I dug holes for four 8' 4x4 posts, and had the posts positioned and plumbed vertically in the holes, but had to leave for a couple days before I could concrete them in.

In the meantime, storms came and filled the holes. The ends of the posts have been sitting in that water now for 2 days. Are the posts ruined? I've thought about flipping them over to be sure, but if they're done for, no problem, I can use them for other stuff if I have to.


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    What sort of pressure treatment? Above ground use only or ground contact? Commented May 2, 2019 at 19:17
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    Doesn't really matter over a few days.
    – isherwood
    Commented May 2, 2019 at 19:53
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    @KevinMcKenzie, ground contact Commented May 2, 2019 at 20:45
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    Unasked followon - all you need to do now is let the rainwater drain away, and make sure there's no muck dropped into the bottom of the hole, If you have room a trowel should be enough to get by the post without re-truing it. Then once its dried out enough get on with the concrete.
    – Criggie
    Commented May 3, 2019 at 0:41
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    Concrete absorbs water too. Its presence won't protect wood from moisture over the long term. That's why the posts have to be treated to survive (or could be some species of naturally decay-resistant wood). Commented May 3, 2019 at 17:44

2 Answers 2


Pressure treated wood can handle submersion. Many folks just pack rock around the post, so they are always in water after rain. You should be fine to go ahead and pour your concrete with no worries.

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    Remembering, of course to provide open drainage at the bottom of the concrete rather than a cloced 'bucket'. Commented May 3, 2019 at 9:10
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    @SeanHoulihane Why? Submersion in water doesn't cause posts to rot - it's exposure to water and air. A rotted post will be rotten six inches to a foot (150mm-300mm) either side of ground level, and fine outside that range. Commented May 3, 2019 at 12:00
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    diy.stackexchange.com/a/246/54122 Commented May 3, 2019 at 12:53

Pressure-treated lumber is pressure-treated by... wait for it... submersion. It was literally dunked in a vat of liquid. The vat was sealed and pressurized, forcing the liquid to enter the wood. It was then not kiln dried.

Your lumber is in roughly the same condition it was in when you purchased it. Also, it would have been just as wet even if there had been soil (or concrete) in the hole along with it.

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    No wonder it's so dang heavy!! :-) Commented May 2, 2019 at 19:31
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    I assume you are correct in your final verdict, but arguing that wood treatment involving submersion in some undisclosed liquid means submersion in water of the final product is fine is a bad argument. I can easily make things with submersion in any number of liquids as a part of the manufacturing process that cant handle submersion in water upon completion.
    – Matt
    Commented May 3, 2019 at 3:26
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    @Matt True in principle, but "Usually, water solutions of preservative salts are employed with this process" (even though oils are possible). Commented May 3, 2019 at 12:08
  • For example, Matt? Since wood isn't "manufactured" in a strict sense, that argument isn't worth much. Its properties are pretty well known.
    – isherwood
    Commented May 3, 2019 at 12:44
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    @isherwood Wood isnt manufactured, but pressure treated boards certainly are manufactured, which is what we are discussing. Examples of manufactured products with liquid submersion as a step that dont work well long-term in water upon completion include any quenched metal blades, most electronics, and many foods.
    – Matt
    Commented May 3, 2019 at 15:18

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