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Thread: Question about concrete around a treated post

  1. #1

    Question about concrete around a treated post

    Hi.

    Does anyone know if the new treated lumber 4x4 posts can be encased in concrete? I am going to have a new side porch built and I don't know whether it would be best to have it free standing or to drive 4x4 treated posts into the ground . If I put the posts in the ground , will the new chemicals used to treat the posts affect the concrete in any way if posts are encased in concrete?

    Thanks,

    Bob

  2. #2
    Join Date
    Feb 2004
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    Clermont County, OH
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    No expert here:

    Most of the decks in my area have a footer poured. The treated post then rests/attaches to this footer. I would think that you would have some serious issues ahead of you were you to sink the post into the concreate and then you have some rotting of the post.......???

  3. #3
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    Nov 2003
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    Cecil Wisconsin (near Green Bay)
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    Bob,
    The usual way to do it is to pour a concrete footer and use a metal clip attached to the footer with an anchor bolt. The 4x4 is then bolted to the clip with a gap between the bottom of the 4x4 and the top of the footer. This keeps the wood from resting on the concrete and wicking moisture from the concrete.

    Dean

  4. #4
    You really shouldn't encase the posts in concrete for many reasons. First the post will absorb all the moisture out of the concrete. Second the wood will, overtime, take what is called a compression set and cause a crack which will let all the bad things happen to wood that makes it rot quickly. Posts should be held above the ground and above the concrete with brackets or saddles. This allows for air flow that will keep it as dry a possible. If you must bury the posts...for rigidity and strength...fill the hole with stone so it can be compacted and will drain.
    Glenn Clabo
    Michigan

  5. #5
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    Mar 2003
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    I'm with Donnie. Pour footers, and embed Simpson post anchors in the top of each one. After the concrete cures, you put your posts into the post anchors. There's no worries about wood rotting in the ground, and no path for termites. It is also easier to get your posts to line up. When you put a post in a hole and fill the hole with concrete, the concrete may move the post. In contrast, you can place the post anchor after you've put the concrete in the hole, and you can put the anchor exactly where you want.

  6. #6
    Join Date
    Mar 2003
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    SE PA - Central Bucks County
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    Further...putting the posts on footings with the appropriate hardware means you can easily replace said post in the future if need be. If it's in concrete...mucho work.

  7. #7
    Join Date
    Dec 2003
    Location
    Snoqualmie Wa
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    If you are going to put the posts into the ground, it is best to place 3-4" of gravel at the base. Then pack gravel around the post. This will keep the water away from the post itself. Even the pressure treated will eventually go bad if immersed in water.

  8. #8
    Join Date
    Dec 2003
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    I built a fence for some friends several years ago using Redwood (plentiful around here! ). After digging the hole for the 4x4, I put several inches of pea gravel (or something similar) in the bottom of the hole and worked the 4x4 into it a little bit before pouring concrete. That was 8 years ago and so far, so good. I think I would do it differnetly now....

    However, I think it is quite ugly seeing that metal fastener (if you can see it) holding up the 4x4 post even if it the right thing to do.

    I had a new fence put in 2 years ago and what I had them do was to put in a small knee wall of cinder-block (maybe 1' high) and then put in columns of cinder-block spaced at 8' intervals and then put in redwood panels between the columns. My redwood fence panels will never touch dirt and will last a very, very long time. Finally, I had the cinder-blocked veneered with flagstone.
    Attached Images Attached Images
    Wood: a fickle medium....

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  9. #9
    Join Date
    Mar 2003
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    Quote Originally Posted by Chris Padilla
    However, I think it is quite ugly seeing that metal fastener (if you can see it) holding up the 4x4 post even if it the right thing to do.
    The brackets can be painted/stained to match or you can put a wood "collar" around the base to dress things up. That construction should be made to allow water to roll off and should not touch the concrete. In some localities, the brackets are required for posts...the wood isn't allowed in the ground for structural applications. (Fences, obviously, are a different situation)

  10. #10
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    N Illinois
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    Footers better

    Footers w a bracket are the better solution. Many years ago, I helped my Dad repair some fence posts that were burried in cement (pre Pressure Treated Posts) and they virtually snapped off. It was a difficult repair job. Had to dig out the old cement collar (Ugh) Its best to keep the post high and dry above the ground and cement! And footers for safety should go below frost line.
    Jerry

  11. #11
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    Yeah, I did dig out all the old 4x4s w/attached concrete...will NOT do that again! Hey, post #3000....
    Wood: a fickle medium....

    Did you know SMC is user supported? Please help.

  12. #12
    Join Date
    Jul 2004
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    DFW, Tx
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    I live in the Pacnorwest area the land of rotting wood and Most of the fence posts are treated 4x4 in concrete usually about 30" deep, I did mine the same way but if I were doing a deck I would use footers with simpson hardware just for the ease fo repair and adjusting.
    Larry

  13. #13

    Question Another question.

    While we are at it. Heres one I'll throw out here. Not to hijack your post Larry.

    If building a deck and setting pressure treated posts in the ground surrounded by concrete is a no-no, [First I have heard of this being a no-no] then what about a pole building [which is what I have] that is basically the same thing. 6x6 treated posts set 3' deep surrounded in concrete.
    These types of buildings are all over the country and have been for a long time. I have not heard of any falling down due to treated posts failing.

    Curious Steve


  14. #14
    Join Date
    Apr 2004
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    If you are concerned about the look of the metal bracket, then box in the base of the post with 1x4 or 1x6 pressure treated lumber.

    Dan
    A flute without holes, is not a flute. A donut without a hole, is a Danish.

  15. #15
    Has anyone ever seen a wooden power pole set in concrete?

    I have never had to replace a fence post set in packed dirt, stone, and sand, but I have replaced many set in concrete (including a few I did myself in my youth).

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