Pole barn post question

[giffy]

I plan on using 4x6 posts for a pole barn and have a couple of questions. First I am seeing more pole barn structures going up using 2x6's put together to make up the 4x6......what are the advantages, disadvantages to doing it this way, and finally does anyone treat the bottom section of the posts (part going in the ground) with anything in addition to the normal PT posts?

As always.......thanks.
giffy

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GiffsFarm

[big rockpile]

All depends on how big this is going to be.On my barn I used 4X4 Oak,used Brackets set in concrete to hold them,so I didn't have the problem with them rotting.

Used 2X6 for Nailers and 2X8 for Rafters.29 ga. metal.

it all seems to be holding up just fine.

big rockpile

[agmantoo]

I have done what you are referencing however it takes 3 2x6 per posts to do make a good support. Here are the advantages that I am aware
You can have the in ground portion treated and not pay the expense of having the entire post treated. Typically the upper portion is in the dry and the treatment is not needed there. One person can easily handle the in ground portion and you can set the shorty section in concrete and have all your alignment in position without having to support the upper portion of the posts since you do not install the upper portion until after the inground portion is complete. When the upper post portion is inserted in the lower section you can do some minor error correction if needed. If you will carefully observe the orientation of the individual 2x6s you can build a post that is straighter and less likely to warp. Warpage is a major problem with conventional posts. Disadvantages are you must do more labor to create a post. The in ground portion needs to be nailed/bolted with noncoroding fasteners. Initial alignment is critical with the segmented posts if you elect to install them in two operations, with regular posts you can pour the concrete around the post after the structure has been "squared". Of course you could build the segmented posts completely then install them the same as a regular posts.

[rambler]

New wood is so knotty & warped these days. A 6x6 long enough for a pole shed (16-22') is mighty spendy with the whole thing treated, & mighty heavy, & gonna be warped, and a big knot goes all the way through, kinda weak.

The laminated 2x6's are stronger, are treated farther through, are cheaper (only need to treat the bottoms in addition to 2x being cheaper than 6x) and can be made longer if you want a real high roof.

The new thing is the Permacolumn, the Wick web site features it, a concrete bottom with a pole anchored to it. Won't rot, looks like a real good idea. Can make your own with sonotubes.....

--->Paul

[redbudlane]

We used old poles from our local rural electric co-op that they were replacing. We got some of them free and we paid a very low price for some others. The poles are still in excellent shape and are already treated. The disadvantage would be they are very heavy.

[Windy in Kansas]

I was doing research for a co-worker today. Wick and Morton no longer bury poles or posts for support. They both use a product called Perma-Columns.
http://www.permacolumn.com/

I also like the idea of used utility poles if one can get them reasonable. Around here one can't.

[tiogacounty]

A factory laminated post, for use in pole barn construction, has little in common with a couple of 2x6s nailed together. a laminated column is like a gul-lam beam. It uses specific grades of lumber, structural adhesives, finger-jointed butt joints and a lot of other special details to provide a post that is far higher quality, stronger and straighter than the treated, sawn stock they replace. You won't even get close to matching one by nailing one together on site. Also the idea of starting the poles on top of concrete pads with simpson/teco bases leads to a whole other set of issues that may be of concern depending on things like wind loads. A portion of the strength of a pole barn is the lateral resistance provided by the buried section of the post. A post that is 25% buried is a lot more resistant to side and upward loads than one that is nailed to a sheet metal base. Will this be an issue in many applications? Probably not. Will it withstand hurricane winds as well as a typical post frame? No.

[Highground]

If the post has to be buried, take a look at these.

http://www.postprotector.com/

[Boleyz]

Some of my support beams are laminated 2x6, but if you really want it to have lateral strength, put a strip of 1/2" plywood about 5 1/2" wide between the 2x6's.

Use a construction adhesive like liquid nail liberally on both sides of the plywood, and "sandwich" it between the 2x6's. then use your framing nailer and angle in lots of nails from both sides of the beam.

By adding the plywood you really raise the strength of your beam.

Edited to add:

If your post is going in the ground, get a can of black cold roofing tar and smear it liberally over the section of the post that will be in the ground. This simple step will add YEARS to your post.

[giffy]

Thanks all for the suggestions/replies, I appreciate it.

giffy

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GiffsFarm