# Pressure treated posts set in concrete?



## AtlanticWBConst.

zubin6220 said:


> I had a pole barn built several years ago and noticed that the 6x6 posts were not set in concrete. I inquired, and was told that it would void the warranty. Is this true that pressure treated posts should not be in concrete?
> I've seen other applications in which they were indeed put in concrete.
> Thanks in advance.


The answer is really subject to opinion. 

(The key is that you NEVER want to install a PT post into an area that can create "standing Water" around the post, as this will break-down (water-log) the resistance treatment of the wood and eventually allow it to decay.)

Regarding your question; I've seen it done by reputable and experienced GC's. However, we choose not to place decking posts into concrete. Rather, attaching the post with brackets and mechanical fastenings to the surface of concrete piers or footings. Aside from my opinion, see below for other's....



*Read up on the opinions:*

http://www.sawmillcreek.org/showthread.php?t=12478&page=2

_"Pressure-treated pine posts are ideal for fencing because they resist rotting. These posts can be set in concrete to ensure their stability. Many companies offer an extended warranty on their pressure-treated posts to guarantee their quality." - _http://www.americanfenceassociation.com/consumerfence/wood/index.aspx


_"Should all posts be set in concrete?_
_We recommend that all posts be set in concrete in accordance with local conditions and standard building practices. Posts that are not set in concrete will eventually lean due to wind and weather. Check your local building codes through your city or county government for further details." - _http://www.millsteadinfo.com/faq.aspx

_"The post can be placed atop a concrete pier, bolted to a steel anchor, or it can be set in the concrete. Placing the post into the concrete pier adds strength, but it is more susceptible to rot." - _http://canada.contractors.com/trade/wood_fence_install.html

_"Posts that weren't properly treated or set in concrete typically rot away at ground level." -_ http://home.howstuffworks.com/how-to-repair-a-wood-fence.htm

_"Why are we so concerned about longevity of this treated lumber post? Because treated lumber does not last forever. I have seen treated lumber begin to decay after less than 20 years of exposure to the elements. Anything that can be done to reduce the amount of water next to the post will surely reduce the chances of the preservative being washed away." - _http://www.hammerzone.com/archives/decks/oldporch/found/footing.htm

_"_Question: _Is it ok to put a deck post into concrete instead of using an anchor, and if so,will the post not last as long as using an anchor.frost level is 36", how much of the post should be buried in the concrete.will this way be stronger(less sway) than using an anchor. thanks _
Answer: _Hi Ray. Definitely better to put it in concrete. Should give you minimal sway depending on how high the post is above the ground or deck. I am not too sure about frost levels as my life in the U.S. has been spent in California, Florida and south east Georgia. 24" depth into the ground should be quite O.K. Hope this helps."_ - http://en.allexperts.com/q/Decks-3464/deck-support.htm


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## KUIPORNG

Great information Atlantic...


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## concretemasonry

If you don't set the post in concrete for a fence, it will have much less lateral reisistance and can lean.

For a deck, few bolted attachments provide the lateral resistance that you really need in the long term (wood shrinkage, vibration and bolts loosening). If the deck is not too high, you may get away without embedding them. If the deck is higher, you will need some lateral bracing (diagonals (ful or just at the post/beam connection) to prevent swaying.

When ever you embed treated wood in concrete, keep the concrete 2" above the ground and form a sloping concrete/mortar cap to shed the water. This will help make the post last much longer.

Treated wood can do quite well when it is moist (like in concrete). What really eats up the wood quickly is the alternate wetting and drying you get from the soil at ground level. If you ever look at the old posts on ocean piers, the wood is fine below water level and above, but rots near the water line where the tides cause wetting and drying.


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## RYANINMICHIGAN

no crete is code in MI


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## murray59

A pole barn or pole shed gets its strength from the poles being sunk into the ground. That's why they are so economical, they don't require any footings. As for puting cement down the hole, well packed soil is just as good a cement. As was mentioned earlier you have to make sure there is good drainage so water can't rot the wood.


