Pole barn post question

[jimpad]

I'll soon be building what we locally call a pole barn.  The practice around here is to sink pressure treated posts into the ground four feet.  I do not want wood to dirt contact in any way so I plan to bore holes, fill with concrete, and connect the pole to the concrete somehow.  Is there a generally accepted method of attaching poles to concrete which will provide the same force resistance as planting the pole in the ground?  Budget is extremely tight and does not allow for purchase of the factory made brackets or the precast pilings.

[Drivadesl]

I never built a pole barn, but, I'm planning a similar method for my saw shed which expect to complete this summer. Like you I'm pouring a concrete pier that extends above ground level, and attaching the post with ties embedded into the concrete.   I imagine you could fabricate your own brackets if not wanting to buy, though I have not priced the factory ones.

[Crusarius]

I don't know if code still alows it but a simple anchor bolt poured into the concrete is the quickest and easiest option. then end drill the post and set it on top of anchor.

This may not be up to code depending on your wind zone.

[Jim_Rogers]

Concrete 8" above finish grade would be nice. Put some metal straps into concrete and secure them to the sides of the posts.

Or use the "short pole" system.

With that you bore your hole, put a piece of PT pole in the ground, back fill with crushed stone so water will drain, and then put a regular pole on top. Sister PT on sides.

10-20 years from now when post in ground rots out (if ever) then just replace the bottom piece by holding up barn and taking out rotten piece.



 

Jim Rogers
Wood is cheaper then concrete.

[jimpad]

I never built a pole barn, but, I'm planning a similar method for my saw shed which expect to complete this summer. Like you I'm pouring a concrete pier that extends above ground level, and attaching the post with ties embedded into the concrete.   I imagine you could fabricate your own brackets if not wanting to buy, though I have not priced the factory ones.

How do you plan on forming above grade... sonotube?

10-20 years from now when post in ground rots out (if ever) then just replace the bottom piece by holding up barn and taking out rotten piece.

It's actually going to be a house so I don't want it moving around if i can help it to; minimize drywall cracking, etc.

I don't know if code still alows it but a simple anchor bolt poured into the concrete is the quickest and easiest option. then end drill the post and set it on top of anchor.

How do you then secure the anchor nut... or is the post just set on top of the bolt without fastening it to the pier?  No codes where I'm building.

How do you do multiple formatted quotes within a reply, I could only see how to do the one?

Thanks

[flyingparks]

These are about $5

 

[ChugiakTinkerer]

Might be on the too-expensive side of things, but the Timberlinx A475 is used to anchor a timber post to concrete.

http://www.timberlinx.com/cat_a475.html

There's a guy on Craigslist in Anchorage with 16 of these that he's been trying to sell for several months.  Might be worth making contact if interested, but caveat emptor and all that.

Finally, here's a project that used these anchors: http://www.frankladner.com/shedproject/

[bucksnort]

Cut the bottoms off 5 gallon plastic buckets, ( cheap sonotubes ) Half inch plate stock sunk in concrete leave enough above forms to bolt into posts. worn out snow plow blades would work or scrap yard.

[Crusarius]

How do you then secure the anchor nut... or is the post just set on top of the bolt without fastening it to the pier?  No codes where I'm building.

How do you do multiple formatted quotes within a reply, I could only see how to do the one?

Thanks

Yes. just set the pole on the rod. That is the reason I mentioned wind loads. A good wind may lift the corner of the building.

I think the $5 plate will be the best option. I didn't even know those existed. To bad I am using rough cut lumber otherwise those would be great.

[ChugiakTinkerer]

...
How do you do multiple formatted quotes within a reply, I could only see how to do the one?

One way is to open separate tabs for each message.  I right-click on the Quote link and select Open in New Tab option.  Select and copy the text you want to quote, then paste it in another tab that has the message you want to send.  It's a little cumbersome but gets the job done.

[jimpad]

I like the 5 gallon bucket idea with the 5$ bracket.  How do you hold the bucket in place... I wouldn't want to set it on the ground so I'd have to bore the hole bigger than the bucket diameter so the bucket would be hanging in space.  I can think of a number of ways to support it but any ideas on the best way to hold it in place and level it?

