Pole Barn Post

These pictures are of a normal lumber yard 4x4 pressure treated post that was put into a hole and backfilled with the clay dirt from the hole. No concrete was used. As you can see it has rotted out and not at the soil level. It rotted out down deep in the hole. No sign of termites. Was a deep ditch about 3 feet away from this post that did not hold any water so the soil around the post should not have held any water.

So after seeing these pictures can someone tell me one more time why anyone would use wooden post buried into dirt for something as critical as a building foundation such as in a pole barn.
It's a fact of life. Dirt holds water and water and wood do not mix even when pressure treated. Sooner or later the wood will rot out.

And for the person that will surely come along and say "That's why you use something like concrete perma post"; I have to question the lateral wind load integrity of a post that is spliced together when the walls are 10+ feet tall and post spacing of 10 feet.


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Depends on the wood and how it's treated pulled post out that have been in the ground since the 50 ' s and still solid. Pulled post out that has been in since the 90 ' s and was rotten like yours. Tossed a broken one from the 50 ' s on the fire plenty of creosote dripping out. Also different states different regulations I buy post out of iowa there better treated than the ones from Wisconsin.
 
You can get treated wood that was poorly done. I've heard some places just hose the wood down with the chemical to give it the green color. I have a building built in the 1980's with treated posts and a storm destroyed the building but left the posts. I dug them up and broke the concrete off of them and re-used them. The posts didn't deteriorate at all being in the ground.
 
Well, nothing is forever. I used iron pipe in concrete & kept the concrete up the post above ground level, & the pipe rusted out by 20 years. So what is a feller to do?
 
Not all treated wood is for ground contact but if it is the wood below ground will last longer than that above. First to go on good treated posts is at ground level,not below.
 
John it makes a big difference in what retention level of wood was used. CCA retention levels were .25 for above-ground use and .40 for ground contact. So if non ground contact wood was buried then it would rot fairly fast.

So it is the right level of treatment for ground contact that makes all the difference.

I moved a "pole" building that was built in 1978. The posts looked like new. I looked at another one to move last year that was built in 2000 and all the post where rotted below grade. Different materials.
 
Concrete footings with wood fastened to the top above the ground is always going to be a better way to go than a post put into a hole. Why did your post rot where it did? Probly because the very bottom of the post stayed wet for the most part, and closer to the surface of the ground it stayed dry for the most part. But the area where it rotted was dry half the time, and wet the other half inhanceing the rot in that area. Given enough time, the entire portion of the post below ground would of rotted as well. As others have said, it probly wasn't adequately treated for in ground use to begin with. But even if it was, wood in the ground is not going to last forever.
 
I seriously doubt that post was rated for ground contact.

As for whether a post set on concrete footing can handle the wind load, how is that different than a 2x4 wall attached to a concrete foundation? The ability of a post frame building to resist wind loads isn't dependent so much on the bending moment of the posts as it is on the wall bracing. The building is a box structure, and if properly braced the wind loads are transmitted throughout the structure. The posts primarily serve to support the weight of the building, which is why it's important to put concrete at the bottom of the post holes to support that weight.
 
The post was rated for

UC4A

Wood and wood-based materials used in contact with the ground, fresh water,
or other situations favorable to deterioration.
SERVICE CONDITIONS:
Ground contact or fresh water, non-critical components
USE ENVIRONMENT:
For normal ground contact or fresh water contact
Exposed to all weather cycles
COMMON AGENTS OF DETERIORATION:
Decay fungi and insects
TYPICAL APPLICATIONS:
Fence posts, deck posts, structural lumber & timbers, guardrail posts,
utility poles in regions of low decay potential
 
Set the post on a piece of concrete & backfill the hole with rock.
Be sure to put anti-uplift blocks on the bottom of the posts.
 
Yea, as I figured, it's not really to bury for a building support. Not treated well enough.

As well, a lot of stuff from the 1980s or so was poor, even with the sticker it was just bad. They were better before and after the 80s.

Everything wears out eventually. Cost vs useful life..... If the posts last 300 y arms, well the tin won't....

Dad put in a small (by today's standards) shed in the early 60s, poi Ed concrete stem, home sawed wood on top 2 foot spacing. The stem wall is cracked in a few places, it will shift out eventually..... The lumber is like new, but the tin is going away on me. Another 20 years and it might be time to do something? Everything wears out....

A well treated laminated post, with the bottom pieces treated, the top pieces not, seems to be about the best cost vs useful deal right now. Can't find a 6x6 post of good wood any more, fast growth wood of today twists, has knots, you need the post built up from 2x8 or 2x6. The pressure treatment gets in better on a 2x as well.

Paul
 
I imagine it depends on soil and climate too. In our area there are pole sheds 50 and 60 years old with no rotting problems. Very rare to even see concrete pore around the posts up here.
 
Here"s a pole building we moved from the second farm in 1998....Originally built in the 60s. IIRC it"s 36x75 feet. Hyd jacks lift it up- mover does not cut off posts.
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Moving down the road- had REA trucks to hook/unhook wires, but only one bothered, so lineman got on shed roof, picked it up, and walked it off the back end. One day to lift, one day to transport and set into new holes. $4500 for the move.
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So it was SUPPOSED to be treated for ground contact. Clearly the treatment wasn't properly done. It appears to have rotted from the inside out, evidence that the treatment didn't make it to the center of the post. Of course there's no good way to tell if a post has been properly treated, and I've cut the end off more than one 4x4 to find the treatment only penetrated part way into the post. The best you can do is to stick with a reliable supplier.
 
Around here I like to use hedge posts when I build a small shed. We have plenty here and they last forever. They will sprout if they haven't been cut for at least a year.

My big sheds are laminated posts. They are still standing. I wonder if that's better just because those 2x12's have a better chance of chemicals to the center.
 
in all my designs for treatment on cca in ground contact i specified 1.0 retention--allsalt water contact i specified 2.5 retention--nothing beats creosote for lonevity
 
CCA .40 and .60 typically last a long time depending on soil conditions, same with utility poles, but both are highly restricted now. I don't recall what they use for marine applications, I would suspect the concentration of preservative is even greater. You can order CCA treated lumber for agricultural and industrial purposes, if one was to use posts set into the ground, CCA does work well. Soil conditions, water table and or site drainage will also be factors to consider.

Ideally, concrete is best, and those perma posts, if spliced properly, I can't see how you could not make a connection to insure the wind loading you want is achieved as you can do a lot with concrete and steel. Maybe its a custom design to make that happen, or you just have to go with a more conventional foundation design and building which will increase costs substantially.
 
John,
I've had a similar problem with a treated 4x4 from lumber yard in contact with the dirt for 15 years.

However 25 years I paid to have privacy fence put up. They used the same 4x4's and put them in concrete. Some say concrete isn't a good thing, but I've don't agree.
geo
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