# Pole Barn question



## Dan Rogers (Jun 29, 2008)

I'm putting up a pole barn that has 6x6 pressure treated posts.  I live in South Florida and my soil is very moist and I've read where some people coat the bottom of their posts with roofing tar to provide additional rot protection.  Has anyone done this and is it worth it?  I assume the tar wouldn't have any reaction/problem with the concrete.


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## jdgator (Jun 29, 2008)

I don't think you want to put the untreated wood in concrete... Seems like all that locked-in moisture would rot the wood. I would go to your local hardware and ask what they recommend.


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## Doyle (Jun 29, 2008)

I've never heard of doing that.  You can buy various grades of PT posts.   The stuff sold at Home Depot/Lowes will either be "above ground" or "ground contact".  If you go to the lumber yard, you can get "subsurface grade" or "marine".   The marine stuff is pretty expensive.  The stuff made for subsurface has more of the preservative stuff (used to be CCA but I think that has been phased out).


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## debo (Jun 29, 2008)

I've heard of it to.  But it seems if the post wick's moisture it would act like a bucket and not let the water out and rot the post eventually.  I built a polebarn about 6 years ago and just concreted around the post but a buddy of mine builds houses and he said that is fine.  But of course i am not living in Flordia with your soil.Good luck with the Hurricanes i would say that would be your worst problem.


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## Dan Rogers (Jun 29, 2008)

My barn came as a kit so that I could meet the hurricane code and get a permit.  The plans call for a 4' hole, 12" in diameter, with 30" of concrete below the fill line, so I don't have any choice but to use concrete.  

A neighbor just had a 20 some year old barn torn down due to rotted posts which had also been in concrete and that got me to wondering what else I could do to help avoid a problem down the road.


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## bany (Jun 29, 2008)

i may be nuts,but i think putting a decent amount of concrete in first then the pole ,and then fill above the grade a little and angle the concrete you would have a good set-up. don't like the tar idea  much but there is a copper base solution you might use as extra protection.


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## jimbo4116 (Jun 30, 2008)

bany said:


> i may be nuts,but i think putting a decent amount of concrete in first then the pole ,and then fill above the grade a little and angle the concrete you would have a good set-up. don't like the tar idea  much but there is a copper base solution you might use as extra protection.



You want the bottom of the pole to be exposed.  The pole will act like a wick.  Moisture from rain and he like will exit the pole from the bottom.  

Place the post in the hole, stabilize in position with a little soil, pour concrete around post. Be sure to mound the concrete so water will run away from the post.

PT lumber is rated by the preservative per lb. per cubic foot of lumber.  You want a rating of 40 or better.  You can further treat by soaking the ends in coppertox.

PT will eventullay decay, check with the manufacter for specs and guarantees.  

But don't waterproof the bottom end of you posts, if anything water proof the exposed area.


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## tuffdawg (Jun 30, 2008)

Why dont you just bolt the post to the top of the concrete? Think the brackets range from $8-10 a piece at home depot. Just as sturdy as cementing them. 

When you concrete them in, the few years downt he road, when you have to replace them, you have to cut them off even with the concrete. Then you have an ugly  hole there.


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## tuffdawg (Jun 30, 2008)

Dan Rogers said:


> My barn came as a kit so that I could meet the hurricane code and get a permit.  The plans call for a 4' hole, 12" in diameter, with 30" of concrete below the fill line, so I don't have any choice but to use concrete.
> 
> A neighbor just had a 20 some year old barn torn down due to rotted posts which had also been in concrete and that got me to wondering what else I could do to help avoid a problem down the road.




NEVERMIND, just caught this one. sorry.


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## ranger1977 (Jun 30, 2008)

Dan, do the hurricane resistant codes mandate that the post be encased in concrete?  The reason I ask is because simpson strong tie makes several anchors for post to concrete connection where you install the anchor while the concrete is being poured in.  The top of the anchor is exposed and after the concrete cures, you can connect the post to the anchor. These connections have several thousand lbs. of uplift resistance. The post is insulated from the ground and the concrete so you really never have to worry about moisture.  Just wondering.


