Replies

1. 
   Ruby | May 22, 2004 09:51pm | #1

   Don't know where you are but we set all posts on barns/sheds in concrete because of the uplift. We have fierce winds that would take posts supporting roofs and only packed in gravel right out of the ground, after a little wiggling around.

   Some of our posts have stood up to two small tornados that tore the roofs off. They have been in the ground without rotting many years, some 50+.

   We have more problem with insect damage, so we use treated posts.

2. 
   Piffin | May 23, 2004 02:07am | #2

   But Ruby is in the desert so rot is rare there anyway.

   I never set poles of any kind in crete. When I do repairs to it on jobs where it was done, here is where I see failures;

   - not only do the posts stay wetter because of the crete holding water and rot sooner, but when the wood absorbs that water trying to expand itself beyond the size of the pocket, the wod fibre is bruised so the post/pole is weaker.

   - When that water that is held to the post freezes, the crete is fractured and blows apart into two to three slices and a gap around the wood the next year so the post is loose.

   - When the crete is not poured into a smooth form, but in the hole only, the rough edges give tooth to the freezing soil to lift the whole thing out of the ground.

   The only time I would set poles in crete is to dig a deep hoile and pour the bottom 18" with a mix and then set the pole into it with spikes or rebar protruding so the pole has a ball anchor around it well underground to avoid frost, but a bit of a wider footing to support it.

   From what I have read and heard, this is a bit of a regional thing. most places where it is set in crete have little or no freezing and/or soils that allow the water to perc quickly through it - sandy or gravelly

    

    

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1. 
   TheOldCynic | May 24, 2004 06:42am | #3

   Seems "regional" is the operative word here.  Up here in Bluenose country, the Ag Engineers will tell you the quickest way to guarantee frost heave is to set the post in concrete to ground level.  Usual suggestion is to wrap the post with two layers of poly - 6mil is fine - from grade to below frost level,  the first wrap can be stapled to the post, but not the second, to allow it to slide, if necessary.  What actually happens is that the frozen soil slides up the pole without pulling it along too.

   Depending on the bearing capacity of the soil, sometimes a pad is poured at the foot of the hole (great way to level the holes), the pole placed and backfilled with what's available, which is mostly (expansive) clay, and tamped.

   Haven't seen any heave when done this way, or pull out even in Hurricane Juan, but did see a bunch of 6x6 that broke off about two feet above the ground.  The rest of that riding arena was scattered over about five acres.

   And PT is mandatory.

   Doc - The Old Cynic

   Edited 5/23/2004 11:43 pm ET by Doc - The Old Cynic

1. 
   Piffin | May 25, 2004 02:23am | #7

   Doc, A pad footing of some kind would definitely be needed when using that trick of double wrapping poly around it. That is fine for decks or fence posts, but part of the way the pole supports the structuire in a pole building is that ground friction holds the building up. It is not just the compressive strength of the soil under that 8" diameter - or whatever - pole that holds all the weight. 

    

   Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

3. 
   Blacky | May 24, 2004 02:44pm | #4

   Check out this address http://www.socketsystems.com its a neat idea for setting posts.

   The balance of the systems is different, has a bit of a learning curve.

   Blacky

1. 
   ANDYSZ2 | May 25, 2004 04:40am | #9

   I like the idea of tip up frames, and, how well built is the hardware and does  it seem strong enough after full assembly?

   ANDYSZ2I MAY DISAGREE WITH WHAT YOUR SAYING BUT I WILL DEFEND TO THE DEATH YOUR RIGHT TO SAY IT.

   Remodeler/Punchout

1. 
   Blacky | May 26, 2004 12:12am | #16

   Well you can get sealed drawings.  I really like the idea when I finally get around to building my own home I'm going to use a varition of the system.  The owner is a super fella and he will give you any support you need.  The best thing is that a pole building is not currently considered a permanent structure so its cheaper tax wise (pa)

   Blacky

1. 
   moonmlns | May 27, 2004 11:54pm | #18

   thanks to everyone so far. I hoped this would be interesting, and it has been. I have been building pole buildings in the Portland, Oregon; Vancouver, Washington; and Spokane, Washington areas for several years now. The area around Portland gets a great deal of rain and a lot of the ground is clay. Thus, the water stands in the holes. I know that pt takes a long time to rot and that fungus does not grow well on it, but I have always wondered about water pocketing in the post envolope. I know that water can easily wick up the post from the end grain, since that is what it is designed to do. I have considered filling the bottom couple of inches of the hole with gravel, setting the post and then pouring the concrete. But, this would only work in areas that drain well. I think the anckors at the web sight that blacky posted looked interesting.It alllows for the anchorage of concrete and holds the post off the surface. My only concern with the piviting anchors is securing the sway of the building. it seems to me that if you engeneer in steel strap X-brasing that could fix that problem. I'm looking forward to seeing your different perspectives on this. Thanks, again. This is really interesting and informative. This is my first time using one of these forum

1. 
   xMikeSmith | May 28, 2004 12:23am | #19

   pole buildings are designed to have their poles buried..

   if you don't bury the poles , then you have to come up with an alternative system of  permanent bracing .

   the horizontal framing in a pole structure does very little to sway-brace it.. the lateral resistance of the poles is integral to the whole concept..

   here in Rhode Island, the typical pole building is built with 4x6  PT SYP poles treated to .60 retention...

   our frost design is 40".. so you dig or auger 12" holes to or below that from FINISH grade.. we prep our sites by stripping the loam, bringing in a leveling pad of 18" of bankrun gravel.. dig/auger the holes thru the gravel,  pour a one bag footing and tamp level the top of the footing.. the top of footing is usually about 3' down.. it's flat so you can dance the pole into it's exact location using batter boards.. then we backfill with tamped gravel, locating and plubing the poles to their final location..

   frame the horizontals and trim the tops of the poles... after that it becomes pretty much convetional framing...or utility framing .. depending on the end-use..

   i've seen pole buildings built on above ground footings with bolted sills.. but they were framed with oak ... all of the PT ones are buried and i've never seen anyone who knows what tehy are doing encase the poles in concrete..

    but hey, whadda i no ?Mike Smith   Rhode Island : Design / Build / Repair / Restore

2. 
   MikeWalsh | May 28, 2004 01:46am | #20

   I don't build pole buildings.

