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above ground treated lumber underground

thomh | Posted in General Discussion on October 21, 2008 02:04am

I’ve been called to suggest treatment for a deck built at grade with wide 1/2″ spacing between deck boards to allow for impervious surface rules. The framing below is regular .25 treated framing lumber that’s only rated for above ground use.

However, the lower half of most of the framing is touching the ground. Ironically, I’m doing a similar project and wouldn’t have realized this aspect of the change to treated lumber from 2004 if someone had not brought it up when I was inquiring about material prices.

The soil is very sandy and has extremely good drainage. Does anyone know lof a suitable surface treatment that could be applied in place to help prevent rot and bugs? I would be able to take up several deck boards every so often to get a hose in.

Thanks for your time,

Thom

 

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  1. DanH | Oct 21, 2008 02:25pm | #1

    What "change to treated lumber"? There's always been "ground-contact" and non-ground-contact treated lumber. You never get the former unless you explicitly ask for it.

    Corporation: n. An ingenious device for obtaining individual profit without individual responsibility. --Ambrose Bierce
    1. gfretwell | Oct 21, 2008 03:59pm | #2

      I would still go to a marine supply and get .8 CCA or greater if I was putting something in or on the ground. As long as this is not actually the surface deck your kid can lick, the CCA is not a danger.
      This is just another case of the nanny state, run amok.

      1. frammer52 | Oct 22, 2008 03:35am | #3

        Dan, isn't the standard PT to .40, not .25?

        I have never seen .25 PT.

        Edited 10/21/2008 8:36 pm ET by frammer52

        1. gfretwell | Oct 22, 2008 03:38am | #4

          .25 is that no name green washed stuff at the BORG.

          1. rez | Oct 22, 2008 04:29am | #6

            Today I was at a borg and discovered the bins of what was normally .25 above ground is now having .20 delivered and mixed in with that remaining .25 lumber.

            and no words are being said. 

        2. thomh | Oct 22, 2008 04:26am | #5

          Thanks for all the resposes.

          Our local yard stocks .15 "micronized" here.  Pitiful.  We have to travel to get better stuff and it's still not that great.

          If we time it right, we can get the local pressure treating place to put in a custom order with their big load to get the higher level.

          Here's a link to a 1-800 lawyer who is ready to sue us all. Does anybody know if his statements are any where close to true?  

          http://www.yourlawyer.com/topics/overview/pressure_treated_wood 

          -Thom

        3. MikeSmith | Oct 22, 2008 05:17am | #8

          framer.....
          .25 is the standard for non-ground contact pt.40 is ground contact
          .60 is marine or buried structural.... like "all-wood foundations"or pole-barn polesnaturally....the higher the retention, the higher the costso, better lumber yards stock both .25 & .40and special order .60Mike Hussein Smith Rhode Island : Design / Build / Repair / Restore

  2. MikeSmith | Oct 22, 2008 05:13am | #7

    no..there is no after the fact treatment you can do with ground contact lumber....
    it is going to do what conditions dictate
    it may rot or it may not....but nothing you can apply to it now will make the slightest difference

    not unless you continue to apply it on an ongoing basis..from now until death you part

    Mike Hussein Smith Rhode Island : Design / Build / Repair / Restore

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