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## j_seph (Jun 30, 2008)

Contact these guys and you could probally get more info on preventing/delaying rot
www.ybc.com/


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## hunter_58 (Jun 30, 2008)

Dan Rogers said:


> My barn came as a kit so that I could meet the hurricane code and get a permit.  The plans call for a 4' hole, 12" in diameter, with 30" of concrete below the fill line, so I don't have any choice but to use concrete.
> 
> A neighbor just had a 20 some year old barn torn down due to rotted posts which had also been in concrete and that got me to wondering what else I could do to help avoid a problem down the road.



If you have a kit, do you know what kind of PT you have? most 6x6s are min. ground contact treated.    your's should be rated for below grade, if it came as a kit, with footing  directions as you described.
Simpson ties will hold down barn, but wont take lateral load.

check the treated rating, if checks out place as directed.
BTW,  if your barn came as you stated, it should be stamped by an engineer licensed to business in your state


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## bany (Jul 1, 2008)

i notice alot of treated wood with ground contact and a decent amount of age that seems to be perpetually wet and it's not rotten.other areas where it get's to dry out then wet and so on is rotted.that's in north Ga. and that's what lead me to that thought. i do believe the key in any case is you can't treat the stuff too much with the proper stuff.


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## MudDucker (Jul 1, 2008)

One reason that "pole" barns" are so popular is that they used to be built out of "telephone poles".  Those poles were treated to the max with perservatives starting with creosote in the old days.  I pulled up an old utility pole at my farm last year and there was NO rot whatsoever.  That pole had been in the ground more than 40 years.  None of the modern preservatives are that great, but telephone poles are still treated to the maximum.  Yes, I've seen the bottom of poles treated with tar.  Don't know if it really helps long term, but it would seem that it would have to by stopping some moisture.

With today's wood and treatment techniques, I would agree with those who suggest not sinking the post into the wood, but instead use a steel tie in method for above ground installation.


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## dawg2 (Jul 1, 2008)

Dan Rogers said:


> My barn came as a kit so that I could meet the hurricane code and get a permit.  The plans call for a 4' hole, 12" in diameter, with 30" of concrete below the fill line, so I don't have any choice but to use concrete.
> 
> A neighbor just had a 20 some year old barn torn down due to rotted posts which had also been in concrete and that got me to wondering what else I could do to help avoid a problem down the road.




I seal the end of every post I put in the ground.  Keeps water from wicking up the wood.


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## tv_racin_fan (Jul 1, 2008)

IF you are dead set on setting the posts in concrete you need to set them on gravel at least six inches thick and running up the sides of the posts about two inches. This allows any moisture that gets into the posts to have a place to run out. Honestly setting them in concrete is just asking for trouble in my opinion, they will eventually rot no matter what you do.

That said the absolute best thing is to make a footer from concrete with a post anchor on top of it to set the posts into.  Such as this one.   http://www.fastenal.com/web/products/detail.ex?sku=0123581


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## jimbo4116 (Jul 1, 2008)

tv_racin_fan said:


> IF you are dead set on setting the posts in concrete you need to set them on gravel at least six inches thick and running up the sides of the posts about two inches. This allows any moisture that gets into the posts to have a place to run out. Honestly setting them in concrete is just asking for trouble in my opinion, they will eventually rot no matter what you do.
> 
> That said the absolute best thing is to make a footer from concrete with a post anchor on top of it to set the posts into.  Such as this one.   http://www.fastenal.com/web/products/detail.ex?sku=0123581



That type anchor will work if the barn will have siding or crossbucking to give it lateral strength.  Will not if it is an open barn.  The barn will fold like an accordian, seen it happen.

The secret is using PT treated for the use intended.

In either case if you do use a fastener, bolts, lag bolts or nails in PT lumber be sure they are all hot dipped galvanized.


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## mattellis2 (Jul 1, 2008)

ranger1977 said:


> Dan, do the hurricane resistant codes mandate that the post be encased in concrete?  The reason I ask is because simpson strong tie makes several anchors for post to concrete connection where you install the anchor while the concrete is being poured in.  The top of the anchor is exposed and after the concrete cures, you can connect the post to the anchor. These connections have several thousand lbs. of uplift resistance. The post is insulated from the ground and the concrete so you really never have to worry about moisture.  Just wondering.



thousands of pounds of uplift resistance doesn't really help when he only has 300 lbs of concrete to resist the uplift force.  he'll pick up a little bit from skin friction with the ground, but it won't be much.  further, the embedded pole/pile makes for a more stable structure.  the simpson anchors act like a pinned joint at the top of the concrete...the poles can rotate more easily when only attached at the top of the concrete.

to the OP.  we coat all structural steel below grade with a bitumastic compound for corrosion protection.  it is essentially a roofing tar, so i would suspect you would be doing yourself a favor coating your 6x6's prior to placing them.

