Drilling holes in trusses

matt_mMay 19, 2008

First of all, I would never do this. I've heard of contractors drilling holes in the outer 2/3's of trusses, for running wire in the floor space of useable attics, and leaving the middle third alone, but it sure seems to me that a hole drilled through a truss in ANY location could seriously compromise the integrity of the truss.

I'm posting this because I have a nosey, "unhelpful" neighbor who keeps coming around, wanting to help me with my addition (2x4 trusses), and when he saw me running 12/3 wire along the face of the trusses, and stapling them every couple of feet, he asked why I didn't just drill holes through the dang trusses and stick the wire through them. I sure would like to hear yalls opinions on this. Seems like a no-brainer to me, but I've been wrong many, many times before.

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Give this a read. It pretty much says that you have to have 4" of lumber plus the hole diameter to drill in a framing member.

And, drilling trusses is usually frowned on anyway reguardless of lumber size. In your case with 2X4 stock you're short of being able to drill a hole anyway because of the 2" minimum from each edge (2X4 being 3½")

    Bookmark   May 20, 2008 at 1:00AM
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you should not drill through the trusses. I nailed 2x4's on top of the trusses to act as cable runs, and stapled the wires to the tops of these boards OR ran the wries along the sides of the trusses.

I did violate the rule of no holes in 2 floor trusses but I got permission first. They were small enough holes that they did not degrade the load bearing characterstics of the trusses.

    Bookmark   May 20, 2008 at 8:18AM
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