   I've seen decks sink as the poles that were set into the ground sink in the soil, and decks are a bit lighter than buildings.  Usual practice here -- if you know what you're doing -- is to drop a prefab footing (or a big rock) into the hole before backfilling.

   I wouldn't think that gravel alone would do much for you.

   A good concrete footing, set down at the frostline, makes more sense to me.  I've used a post hole digger, at an angle, to widen the base of such a footing, but that's just me.  You can even run some rebar through the pole and drop it in wet concrete, to anchor it more, if you think a tornado can raise the building.

   As for water in the holes: if it's all clay soil, either pump out the water or use it to mix the concrete.  Although I don't recommend it, I know that some people just score the bag of concrete, and drop it in the water.  :-)

   I'd try to keep more water from running into the hole until the concrete sets.  Too much water weakens the concrete.

   And I like to dress the ends of any PT lumber with Cuprinol or some other penetrating sealer -- not Thompson's -- because I know that the wood will take it, and it might help some.  Pressure treating heartwood is of limited benefit, IMHO.  It seems to rot anyway. 

   Not that I'm an expert.  Just seen a lot of it.

2. 
   butch | May 26, 2004 01:21am | #17

   Thanks for that link

3. 
   DanH | May 28, 2004 03:31am | #22

   But that's not really a pole barn. A major reason for using buried poles is to provide some lateral resistance in the walls, allowing for less bracing than would othewise be required.

4. 
   gdavis62 | May 24, 2004 08:11pm | #5

   I used to live in the midwest where a lot of pole barns got built.  Soil conditions were mostly clay.  What I saw done, always, was for the pole footings to be poured in each hole, then posts set atop the cured concrete and backfilled.

5. 
   Isamemon | May 24, 2004 10:50pm | #6

   Where we are code makes us set them in concrete, we have no choice

1. 
   Piffin | May 25, 2004 02:25am | #8

   Where is that, and do you meqan IN or ON concrete? 

    

   Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

6. 
   bhackford | May 25, 2004 05:00am | #10

   I build a fair amount of pole barns. Historic ones and what I do is not historic at all. On 16in sono tubes I set a anchor bolt and then place a 2X8 flat on top with an addtional piece of 2X8 that is 12 in long on top of that to "bury the bolt". Then I wrap the outside with another 2X8 on edge so it stands up. I place the pole usually 6X6 hemlock on the double 2X8 and toe nail and also nail through the on edge 2x8. This works well because it keeps the hemlock off the ground and only the PT 2x8 touch. Let me know if you have additional questions. I am a better builder than writer!

1. 
   wivell | May 25, 2004 09:42pm | #14

   How about a sketch of the detail you describe?

7. 
   albeee | May 25, 2004 05:06am | #11

   Posts that are set in concrete and submerged in water will not suffer any degradation from any type of decay. The only time that wood is effected from decay is when the moisture content  (EMC)  is between 21% and the Fiber saturation Point (FSP) about 29%.  So if it is below 21% their is not enough moisture. If it is above their is not enough oxygen for it to grow. The correct answer is, it does not matter how you put it in the ground. Decay is usally going to happen between ground level and 18" anyway.

1. 
   Piffin | May 25, 2004 05:35am | #12

   My point is that when you surrond the post/pole with crete, it holds the moisture to the post so it remains at that higher moisture level longer and then rots faster. 

    

   Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

1. 
   albeee | May 25, 2004 08:57pm | #13

   Your explanation is great for explaining why a hammer handle gets loose expanding and crushing fibers then drying and getting loose, but wood science does not support your answer about the posts. A wood sample that has a moisture content of 100% is oven dried  to 0% will only shrink 8% along the tangential orientation. In use the moisture content of a post should range between 12% and 28% depending on where you live. That is really a small range. Not enough to cause the damage you described. 

1. 
   Piffin | May 28, 2004 01:49am | #21

   I'm not a theoretician wood scientist, just someone reporting on what he sees.. IO suppose it could be too that the water sodden post freezes and causes some breakdown too. 

    

   Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

1. 
   donpapenburg | May 28, 2004 04:44am | #23

   In central Illinois , Morton Buildings  pours a bag of sackrete into the pole hole . sets the pole  and backfills.  They don't use water because the pole would sink into the concrete. And the soil has enough moisture to cure the crete.

2. 
   Piffin | May 29, 2004 04:39pm | #24

   We do that here for porches or decks, but I would suspect the load handling of such a footer for a whole building.

   it is when the entire buried portion of post is set in crete that I see problems with advanced deterioration 

    

   Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

3. 
   donpapenburg | May 30, 2004 10:43pm | #25

   It must work in the midwest here as most of the building are still as tall as when built. 

8. 
   BossHog | May 25, 2004 10:01pm | #15

   Got enough opinions yet ???

   Here in central Illinois, I haven't seen problems with pole building posts rotting off, *IF* treated lumber was used. I've definitely seen non-treated posts rot off. Seems to take about 20 years or so.

   I prefer to see the posts in concrete. I think that's the best way to keep the building anchored and solid in high winds.

   In general, the art of government consists in taking as much money as possible from one party of the citizens to give to the other. -- Voltaire (1764)