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I just added LVL to both sides of the carrying beam in my basement which was overloaded due to a 2nd story added. The original built-up beam was three 2x8 nailed together. It was completely covered with 17 or so NM cables for half its length. I pulled the staples and tie-wrapped them to the bottom of the joists until the LVL was added.

Now I have to put the wires somewhere. I ordered some Arlington CableWay (an overhead raceway) which looks very neat from pictures. This will go on the bottom on the joists to half the length of the house and stop at my stairs which are attached to the beam at its midpoint.

I have 3 NM for the furnace, AC, and other that continued on past the stairs on the old beam. The raceway is pretty expensive and I figured I wouldn't continue the raceway for 3 cables. Even if I wanted to, the stairs are in the way and originally these 3 cables were run low on the beam under the attachment cleats for the stairs (a very narrow area) and then out the other side of the stairs where they shifted to a high point on the beam for the rest of the run.

Now for the question: What's the opinion for stapling NM on LVL beams?? I ask because a friend told me about a case where stamped attachment plates with array of sharp points weakened the LVL. Of course this is a lot of "nails" in a small area as compared to stapling 3 cables. But it made me think of the other half of the beam that had 17 cables stapled to it. If I didn't order the raceway, it would mean driving a lot of staples into the new LVL.

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Don't worry about staples in a beam. (These are beams that can have 3/4" holes bored in them -- at appropriate sizes/spacings, of course -- so a puncture would mean nothing.)

I suspect your friend's story was more about the holding power of the plate than weakening the LVL.

(edited to remove "substantial" and replace with 3/4" -- thanks SP)

  • LVL beams certainly CANNOT have substantial holes cut in them. You are thinking of TJI I-beam type joists. LVL's have very restrictive boring and drilling rules. – Speedy Petey Nov 26 '15 at 16:52
  • Poor choice of words on my part -- in this context, substantial was 3/4". I'll edit my answer. – Aloysius Defenestrate Nov 26 '15 at 17:05
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    LOL, yeah, 3/4" is hardly substantial. I thought you mean like 6" square. – Speedy Petey Nov 26 '15 at 17:06
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you can put a thousand staples in it. if your LVL is appropriately sized, attached and supported, electrical staples won't do any harm. if you are worried about it, just keep the staples randomly distributed and towards the top of the beam (compression loaded) instead of the bottom of the beam (tension loaded).

  • Okay, thanks for the reply. I actually used twice as much LVL as a Structural Engineer specified which was one on one side. I moved my electrical panel and had my water heater exhaust moved to get a 2nd LVL on the other side of the beam as well. I had custom 1/2 inch top plates 8 inch wide made to support the new beam (was 4.5 wide, now 8 wide). I also put 1/2 inch bolts staggered every 16 inch instead of 24. – PJD Nov 27 '15 at 0:26

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