So my dad came over today to do electrical but I didn't realize he was going to drill holes into the load bearing beam to route cables.

It looks like this and there's 2 of them:

The diameter of the hole is 1 inch.

enter image description here

One in a 14ftx6in beam and another in a shorter beam I'm guessing 6ftx6in.

Is this okay or should I somehow fix them? I read that you can use epoxy glue to fill the holes?


  • Is the pic of hole and beam the one in question? If so there is a wall under the drilled hole which may not be load bearing but it helps. The problem I see is that the hole is much bigger than needed and too close to the edge of the beam. Otherwise a 3/4" to 1" drilled hole, an 1 1/2" or more from the edge for wires is good ALMOST anywhere in the beam. Stay out of the middle third of the span. – Jack Jul 9 '17 at 22:19
  • Hi Jack, yeah that's the one in question. It was drilled horizontal and then vertically. The wall is a frame we added underneath 2x4 frame. The hole is 1 inch in diameter and located at the edge unfortunately. Do you think this is fine? I'm considering removing the cables and filling the holes in if possible. – Andrew Ma Jul 9 '17 at 22:38
  • Yikes, that's a fair bit of material to remove on the edge of the beam between both those holes... I'm a little concerned someone drilled those big of holes into a load bearing beam without realizing it could be done much better is doing your electrical work... – enderland Jul 9 '17 at 22:46
  • Yeah I don't know what I should do moving forward any idea if there's a decent fix to this? I don't mind removing all the wiring. – Andrew Ma Jul 9 '17 at 23:26
  • 1
    Removing the wiring and filling the holes would not restore the load bearing rating of these beams (unless the area where the holes were drilled was in pure compression which these areas do not appear to be). There appears to be a very large safety factor in the sizing of these beams. I don't think there is a risk, but I am not a structural engineer. Don't do anything hasty. Consult an engineer. – Jim Stewart Jul 9 '17 at 23:52

I wouldn't be taking you father-in-laws key from him or you'll find yourself outside sleeping with the dog.

I think I understand all your dimensions and explanations. Very good...except I want to clarify two things: A.) The 260" long beam runs PARALLEL to the 160" long beam, but they are NOT side by side. That is to say, they're separated by 10' or so, and B.) When you say the 330" and 264" long joists are PARALLEL, you mean PERPENDICULAR.

If so to BOTH those issues, then the following applies and you can still let you father-in-law help with the remodel.

1) These are older style glue-laminated beams. (Beams now are 5 1/8" wide.) These beams are fairly "beefy" which indicate they are holding up a significant part of your house. In fact, they are size appropriately to hold up 2 stories.

2) With the holes, their size has essentially been reduced to 5 1/4" wide x 10 1/2" high. (I'm guessing all the holes are drilled up from the bottom about the same distance.)

3) The maximum load on the beams, (this means when all your friends come over for your daughter's birthday party and stand on the beam,) is about 1,000 lbs. per foot.

4) The 60" beam will support a gazillion pounds plus a car. No worry.

5) The 160" long beam will barely support 950 lbs. per foot, depending on the sources of wood, etc. (I don't know where this is located...I doubt Kenya.) However, the good news is that is a lot of support and I wouldn't worry about being 50 lbs. off the MAXIMUM allowable load for that beam.

6) The 260" long beam has some problems. We calculate beams for bending, shear and deflection. This beam can support about 350 lbs. per foot, about 600 lbs. per foot and about 250 lbs. per foot. Not so good.

Now, the good news: beams fail by cracking over time or bend and allow walls setting on / near the beam to settle and crack. So, we can monitor the area over this beam and see if cracks develop in the walls above the beam or the beam starts to crack. (You probably won't see the beam start to crack, because this failure is going to be "horizontal shear". Which means cracks will be horizontal in the beam and be disguised by the grain.) But you will see cracks in the walls above the beams until they become unsightly. Beams are designed to fail in tension first...not in compression, which would fail with an explosion...that's the good news.

Houses are grossly over designed (here in the states). Depending on where the hole is drilled (how far in from the end of the beam) it may not matter...much. If you want, let me know 1) where the hole is located along the beam, 2) species of beam, (or if you don't know let me know where the house is located,) and 3) keep all waterbeds and parties over 100 off this beam.

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  • Comments are not for extended discussion; this conversation has been moved to chat. – Niall C. Jul 13 '17 at 3:31

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