built-up posts

[markb1]

Hello
I'm new to the board so a short intro:
Electrical contractor living in Oregon, enjoy vintage stereo, old cars, metal working garage saling, old stuff of all kinds and just hanging out at home.


I'm planning a pole barn 30' X48' and had seen somewhere that a post built up from 2X6 PT instead of 6X6 PT .

Seems that it would be easier to construct with the smaller lumber.

Has anyone used this method, or have a link to info on this type of construction?

Thanks Mark

 

[rodnok1]

The idea is the posts won't twist/warp when built from multiple layers, and with long posts it doesn't sound bad. I don't think it would be any easier overall, since you have to glue/screw all the boards together and 2x6's twist and warp to begin with, so getting treated wood to line up sounds like a challenge. I think you would need to change header attachment methods also, I wouldn't want to nail into 3 2x6's instead of 1 4x6. I also wonder about moisture between the wood layers in the ground, if it would quicken rot in any way.

 

[kbs2244]

I wowuld expect a cost factor also.
Foot for foot I think 3 PT 2x6's would cost more than 1 PT 6x6.

 

[Steve in Mi]

There were at least a couple of examples of the built up posts in threads I have viewed here but I can't say where now, I have trouble keeping so many builds straight. I did some searching on the web and saw a couple more examples but no info. I'm interested also in the idea of avoiding the triple gal nails and screws into the treated post above ground plus in one of the garage threads it was mentioned that the treament was more complete in the built-up post so it could conceively have a longer life.

I did find this on a possible alternative but didn't see any cost breakdown/pricing.
http://www.permacolumn.com/

There has got to be more information out there if I can come up with the right search terms.

 

[kbs2244]

I don’t know about the longer life argument.
The PT goes from the outside in, just like any moisture would.

 

[Vermaraj]

We use offset 2x lumber, usually called strongbacks, to build stronger walls than could be built with 4x4 posts. The 2x are lined up to look like an i-beam and then glued and spiked together. Since the fibers are lined up in different planes you eliminate the possibility of weak axis bending. The result is a member much stronger than solid wood.

In a similar vein if you used 2 2x4 and 1 2x6s to create a composite post it may be stronger, lighter and more resistant to warping than a 6x6 post. However, you need an engineer to determine if it will work for your application. When you add in the cost of labor to form the composite post and the engineering work there may not be any savings.

As an alternative there are all kinds of engineered lumber (like lvls) specifically built to be used as posts. They are straight and true and can be ordered pressure treated.

 

[markb1]

Thanks for all of input. Looks like 6X6 PT posts are going to be easiest, quickest method, but I'm not totaly convinced.

 

[RAYJAY]

I got a stockade buliding there built on a lam beam construction

http://www.stockadebuildingsinc.com/construction.htm

 

[markb1]

Thanks RAYJAY thats the link I was looking for.

 

[Steve in Mi]

Yes, yes, yes thank you RAYJAY just what I needed to know.

 

[ownsaglock]

A farmer I know had a pole building put up in the early -mid 80s with the built up posts. The company usually used soild posts but in an effort to cut costs switched to the built up. They eventually came back to encase them in concrete after complaints of early rot.

 

[Steve in Mi]

A farmer I know had a pole building put up in the early -mid 80s with the built up posts. The company usually used soild posts but in an effort to cut costs switched to the built up. They eventually came back to encase them in concrete after complaints of early rot.

There would need to be more data to evaluate that system with the technology of today. Preservative type, up-take level (% absorbed) and ground conditions (earth type). The built up post in the link is a 40 year deal (in writing) about twice the life span advertised in the 1980's example. I don't think the built up post will necessarily be a lower cost option but I could be wrong. I hope it is cheaper, that would be nice. It would work well for me as I have an abundance of untreated 2 X 6's on hand to attach to the treated **** ends. I would probably buy the **** ends not knowing what glue to use with the preservative. I see it as an easier build for myself too. Local code (if not everywhere) will not allow any fastening to treated post of today that isn't triple coated galvanize (read - not cheap) with the current preservative salts. I'm not committed to any particular method of construction at this point, only trying to line up the ducks.

 

[jwith68]

I have been investigating adding pole-construction lean-to's onto 3 sides of an existing barn. While searching for information, I found a ton of work done by Dr. David Bohnhoff from the U of Wisconsin Ag Engineering Dept. Anything related to pole construction, he has done something with, including a lot of work with laminated posts. Here's a link to his U of Wisconsin publication webpage. Lots of good material, just start digging.

http://bse.wisc.edu/bohnhoff/publications.htm

 

[kbs2244]

Since timber is a big deal in WI. the U of WI has a long history of real good stuff on wood construction.
If you are into wood construction, that link can lead to a real long session at the keyboard!

 

[ownsaglock]

Im under the impression that the old wood preservatives are better than todays. Is that incorrect?

 

[1320stang]

Morton Buildings does their posts like this. This way the whole post isn't pressure treated (doesn't have to be, Morton's go 4' above finished grade) and the pressure treating is easier to put into a 2x6 than a 6x6. At the top, Morton's trusses fit into the center slot where the 2x6 is missing in the top of the post which lends itself to a stronger connection as it becomes part of the post.

 

[Novadiecast]

You can order "factory made" built up posts from your local lumber yard. All the engineering is already done for you, and they are usually cheaper in quantity that regular 6x6's.

 

[markb1]

I like the idea of the trusses sitting in the center slot. Seems to be stronger and easier to set the truss.