-matt

-matt


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## mattellis2 (Jul 1, 2008)

jimbo4116 said:


> That type anchor will work if the barn will have siding or crossbucking to give it lateral strength.  Will not if it is an open barn.  The barn will fold like an accordian, seen it happen.
> 
> The secret is using PT treated for the use intended.
> 
> In either case if you do use a fastener, bolts, lag bolts or nails in PT lumber be sure they are all hot dipped galvanized.



jimbo is correct.  again...it has to do with the pinned vs. fixed connection at the top of the concrete.

-matt


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## jimbo4116 (Jul 1, 2008)

mattellis2 said:


> thousands of pounds of uplift resistance doesn't really help when he only has 300 lbs of concrete to resist the uplift force.  he'll pick up a little bit from skin friction with the ground, but it won't be much.  further, the embedded pole/pile makes for a more stable structure.  the simpson anchors act like a pinned joint at the top of the concrete...the poles can rotate more easily when only attached at the top of the concrete.
> 
> to the OP.  we coat all structural steel below grade with a bitumastic compound for corrosion protection.  it is essentially a roofing tar, so i would suspect you would be doing yourself a favor coating your 6x6's prior to placing them.
> 
> ...



Not to beat this one over the head, but coating the vertical walls of the PT 6x6s will do no more than the concrete does. Sealing or waterproofing the bottom end will in effect create a water container of the post.  Metal does not wick moisture from above grade, so coating everthing below grade makes sense. The object is to leave the bottom of the PT post as is, so any wicked moisture will exit via gravity.

If the posts will be below the ground water level, that is another can of worms.


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## Dan Rogers (Jul 5, 2008)

*thanks for all the input...*

I guess I'll let the PT posts do their thing.  I'll put a stepping stone at the very bottom of the hole to help prevent pole sinkage with some drainage rock on top.  The remainder of the pole will be natural except for the 30" below the fill line that will be in concrete as per the engineered plans.

If anyone is looking for a pole barn, check out www.panhandlesalvage.com.  That is where I got it.  There are three of them on the property where I camp and they're very good for the price.  The metal trusses, which can be bought separately if it doesn't have to be engineered, make things a lot easier.


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## jimbo4116 (Jul 6, 2008)

Dan Rogers said:


> I guess I'll let the PT posts do their thing.  I'll put a stepping stone at the very bottom of the hole to help prevent pole sinkage with some drainage rock on top.  The remainder of the pole will be natural except for the 30" below the fill line that will be in concrete as per the engineered plans.
> 
> If anyone is looking for a pole barn, check out www.panhandlesalvage.com.  That is where I got it.  There are three of them on the property where I camp and they're very good for the price.  The metal trusses, which can be bought separately if it doesn't have to be engineered, make things a lot easier.



I'll give you another tip. assuming you haven't done this before. 

Make sure your poles are square at the bottom by cross measuring your layout lines.  But also make sure the poles are square at the top before you put metal or sheathing on the trusses. 

The poles will twist while the concrete sets.  Run a small cable and turnbuckle from each opposite corner post.  Cross measure at the top of the corner poles and use the turnbuckles to pull the top square.

This will make putting the sheet metal roof or plywood sheathing go one alot easier.

another tip when doing your layout with twine,  tie the ends of  the lines to concrete blocks instead of stakes.
The blocks are easier to move around rather than tieing and untieing to batterboards or stakes.


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## LYNN (Jul 7, 2008)

If your plan calls for buried posts, that is most like ly what the inspector will require. You might call the inspector and ask if tar is a good idea and mention the simpson ties. If he says that is acceptable then you can use L bolts and the Simpsons. It just neens a real good tie to the ground. Your manufacturer might also have an alternate method that he can send you an ammendment on. 
 I put posts in the ground with tar in Mexico 20 years ago but don't know how they are doing now. But that is the best way we knew at the time.
But there are also steel posts with bottom flanges that will work and do work everyday on steel buildings. 
Good Luck


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