[ChugiakTinkerer]

The last time I poured in sonotubes I just screwed the tube to a pair of 2x4 that extended over the hole.  That works when the bulk of the sonotube is hanging below the screw points.  For a bucketube you'll probably have a top-heavy arrangement.  Perhaps a 2x4 with a plywood triangle attached to raise the attachment point higher?  Heck, just a 2x4 tee on each side of the bucket ought to work.

[bucksnort]

I like the 5 gallon bucket idea with the 5$ bracket.  How do you hold the bucket in place... I wouldn't want to set it on the ground so I'd have to bore the hole bigger than the bucket diameter so the bucket would be hanging in space.  I can think of a number of ways to support it but any ideas on the best way to hold it in place and level it?

dig the top of your hole down a few inches (4-6) the same diameter of the bucket top and set the bucket in the recessed hole lower or raise the bucket in the recessed hole  according to the grade you want. Throw some dirt around the sides of the bucket to stabilize . My uncle use to do this with ice cream containers. I would throw some rebar down in the hole before I poured all the way to the top.

[MrMoo]

I built a pole barn 10 years ago. I brought the sonotubes out of the ground about 8 inches. The carpenter just built the walls consisting of poles and perlins on the ground and tipped up the walls putting the butt of the poles (three 2x6s) on top of the concrete without any fastners. It met code and has not moved since.

[Don P]

It may have passed inspection, it did not meet code. Gotta hold the building down, prevent it from sliding or tipping and brace it. That is also the problem with dropping a post over a pin.
Here's another way, I cast some scrap with hooks of rebar in the footing, made hinges out of pipe attached to sections of reinforced I beam scrap which allowed tipping it up then welded the plates together. 1/2" lags run up 8" into the post bottom. The footing is a 2x2 square hole (a 4 square foot footprint, think about soil load) it extends 2' down to frost depth and is a 2x6 above grade, just a simple box form that spans the hole.


I use knife plates on porch posts pretty often, that would be another way


When a post frame building doesn't pick up lateral resistance from having the posts embedded in the ground it needs to get that bracing from somewhere else.

[LeeB]

Mine is just for a barn. Cedar posts straight in the ground. It will last 20 years. I may or may not last that long.  :D



  

  


 

[flyingparks]

It may have passed inspection, it did not meet code. Gotta hold the building down, prevent it from sliding or tipping and brace it. That is also the problem with dropping a post over a pin.
Here's another way, I cast some scrap with hooks of rebar in the footing, made hinges out of pipe attached to sections of reinforced I beam scrap which allowed tipping it up then welded the plates together. 1/2" lags run up 8" into the post bottom. The footing is a 2x2 square hole (a 4 square foot footprint, think about soil load) it extends 2' down to frost depth and is a 2x6 above grade, just a simple box form that spans the hole.

8) 8) 8)

[jimpad]

Yeah, I'm keen on having it well anchored.  We had a storm here a few weeks ago and my 80 year old tobacco barn which just sits on some blocks did fine; many pole barns got destroyed.  The tobacco barn has a lot of 16' diagonal braces whereas the pole barns around here have very little... especially at the door ends.  I think once the building starts racking the holes wallow and the posts pop out of the ground.  That racking force has to be resisted somehow hence my concern with the joint.  After thinking about it I don't think the $5 bracket is right for me.  The short post solution is probably the strongest but I really have a hard time putting wood in the ground. 

These are nice https://permacolumn.com/what-are-perma-columns

I thought I saw a post on here somewhere using a plastic pocket below ground level... anyone familiar with them?

[Don P]

I have a hard time buying that the earth is a permanent brace for the reasons you mention, mud wallows. Those big diagonals are the key, triangles are rigid. Add more sides without triangular bracing and you get a wrecktangle. The $5 bracket, the knifeplate, my hinge, the permacolumn, all of those have very little moment resistance to that tall lever arm above them. Your rack bracing fore and aft and side to side are the key.

[jimpad]

Slowly convincing myself to go with convention 2x4 stud construction.

[reedco]

          Some where I have seen strap bracing put on diagonally before the sheeting, wish I knew about it before I built my shop!

