I am wanting to install an attic fan over the gable vent and had a couple questions.

  1. There is a 2x4 running through the center of the vent. Can I cut this in the middle so it doesn’t block the fan? I will be mounting the fan on a plywood frame attached to the studs next to the vent.
  2. The fan comes with a 15’ cord but the attic outlet is maybe 25, away. Can I simply use an extension cord or do I need to tap into the attic lights and run wire to the fan location?

The side studs are 51” apart and the opening is 10”x15”. I was planning on putting a 17” fan over top.

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Thanks for the advice!

  • Using a extension cord for a mounted fan would be agents code, the proper thing to do would be to extend the circuit from the existing bod and put a new box / receptacle in.
    – Ed Beal
    Mar 12, 2021 at 19:58
  • As apposed to an attic fan, what you probably need most is more ventilation in the attic. Ensure your eaves are properly vented. Most attics don't have enough ventilation in them. Aug 10, 2021 at 19:53

1 Answer 1


Yes, you can cut enough of the vertical 2x4 to install your vent fan.

Because 1) The 2x4 is “flat” against the gable end wall and is only used for nailing the sheathing (and presumably the siding) 2) there is no ridge beam, 3) spacing of the 2x4’s is 51” so the gable end wall is not structural.

If the “wall” seems a bit wobbly at the vent after you remove a portion over the vent opening, you could add horizontal stiffeners above and below the vent opening from adjacent 2x4’s.

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