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## AtlanticWBConst.

zubin6220 said:


> I had a pole barn built several years ago and noticed that the 6x6 posts were not set in concrete. I inquired, and was told that it would void the warranty. Is this true that pressure treated posts should not be in concrete?
> I've seen other applications in which they were indeed put in concrete.
> Thanks in advance.


As stated, Pole barns in general, do not require their posts to be set in concrete. 

You mentioned:


zubin6220 said:


> _"_I inquired, and was told that it would void the warranty.._."_


Did you mean that you inquired with the *company* or *business* who constructed the barn? .......... or that you simply "_asked around_" and got that answer from others?

In Terms of this question:


zubin6220 said:


> Is this true that pressure treated posts should not be in concrete?


 The answer to that question is all together different from the context of your inquiry pertaining specifically to _Pole Barns_ and _Pole Sheds...._


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## feloneouscat

murray59 said:


> A pole barn or pole shed gets its strength from the poles being sunk into the ground. That's why they are so economical, they don't require any footings. As for puting cement down the hole, well packed soil is just as good a cement. As was mentioned earlier you have to make sure there is good drainage so water can't rot the wood.


Around here (Austin, Texas) poles are sunk in concrete. I've got one 10 year old pole barn and one 6 year old pole barn that are doing fine. I've got sand (literally) and it doesn't seem to pack well...

Cheers,

Feloneous


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## the roofing god

here in new york ,we typically secure posts to the footing w/brackets,also the pressure treated post will shrink slightly as it dries which will cause some loosening


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## feloneouscat

the roofing god said:


> here in new york ,we typically secure posts to the footing w/brackets,also the pressure treated post will shrink slightly as it dries which will cause some loosening


Yah, but if you sink them four feet, even with 'crete the shrink is virtually non-existent. What little there is gets filled in with dirt (our horses are messy about that).

Tho' to be fair, I had to pull one of our fence posts (also sunk with 'crete') and the sucker popped out like a cork. As always, your milage may vary...


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## tractorman90

*post set in concrete*

I built a pole barn and put gravel in around the post then cement. So it should be all right since the building is on a slop with good drainage and it going to be close in, with lean too on it and concrete floor. water should not be around any of the main post very much. i haven't built lean too yet but when i do i wont put cement around the post.


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## titanoman

When imbedded, the concrete shall be sloped...away...from the post. You know why.


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## tractorman90

*post in concrete*

That to help shed the water away from post. here is a ideal i had to help prevent rot. If u drill thew small hole in cement around the post and time to time squirted some motor oil in them that would help i think. But i probably would only do that in a in close building. other wise water would get in the holes as well. Any thoughts, thanks.


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## pyper

zubin6220 said:


> I had a pole barn built several years ago and noticed that the 6x6 posts were not set in concrete. I inquired, and was told that it would void the warranty.



Only way to know for sure is to read the warranty.

The two I looked up both exclude wood used as a foundation, specifically excluding "poles". The warranty is nearly useless anyway. It only covers the cost of replacement timbers, not the cost of doing the replacement.

I put mine in concrete -- it keeps the termites away, which seems greatest risk around here.


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## Missouri Bound

Pressure treated wood will eventually rot in concrete....not nearly as quickly as untreated, but it WILL eventually. And any structures lateral strength comes from proper construction, not inserting the support members in concrete....fences and utility poles aren't structues.


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## PoleBarnGuru

*Pressure Treated Wood Against Concrete*

In Chapter 23 of the IBC (International Building Code) specifies the use of preservative-treated wood when in contact with concrete. 

I've been searching for any authoritative study which would back up the tales of concrete causing preservative-treated wood to decay.

Anyone who has testing results which would lend credence to the apparent old-wive's tale of concrete decaying preservative-treated wood, please share them with me.

Your assistance is appreciated.


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## Daniel Holzman

I have inspected some 20 odd houses damaged by hurricane flooding that were supported on wooden piles. Some of the piles were directly embedded in sand, some were embedded in concrete, and some were driven into the ground and packed around with gravel or crushed stone.

