I'm trying to find the building code for drilling or notching in headers under the California building code from 2019 or beyond. I have only been able to find drilling and notching in studs for 2019. Does anybody know where I can find these details for headers?

I want to run some cable through the center of this header. There are no other holes in it.



  • 1
    Through in which direction? What is the header built from?
    – isherwood
    Commented Jan 6, 2023 at 20:51
  • 3
    I don't have any input on whether this is allowed or suitable. But if you end up drilling that hole, drill at a slight angle, such that water or moisture that ends up there for any reason drips out instead of getting trapped or dripping into the garage.
    – nitro2k01
    Commented Jan 7, 2023 at 15:47
  • Built from wood. Not sure what kind though. Direction, straight through. Looking at the interior photo, I would drill from that side.
    – joels
    Commented Jan 7, 2023 at 19:06
  • 1
    @joels Just saying "straight through" doesn't really tell us which way you're wanting to drill. Are you wanting to drill vertically? horizontally from inside to outside? horizontally all the way from the left side to the right side of the garage door? While horizontally from inside to outside is the most likely thing for you to mean, the other interpretations are valid, given what you've said so far.
    – Makyen
    Commented Jan 8, 2023 at 3:05
  • The arrows mark the intended drilling points straight through horizontally.
    – joels
    Commented Jan 9, 2023 at 5:32

4 Answers 4


I'm assuming this is intended to feed a light or camera above the exterior of the garage door.

What I would do is avoid going through the header if at all possible and instead route through the gap above it and come down through the soffit outside.

  • A possible reason to go through the header is it will look nicer. Assuming this is for a light, most fixtures would mount flush to a pancake box with rear entry. If done via the soffit it will need a junction box, probably a 1.5 inch deep outdoor one that is visually quite heavy. Another possible reason is if the soffit is aluminum-clad you don't have to worry about protecting the NM passing through it (probably by just using MC).
    – jay613
    Commented Jan 7, 2023 at 20:14
  • Concur - working on the back of the soffit is awkward but will look better overall. OP needs a light fitting/camera/whatever that has top-entry for cable and it will look neat. OP can add an extra strake of wood above soffit to provide a secure mount for the fitting
    – Criggie
    Commented Jan 8, 2023 at 4:15

I wouldn't worry about a hole for romex in the middle (horizontal and vertical) of the beam. The typical design allowances are 1/3 the depth of the beam and you only need maybe a 5/8" hole for romex. Your 2x10? beam would allow a ~3" hole.

If you create a free account you can get the western wood products notching and boring guide.


  • I'm not sure header beams are sized for such penetrations. They rarely occur.
    – isherwood
    Commented Jan 6, 2023 at 21:07
  • 1
    My engineer allowed a 4" hole in my 20' span double 5.25x11.75 PSL so the toilet drain line could run from the upstairs bathroom to an interior wall in a modern house with very few interior walls. If you have the loading for the beams there is software that will allow you to analyze your hole size and placement. If the beams holding up the top 2 stories with 20'+ spans can take a 4" hole it is unimaginable that you couldn't do a 5/8" hole in the middle of a header for a garage door following the wwpa guidelines. Commented Jan 6, 2023 at 21:20
  • 3
    It really depends on the type of beam, loads, and support. I would agree with Isherwood that we have no idea whether the beam was designed for such penetration. But I also agree with you that a small 5/8 at the very center of the beam could be acceptable.
    – Max
    Commented Jan 6, 2023 at 21:26
  • 3
    In general, drilling through the center part of a uniformly loaded joist/beam/rafter should be fine. In such a scenario, the top part of the joist/beam is in compression, and the bottom is in tension, so there is little stress in the center. This is why I-beams can be made with large holes in them, and is the way trussed members work.
    – SteveSh
    Commented Jan 6, 2023 at 21:51

There is no straightforward answer for this one. It depends on the load the beam/head is getting and whether drilling or boring will reduce the structural capacity of the beam to carry the demand load to the bearing posts.

For a LSL, LVL, or PSL beam, the allowed hole zone is at center of the span where shear is the lowest. The allowed hole zone is not go beyond 1/3 of the length of the beam, centered between the 2 posts and should be centered on the depth as well.

The size of the hole depends on the depth of the beam and whether there are other holes near by. The minimum distance from the next hole is usually 2x the largest hole near by.

As suggested by @Chris O, I would also do everything to avoid drilling the header. That said a small hole for a 12/2 wire may be OK.

Are there any other holes in the beam? Where are they?


Here is information (link) from CA- Los Angeles with clear instructions.


Dated 01-01-2020

LA guide


  • Does this apply to header of just Joist and Rafters?
    – Max
    Commented Jan 6, 2023 at 20:34
  • @Max it is all explained in the document
    – Traveler
    Commented Jan 6, 2023 at 21:12
  • Yep, which is just for Joists and Rafters. Not for headers @Ruskes.
    – Max
    Commented Jan 6, 2023 at 21:29
  • 1
    A header is just a beam - see jwh20 answer for the IBC beam drilling reference. diy.stackexchange.com/questions/203956/… Commented Jan 9, 2023 at 8:02

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