Drilling Vertical Hole in supported joist


Old 08-19-18, 08:15 AM
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Drilling Vertical Hole in supported joist

I know that drilling vertical holes in joists compromises them, but I am hoping that it would be okay in my case because this joist will still be supported by a parallel wall that runs beneath it. My alternate wire paths are much more difficult, and my first floor is concrete.

To run 2 ethernet wires, I want to drill a 1/2 hole from my 2nd floor wall down into my 1st floor stairwell wall. Everything is enclosed and painted, but I am presuming that there is a double joist above the stairwell wall.

Based on work in another room, I know which way my joists run, that they are 9" high, and that my studs are 24" on center.

Because the stairwell wall is 12' 2" wide with a 2.5" doorway, it supports the joist everywhere except the doorway, and I will be drilling in the supported section.

Is it okay to drill the vertical hole through the joist because the stairwell wall will continue to support the load despite the joist hole?

I've attached a drawing.

Thank you in advance for your help.
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Old 08-19-18, 08:37 AM
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Drilling up through the joist is ok since its supported by a wall. However if the wall is ever removed it becomes a problem because along a stairway those joists often act as a beam. (Before the interior walls are built).

You would be better off drilling two separate holes that are as small as possible... say 1/4". Or with careful measuring you might actually be drilling between the 2 joists.. barely notching the sides of each one.
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