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I bought some treated 2x4's from Lowes, and it was fairly wet and heavy. I went ahead and built a firewood rack, but screwing into it releases a lot of water. It got me thinking, is it better to let the wood dry out a while before building with it?

This project is done, but if I was going to use treated wood in the future, should I buy some ahead of time and let is sit outside for a few weeks?

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    On a side note. Always use coated, or stainless steel fasteners when working with pressure treated lumber.
    – Tester101
    Jan 25, 2013 at 14:06
  • You should let it sit for like a week. Then the ones that will go all wack, do it before they do it while they're in-situ because they will eventually, and you take it back to the store for a refund. It's always better to have it delivered; they don't put BS on the truck. And the pile you're picking through at the yard is that BS that got sent back on the truck. Just like cashiers feeling fake money, whomever's picking for you at the store can tell when they pick it up, +/- 10% if they're a noob; still only 90% even if they're good, hoping to pass some BS off on you.
    – Mazura
    Jun 1 at 0:49
  • You bought some treated 2x4's from Lowes... and you threw half of the skid on the floor looking for good ones, right? Otherwise, yes.
    – Mazura
    Jun 1 at 0:50

9 Answers 9

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Unless you have a kiln to dry wood in, drying wood in a standard environment takes a really long time (if you buy firewood, usually you want ~2yr old wood!). I don't know that leaving it out for a couple weeks would dry it if it were so saturated that there is visible water coming out of it. It is recommended to let wood used for hardwoods sit a couple weeks to get accustomed to the environment as far as humidity goes, but it is not being dried any further.

I would recommend that you find a better source of wood that is dried properly. You also want to carefully select your wood, it might be that you just got a bad piece some how.

For outdoor projects, instead of PT lumber you might opt to try a wood like cedar which naturally resists the elements pretty well.

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    Redwood is also decay resistant, but if you care about American forests, avoid buying it unless you can verify it was sustainably grown and harvested. I'm not trying to tell anyone what to do, just pointing out there is an issue. Do what you want as long as it is an informed decision.
    – bcworkz
    Jan 26, 2013 at 0:52
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+1 on the stainless fasteners.

TheSean, you're actually working with that pressure-treated lumber in its IDEAL condition for working. After it dries, it'll become much much harder & more prone to splitting. Right now it's very resilient, and every fastener you drive into it "wet" will become tighter as the wood dries out.

Too, dried PT lumber will give you the most painful splinters you'll ever get from any wood. Wet, it's much less likely to give you splinters.

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The answer is simply No.

PT wood will warp if you let it sit. It would have to be in an ultra controlled environment to dry and not warp horribly.

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Wet wood is common when considering the PT stuff. Although not as easy to find, but there is such a thing as KDAT wood (kiln dried after treatment).

You should consider the project and for things that will be exposed to the weather or high humidity, wet wood is OK, just heavy to work with. Two years of drying would only be required if you are building fine furniture, and hopefully you're not using Pressure treated stuff for that.

In building construction, there are times when you want to minimize the shrinkage (primarily in board width) so there are not excessive gaps. My personal experience is that a 2x6 may shrink 3/16" to 1/4" in width, leaving a considerable gap once dried.

If the project under consideration will suffer with that kind of gap, store the wood for a couple of months on a level surface using "stickers" to allow air flow. I have weighted and clamped stacks of wood in attempt to keep the warping to a minimum.

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All PT lumber comes wet. They put it under pressure and force chemicals into it. Then they palletize it tightly so it won't warp in transit and ship it. I usually lay the boards out on a flat surface stacked up in criss cross layers with air space between each board. I put some cinder blocks on top to keep the top layers from warping. In the summer in Oklahoma they dry and shrink n a couple of weeks. I only do this on boards where I care about the appearance. If you put deck boards in wet you are supposed to put them on pushed completely t and then they will shrink about 1/4" in width. However when the shrink they tend to split along the grain where the screws are because the screws won't let the board shrink so it splits instead. If the deck boards do warp before installing you can use a couple of wedges to force them straight but it is a PITA.

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Most likely you got wood that had sat out in the weather and been rained on. Since this is pressure-treated wood it will be fine.

Agreed on using only hot-dipped galvanized or stainless steel fasteners and hardware; the less-toxic chemicals now used for pressure-treating wood are unfortunately more corrosive to metal. Something I've done under e.g. a gate latch that was only electro-galvanized and had rusted in contact with the previous PT gate wood is (1) wire-brushed and painted that side and (2) put a piece of tar paper between the metal and the wood to reduce corrosion. Preferable to avoid trapping moisture next to the metal though, maybe spacers next time.

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  • I don't see an answer to the question here.
    – isherwood
    Jan 20, 2016 at 19:53
  • @isherwood, the answer was "Since this is pressure treated wood it will be fine." Jan 25, 2016 at 19:58
  • Thanks, but "it will be fine" is vague at best. Is that a yes or a no? Please update your answer to clarify, and add your reasons.
    – isherwood
    Jan 25, 2016 at 20:06
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Yes, let it dry. Working with wet treated wood is a very bad idea unless you like shrinkage, cracks, gaps, squeaks, etc. Let your framing and decking dry out first.

Here in Oregon that means buy the wood and store it in a DRY place. Building with wet wood only causes issue later.

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  • This answer goes against most of the other, higher votes answers. I would be weary of this advice.
    – Bort
    Jun 17, 2022 at 18:38
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I buy p t lumber ahead of time, and stack it with spacers in between in my garage. stain will penetrate much better. infact staining can be done before building.Doinng it anyother way, would be like mixing your stain with water.

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Correct me if I’m wrong, I believe “Fine” is to proceed with caution. There are many variables to consider, and I am in agreement. - weather,climate pattern in region - climate conditions when building and being stored - frequency of use for the structural design - longevity - type of wood, quality of wood

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    Hello, and welcome to Stack Exchange. It's hard to understand what you mean; would you edit your question to make it clearer? Thanks. Dec 8, 2018 at 23:13

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