your penetrations are about the only location they should be…not in the tension nor compression areas. They are sorta close to the chord splice where splitting could be induced.

 

[firebirdparts]

Well, yes, but one of the best thing about trusses is that they're all full of holes a washing machine would fit through. It certainly might be a little shorter through the bottom cord, particularly for lights on the first floor, but you don't really need to do all that work.

I am surprised that the manufacturer was concerned, though. And then too I'm surprised the OP asked.

 

[mike93lx]

I am surprised that the manufacturer was concerned, though

Its safest for them to say no, especially when someone is raising it as a concern.

Asking does baffle me a bit, plus doing it in the first place. It's less work to staple it on the chord than drill a hole

 

[TrussMe]

Reading any of the threads regarding drilling holes in trusses resulted in "Not allowed!/Never-ever/Don't even think about it" responses that compelled me to minimally ask. For them to say "no" could be a CYA of some sorts too.

Certainly less work to staple it above, my thought prior was keeping the cable safe from any sort of spare building materials in that area of the truss.

I'll likely discuss my whoops with the inspector prior to performing any remediation work.

 

[mike93lx]

Reading any of the threads regarding drilling holes in trusses resulted in "Not allowed!/Never-ever/Don't even think about it" responses that compelled me to minimally ask. For them to say "no" could be a CYA of some sorts too.

Certainly less work to staple it above, my thought prior was keeping the cable safe from any sort of spare building materials in that area of the truss.

I'll likely discuss my whoops with the inspector prior to performing any remediation work.

The truss manufacturer is the arbiter, not the inspector. They said repair, that's what you need to do, IMO.

 

[gsmith22]

Not sure why that is a big concern. Many trusses are designed for specific penetrations and in specific locations. Your penetrations are about the only location they should be…not in the tension nor compression areas. They are sorta close to the chord splice where splitting could be induced.

its a truss so the entire bottom chord's full depth is in sustained tension in addition to any bending induced by a floor/ceiling. its not a joist in pure bending where you get a compression top and tension bottom. there is no where to penetrate unless the member is specifically designed for it. and generally speaking, metal plate wood trusses are not robustly designed with generous factors of saftey because they are a comodity item.

 

[Hank11]

I caught a newbie electrician drilling for wiring where he could have simply laid the wires on top and saved a lot of work. It seems kinda funny that he did not ask. But I get a lot of “didn’t ask” these days.

 

[Viper98912]

I guess I would've definitely taken the easier way out and stapled it right through that triangular gap...

 

[PopcornSutton]

General rule is mid span-mid depth. Within reason.

 

[mike93lx]

General rule is mid span-mid depth. Within reason.

In a truss? Or a joist?

 

[CraigStu]

its a truss so the entire bottom chord's full depth is in sustained tension in addition to any bending induced by a floor/ceiling. ...

That is a concept I have never come across before. I guess it's good I am not a builder. Thanks for the insight.

 

[Lassen Forge]

I caught a newbie electrician drilling for wiring where he could have simply laid the wires on top and saved a lot of work. It seems kinda funny that he did not ask. But I get a lot of “didn’t ask” these days.

A lot of them decide (or worse, are taught) it's better to ask forgiveness than permission... our **** contractor in Oakland tried that over and over, I caught him every time and forced him to fix his fuc... er... fubars. He started bitching "I'm losing money on this job"... well, pal, if you had done it right the FIRST time and not made stupid "executive decisions" on someone elses house, you wouldn't have lost money.

 

[johninct]

Repairing may not be enough. I had a truss building collapse because of snow. The insurance company engineer looked if I did any type of modification or abuse like a chain hoist before they would pay, just saying.....

 

[mike93lx]

Repairing may not be enough. I had a truss building collapse because of snow. The insurance company engineer looked if I did any type of modification or abuse like a chain hoist before they would pay, just saying.....

If the truss company specs the repair, it should be fine.

 

[Innovate1]

In a wide member like those I wouldn't think some small holes like that would be an issue but the general rule is no holes in trusses (unless specifically allowed). Will be interesting to see what the fix from the truss company is. I had a double truss for a roof gable that sat on top of a wall. It was a tight squeeze to get some wires from the attic to the wall and didn't have any spacing to the drywall to avoid any nails through the wiring. In hindsight I could have run the wire down into a perpendicular wall nearby and gone across the wall and not sure why I didn't just do that. As for going across the top of the trusses many places are going to require a "running board" to tack the wires to - this is to prevent damage to the wires when people walk around in the attic or hit them with material. Not a big deal and easier than drilling all those holes.

 

[TrussMe]

Repair seals provided.

Interestingly enough, no construction adhesive called out, single sided, and scabs can cut for those same holes.

 

[Hank11]

Easy enough fix.