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Sources for or Manufacturers of Composite Structural Lumber

idahobuild | Posted in General Questions on

Hey All,

Some of the details that I like, and that have been submitted by members of this forum, suggest using PT or Composite boards where in contact with the slab.  I like the Composite idea but have only found one source (  I knew it would cost more than PT but $1k for 40 feet of 2x is a bit steep.

Does anyone know of another source or manufacturer of this stuff?

Thanks again!

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  1. freyr_design | | #1

    I'm not sure why you would want to use this. You should already be placing a capillary break and if you want it because its perfectly straight you should just use LSL. I'm not even sure this would be allowed by code without an engineer signing off on it.

  2. idahobuild | | #2

    I am thinking of using it in two places.

    1. Vertically installed at each of the garage doors as a thermal break between the concrete that is inside and outside.

    2. Flat under the exterior doors at the thresholds in place of PT. See attached image.

    Also see this thread:

    1. freyr_design | | #3

      Oh I see, so not really structural. With the interior to garage door I would probably just stick with PT and wrap contact with concrete with vycor or something sim. At the garage door not sure.

      1. idahobuild | | #6

        Freyr/All - what about putting Prosoco MVP fluid applied on the edges of the PT lumber that are in contact with the concrete? See Blue on atch'd image.

        1. freyr_design | | #7

          Seems like it would work, I don’t think it needs to be permeable, as you won’t get any drying through it, but it’s not permeable enough to hurt anything.

  3. Expert Member
    Akos | | #4

    Trex, composite 2x6 deck board:

    Can be ordered at my local box store. I would assume other composite deck manufacturers would have something similar.

    You can also use two layers of regular 1" deck board. Try to get stuff with a solid core to avoid any frozen water issues.

    1. idahobuild | | #5

      Thanks! HD is looking for Trex.

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