The only thing the houses had in common was that the house above the piles had sustained massive damage from flooding. In a few cases, part or most of the foundation had been washed away as well, although in most cases the foundation was intact, while the house was mostly destroyed. I would post pictures, which are really pretty interesting, however it would violate my contractual agreement with the companies I worked for, so unfortunately I cannot.

I can say that the wooden piles exposed to salt water were damaged primarily in the tidal zone, and the majority of damage was from marine insects. The dry zone above the high water line was generally in excellent condition, even for untreated timber piles that were 50 or more years old. In many cases, portions of the piles well below the normal sand line were exposed due to loss of shoreline, and the originally buried portions of the piles were in generally good condition. The portion of the pile subject to wetting and drying was always the worst, and in many cases there was 50 percent loss of section. In a few cases, I wondered how the house even stood.

Based on my inspections, and literature I have reviewed, I have come to the belief that treated or untreated wood performs very well if it is kept either completely dry, or is constantly saturated, either with fresh or salt water. I have inspected numerous dams built on untreated wooden piles that are over a hundred years old, and in several cases we cored the wood, and the conclusion is the same. If the wood is always wet or always dry, it performs very well. If it is subject to alternate wetting and drying, it rots relatively quickly.

I have heard all sorts of stories purporting to have evidence that embedding wood in concrete causes the wood to rot quickly. I have never personally seen any evidence of this, and like PoleBarnGuru, I would very much like to see a well developed report on this topic. I believe that the portion of the pile just above the ground is likely to be the most at risk for rot, hence must be the best protected, whether by use of waterproofing agents, or perhaps wrapping in fiberglass or similar material.

Several houses I inspected which had severe foundation damage were being rebuilt, using precast, prestressed concrete piles, which can be driven directly into the ground, and provide outstanding resistance to rot. A few houses were being rebuilt using steel piles, which also can be directly driven, and will last a very long time under normal service conditions. There is still a thriving wood pile industry, as wood is less expensive than either concrete or steel, and not every building needs to last a hundred years or more.


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## Rockerga

*Overkill.....*

Lifetime..._or close_ guarantee for imbedded posts.

I wrap the post in 25# roofing felt. I cut a piece to fit the bottom and staple it solidly closed, then I wrap over that all the way up the post for the length the post will be buried - Stapling completely, then heat the seams with a torch. (Basically wrap it like a present! )

I set the post and pour the concrete topping it off in a decorative slope to make all water run-off and away form the wood.

I have never been able to test my applications past 18 years to-date but at this writing they are like I did them yesterday!

I do keep a coat of oil based paint on the areas I can reach, re-painting as required. (18 years and only the second coat of paint)


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## mjvdet13

quick side bar question here instead of making an entire new thread. Im sinking one 4x6 PT post tomorrow that will be part of a 7' (tall) fence and will be using concrete... Does the 1/3 rule apply to 4x6s as well or should I go down a bit further? I was told to be safe and just sink it 4'... any input?

Thanks ahead of time

EDIT*** Also, one end of the fence will be butting up against my brick home. Do I want it to butt right up against or leave a.... lets say 4"-6" clearance away from the building?


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## Rockerga

mjvdet13 said:


> quick side bar question here instead of making an entire new thread. Im sinking one 4x6 PT post tomorrow that will be part of a 7' (tall) fence and will be using concrete... Does the 1/3 rule apply to 4x6s as well or should I go down a bit further? I was told to be safe and just sink it 4'... any input?
> 
> Thanks ahead of time
> 
> EDIT*** Also, one end of the fence will be butting up against my brick home. Do I want it to butt right up against or leave a.... lets say 4"-6" clearance away from the building?


I would sink it below the frost line and be done with it. With that said Mr. Overkill here would use an 80# bag of concrete per hole also....

If you buy 10' 4 X 6 and your frost line is less than 3' you are good to go, otherwise you need to go to 12' lumber and that also adds a lot to your overall cost.

Butting the house or not: Butt the house, which also keeps out (or in) creatures. Butting the house also allows you to attach to the house creating a strength member. (Bolting a 4 X 6 to the house!)


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