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Community and Q&A

Does surface wiring on exterior walls make sense with batt insulation?

jamestimmerberg | Posted in General Questions on

I’ve read a lot about the difficulties of properly installing batt insulation. If I kept my plumbing out of exterior walls, and used surface wiring on exterior walls, would that greatly simplify installing rock wool batt insulation? Or, would there still be other obstacles?

If surface wiring would improve the performance of batt insulation, other than the purported aesthetic issues with surface wiring, is there any other reason to oppose its use?

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  1. GBA Editor
    Martin Holladay | | #1

    Surface wiring components cost more.

  2. davidmeiland | | #2

    No one's going to want to look at wiring installed on the surface of the wall. Install it inside the wall as usual, and use the savings to hire someone to dense-pack your walls.

  3. iLikeDirt | | #3

    Mineral wool is easier to install around obstructions than fiberglass is since it's so rigid that you can cut slits or channels in it with a bread knife and easily accommodate wires or pipes in the walls. I don't think it's worth worrying about. Regardless, it's still good practice to keep pressurized plumbing lines out of exterior walls unless you live where it never freezes.

  4. Expert Member

    You can minimize the impact of the wiring by asking your electrician to slightly modify the way they run their services in outside walls. Have them make all their horizontal runs between 6" and 9" from the bottom plate, not just going between boxes at whatever height and angle is most direct. And all the vertical runs should be fastened to the stud faces. Doing it this way means a lot less modified batts and voids.
    Using the same system in your interior walls makes future renovations easier too.

  5. jamestimmerberg | | #5

    Thanks Malcolm.

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