[Don P]

You'll also see threaded rod and turnbuckles forming X's across the post bays on some. The steel sheathing can also accomplish this to a level, the industry uses diaphragm and frame interaction (dafi) in the design phase of those. All of that is when the pole barn "grew up" and became the post frame buildings we see today.

[btulloh]

Slowly convincing myself to go with convention 2x4 stud construction.

That may be the right way to go.  You said this was going to be a house, right?  With interior partitions, a floor system, real windows?  It's a bit harder to make a post-frame building into a house, IMHO.

[jimpad]

Yes, I did say it's going to be a house.  The whole story is, it's going to be a combo barn/shop/house until we can build our final house on this property, then it will be a barn/shop... hence the waffling on construction type. 

[btulloh]

Well it could go either way then.  Don't give up on the post-frame structure just yet.  It may be the best choice in the long run.  Only you can figure that out. 

Don't let all the discussion about bracing scare you off.  The bracing required is not difficult to implement.  It's not like the stud framing doesn't need bracing.  It usually gets it's bracing from the sheathing.  Before sheet goods were used for sheathing, they used let-in braces at the corners.  It's all about triangles, however it's done.

You may want to look at some plans to get some recommended practices.  Check this out maybe:  http://bioengr.ag.utk.edu/extension/extpubs/planlist97.htm#Roof Framing and Truss Plans

[woodworker9]

I have built several pole barns, and have also owned a concrete company for 26 years.  The reason why you sink pressure treated 4 feet below grade is to prevent wind from lifting your barn off it's footings.  A properly constructed metal fastener, like a Simpson strong tie, does not offer even close to the strength of wind sheer resistance as does a pole that is buried in the ground, with a "T" bottom to prevent pulling out.

My shop is a pole barn that has 6X6 laminated, pressured treated poles sunk 54" into the ground (frost line here in Northern Illinois).  After 17 years, there is ZERO degrade to the pressure treated posts.  Pressure treated posts that are surrounded by concrete will degrade within 20 years because the chemicals in concrete will eat away at the pressure treated wood, weakening it to the point of fracture.  I cannot tell you how many of these I have repaired/replace over the past 25 years, but it's over 1000.

Building a house that you plan on living in without properly securing it to a proper foundation to prevent wind sheer moving the building should be thought of as possibly being a rather risky endeavor.  I'm saying this in the nicest and least offensive way that I know how to type.....3 weeks ago we had 50 mph sustained wind gusts around the midwest.  There are pole barns everywhere that have been blown over from their mounts.  The several that I looked at for repair were all built and secured in a manner that would be consistent with the concept of unsavory engineering.

[jimpad]

No offense taken, you may have missed my coming around to understanding the necessity for a joint with the ground sufficient to withstand racking and by extension, uplift.  Can you provide more info on the posts you use... just standard lumber yard pressure treated or something special?

[Don P]

Woodworker9 sounds like he has much more experience than me but I can fill in a little bit on that until he can respond.

You can get foundation grade treated, the tag will read UC4B, most of what I see at the big box has a UC1 tag, green on the surface;
http://www.awpa.com/references/homeowner.asp

If you are not picking up lateral shear resistance from the soil, which is unreliable without having a geotech on board, then that resistance should come from the bracing of the building itself. Btulloh touched on this, it can come from the sheathing or from some form of diagonal bracing. Personally I believe in bracing a building as if the soil were not contributing, just as in residential construction. The sheets of plywood or osb do that in modern home construction, the steel in ag buildings provides that bracing and diaphragm. The posts in my pic above were not picking up shear from that connection and my sheathing is just vertical boards, so no diagonal bracing from that. I needed to provide some form of rack bracing to resist lateral loads from wind. This is not engineered, it is simply what I came up with to provide that bracing;

[woodworker9]

No offense taken, you may have missed my coming around to understanding the necessity for a joint with the ground sufficient to withstand racking and by extension, uplift.  Can you provide more info on the posts you use... just standard lumber yard pressure treated or something special?

Racking and uplift are two separate issues.  As stated above, racking is controlled by proper bracing of the building.  Each post is braced in both directions here.  Required by code.  I actually have the blue prints for my building here, but there's no way that I can attach them to this forum.  I am not complaining, but I have given up trying to post anything with the system used for posting such things here.  I can barely get a photo uploaded correctly.

