Freshly cut white oak tree as a support post in the chicken run

[Sunshine Flock]

I'm adding a rain shelter to the chicken run that will extend out from the back of the coop. There are two oak trees inside the run, so I wasn't sure I'd be able to dig a hole for a post to support the 72" overhang.

But much to my surprise I easily dug a 31" hole. All of the eight foot fence posts were sunk about 27" into the ground. With this one I just kept on digging, since I'm going to cut down a white oak from our property (wider than a 4x4) and use it as the post. Lots of people have used white oak for fencing and say it can last for decades. I don't use cement and instead packed rock into the holes. With this one I'm going to use old gravel and the clay I dug up today.

My question has to do with the bark. Green posts aren't a problem; they don't need to cure. But to peel off the bark should I wait until it begins to dry and loosen on its own? I read that autumn trees tend to have really tight bark that's hard to peel and that it's best to wait until spring and summer.

Also, what about the bark below ground level? Since there isn't any oxygen down there, I would think the bark won't post any problems. I'd like some feedback on this, though.

Thank you!!

 

[tigger19687]

I think the bark is easy to remove when green/alive. You need a good knife to cut lines down (top to bottom) and then just peel.

FYI, all this knowledge is from watching TV, like live free off the land, diy stuff.... so take with a grain of salt.
But I would take the bark off the part that goes underground anyway. If you leave it, it rots, then the post may not stay as tight ??

 

[Folly's place]

Oak will rot in damp soil, probably before you want to loose it! It will work better above ground.
Mary

 

[Sunshine Flock]

I've been reading for years now that lots of old time ranchers prefer white oak for fence posts. Some of their relatives have said that posts installed 40 years ago are still standing. Below the ground there isn't any air. It's where the soil line at ground level meets the post that rot happens.

I think peeling the log now is a good idea. I don't have any knives to do this. I'm wondering what kind I'll need.

 

[cavemanrich]

I know you try to avoid chemicals and such as much as possible. Is roofing tar included?
Long ago before all the pressure treated lumber became popular/common, fence posts , and other things going into ground (or contacting ground) were coated with liquid roofing tar. (at least by some in my area) The tar was only up to a little above ground level. It kept the wood from being eaten by ground insects as well as it seemed to prevent rotting from wetness. I used pallet lumber (not pressure treated or tar coated) as a landscape alternative, and it did not last very long. The pressure treated edging/landscape logs lasts much longer, although not forever.
I have tried using plastic pipes filled with concrete. They last , but are not very attractive and more difficult to attach things to unless well planned fasteners are installed ahead of time. (before filling with concrete).

 

[squadleader]

I was reading a technical article about pressure treating processes this week, I know, most people prefer spy novels as light reading, I'm a little different, I'm afraid useful information is my cup of tea.

So the point being, for rot you have to have four things, rot fungi (it's always present), oxygen, food, and moisture above a certain percent in the wood.

All rot prevention revolves around removing at least one of those items.

Pressure treatment actually invades the cellulose of the soft wood (the treatment doesn't penetrate the heart wood usually, it's too dense) and poisons the cellulose as a food supply to the rot fungus, it's not poisonous to us.

The interesting take away from that, at least for me, is treated boards are much better protected than post material like 4x4, 6x6 and so forth because they contain the more vulnerable heart wood. The boards are much more likely to contain only soft outer wood that took the treatment well.

Ok, the work around to that vulnerability, is picking posts that are still encapsulated in the outer soft wood, which took the treatment well, and actually protects the mostly untreated heart wood. Meaning, examine post wood you buy, look at the ends, is the heart wood still fully surrounded by the soft wood, which protects the heart wood.

You're obviously not pressure treating, you've got to have a good field treatment, so your strategy is depriving the always present fungi of oxygen, and also keeping the moisture content as low as possible in the wood.

I love rock around posts, but if there's no ground water present around the post, but are the voids around rock (the voids make rock great for draining off water, like in a French drain) allowing in oxygen? Terrific but probably impractical solution is a post hole full of gravel, that daylights on a down side slope.

On the other hand, a post hole that's always submerged in ground water, will not allow oxygen, so no rotting.

That being said, our rivers in Virginia are full of hundred year old pilings that have zero rot below the low tide mark, but are completely rotted off above that, because at that point, oxygen and high moisture allowed the rot.

The solution in your case, in my opinion, is exactly what Cavemanrich pointed out (way more succinctly than me), coat the post up several inches above the ground surface.

Your observation that most rot occurs at ground level is spot on, it's just like the pilings in the river, the ground level is many times damper and wetter than a post up in the air. The ground and the first several inches of the top soil are likely always damp, and any rain, snow or dew, constantly wets it.

In coating the post, don't forget the bottom. Coating up past the ground, will keep the moisture content down, and discourage rot. Will the rocks in the backfill puncture the coating, I don't know. Would clay backfill deprive the post of oxygen better, I don't know.

You're only concerned it sounds like, with a few posts, so if preserving their integrity for a long time is important, it's not to hard to do these extra measures.

One last thing, the article mentioned, which I had never heard before, that there's common surface treatments at places like Home Depot, that you're actually supposed to apply to the cut ends of pressure treated wood when you cut it, I never knew that.

I always over do everything, I can't help it, so you'd see me out there, first applying that surface treatment from Home Depot, then slathering on Cavemanrich's roofing tar! A hundred years after I'm dead, somebody will walk up to the post and say "after all this time, how the hell is this thing still in such good shape, that's great, but in the meantime, I'm still dead, so why I get carried away with all this stuff is beyond me!

Here's a great easy to read step-by-step that answers all your questions, that I just stumbled on.

http://homeguides.sfgate.com/protect-wooden-fence-posts-rotting-47852.html

Everything else below is in regard to the technical article.

The article specifically mentions the brush on chemicals of copper naphenate or compounds containing tributyltinoxide or polyphase as an effective surface treatment in the field for do it yourselfers like us.

Apparently those chemicals are commonly available, hopefully at Home Depot, but ordering off the web I'm sure. Probably a brand name product, where you'd have to check its ingredient list.

To quote the article:

"Unfortunately, treated wood must often be cut or bored after treatment. In order to protect the untreated wood, a grease containing 10% penta is often applied. The grease provides a protective long lasting coating that can be slowly absorbed into the wood. Grease treatments are also used as remedial measures when untreated wood is placed in areas of high decay hazard. Brush-on solutions of penta or creosote are also used by those possessing a license to apply pesticides. However, do-it-yourselfers are encouraged to treat freshly cut preservative treated wood with copper naphenate or compounds containing tributyltinoxide or polyphase."

Here's a link to the entire article:

https://www.extension.umn.edu/garden/yard-garden/landscaping/selecting-preservative-treated-wood/

While all this is dry reading, let's face it, we go to a lot of time and effort to build stuff. I want every advantage I can find when it comes to avoiding rot, so all my hard work isn't wasted. So all this stuff interests me a great deal!