Besides bracing each post, the building walls, once girts are added from post to post, are also braced on the diagonal from the bottom girt to the top girt, which helps immensely stiffen the building.   Even with all girts in place, a building will still sway a little until the bracing is put in.

As far as the post contact to ground, the posts we use are common to any pole barn construction.  They are 3 laminated pressure treated 2X6's for use under ground.  How they are built is with a 6', 8', and 10' length all clinch nailed together for ground contact.  Above grade, those joints are staggered, and regular construction grade 2X6's (non-pressure treated) are added to make up the rest of the length needed.  At the bottom of each post, which is set under ground to below the frost line (here it's 54") two 2X6's about 12" long are stainless-steel lag bolted to the bottom of the post.  This create's a upside down T, which prevents the posts from pulling out of the post holes once they are back filled.

Never surround a pressure treated post with concrete in direct contact.  Guaranteed way to get early failure.  The concrete eats the wood, even with the pressure treated chemicals.  We wrap the posts wherever they come into contact with wet concrete with a rubber membrane.....same stuff you use now to seal around newly installed windows before adding siding.  As stated, my shop is 17 years old, and there is ZERO degrade of the posts in the ground.  I poured an 8" thick concrete floor (I have 150,000 lbs. of machinery in there) re-inforced with welded rebar joints that is separated from the poles, and the bottom girts, with the rubber membrane around the entire perimeter of the shop.

When my company gets contracted for repair, I buy the posts pre-made from the local Menard's, which is a pretty big company for supplying pole barn components.  They are just the staggered pressure treated bottom section as described above.  We do the scarf joints and splice them in to the existing above grade pole already in place by just jacking that section of the building up 1/4" or so.  They come with all the proper nails which are shot in with a clinching gun, which is something that gives them extra strength.  It's the only way to pass code around here for a paying job, and code enforcement around the Chicagoland area counties is about as strict as it gets.  They all want a piece of the action, if you know what I mean.  I use Menard's because they give us a stamped engineering document and drawing for the posts which satisfies the county.  Without that, the liability would be on my company.   No thank you.

Hope this helps.  If not, ask away, and I'll give you what I can.  We're putting in 3 of these tomorrow morning.......

[sandsawmill14]

if you want to use the concrete you can just drill and anchor the post to the concrete with redhead anchors and a piece of 3" angle iron on each side of the post  here a stud wall on a concrete is anchored with redheads through the bottom wall plate every 3 feet    the redheads will bust the concrete when they pull out so there is no way to anchor it any stronger 

but they make at least 2 grades of pressure treated one of which is rated for direct ground contact and one just pressure treated for wet locations  if it were me i would just set the direct contact rated post in the ground and forget it   but here at home we just use cedar for the most part sometimes we will char the end before we bury it  and sometimes we dont

[jimpad]

Thanks for replies guys.  Don, that building looks beautiful.

[woodworker9]

Yes, Don, that work is exquisitely beautiful.  I meant to add this to my previous post last night, but I worked all day yesterday, and had one eye closed and one leg in the bed when I typed, and forgot to do so.

I love the X-bracing look.

[Don P]

Where's the smiley with the kid looking down twisting his foot in the dirt. Thanks for the kind words. That shop started with a timber on the tail end of the saw, "that looks like it'd make a nice start to a shop". It's sort of a box of chocolates build but it was fun.
I welded up a pipe windlass that we attached to some shelving that we X cable braced, then Michelle and I wound it up and tipped up the frames with it.

I've dropped the scraper blade "brake" in behind one of the orange windlass handles here when we took a break to check everything.


You can see Michelle walking around the right side in this pic during that pause. I built the frames on the cribbing in the foreground then jacked it up a bit to get a good pull angle to start. That's all the mess on the ground in front of it.

[Rural]

No matter how you 'plant it', with PT posts in the ground or Conc peirs and steel brackets diagional bracing is essential if you want it to last and stand up in a blow (actualy the same goes for a stud wall construction also). Pictured is my build where you can see the 2 x 6 diagonal bracing between poles. I also add diagonal bracing on lower stringers of the trusses and under the upper truss stringers to the peak, you can "get away' with a lot but miss the bracing and you are in trouble!