Lumber Yard® said:
[blockquote]Mr_Mike said:
[blockquote]slambubba said:
[blockquote]Martin S. said:
I don't understand how you can bury your posts in the dirt. Don't they eventually rot out?
I had the same thinking of you when I was researching my pole barn. Concrete will causes the posts to rot faster than dirt. My 6x6's are actually 3 laminated 2x6's which allows better chemical penetration and better lumber to be used. Mine building has 50 year warranty on treated lumber so I'm sure they know what they're doing.....
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Why is this method of construction OK for a barn, but not a house? I understand the strength you get from having a continuous cantilevered beam... (or almost none).
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My 6x6 posts are also laminated 2x6. My posts are 100% above ground as I used Simpson concrete/column anchors to secure the posts to the concrete columns. My sidewalls/ posts aren't 16' like Mike's, I only have 8' sidewalls.....I spoke with several contractors and the guys who knew what they were talking about recommended using the column anchors.
With that being said, my father has built numerous pole barn/shops in the very wet Pacific NW. He direct buried all his treated posts into the concrete columns and never had any issues.
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You fellas need to check out the blog on Hansen Pole Buildings website. Not saying the guy is right on everything but he discusses this kind of stuff ad nauseum. I have been heavily researching these things for several years now and I have personally built one pole barn myself, and have built severally professionally on a framing crew, and helped family members build several more.
I know a heck of a lot more about the theory of construction of pole buildings now than I ever did when I was actually building them. My take on the concerns above is this:
1. Any post will eventually rot out. Telephone poles are replaces almost purely for this reason. They, like pole barn posts, rot out at the ground line. I don't know the specifics why but that is where they rot the most to the point where they eventually lose structural integrity. There are precautions you can take like making sure the post is treated to .8 CCA. It should be marked on the posts you buy. Regular treated posts at the BORG will not be treated to .8 more like .5 so don't use them. Use only posts that are specifically treated for burying in the ground. Most pole barn builders and pole barn kit suppliers know this so you will usually get them if you go that route. Does not hurt to check though.
If you can get it past the building inspector I would use the 2.5 CCA stuff they use for saltwater docks and bulkheads. It has been banned from most residential use though plus if you live inland from the coast, you wont be able to find it. There are also wrappings and coatings you can put on the post where it will come into contact with the ground. Anecdotal evidence has shown this to be effective in preventing post rot.
2. The laminated posts vs. solid wood posts has been beaten to death and back to life again. Both sides swear by their opinion and condemn the other. My take is that once again, anecdotal evidence has proven both are effective. IF a solid post is properly treated I think it will last as long as any laminate post that has had its boards individually treated. With SYP posts they threat them until they wont take anymore chemical. That sounds like it is treated pretty deeply to me. Once again, the posts at the BORG are not treated this way. Make sure you know what lumber you are buying.
3. The posts being above ground raises some interesting questions too. Some say, and I tend to agree in theory at least, that putting posts on the concrete with Simpson ties or the similar Perma-Column/Sturdi-Wall products will negate one of pole framing biggest advantages. That being the physical nature of a post being buried in the ground (surrounded by concrete or gravel) will give the structure tremendous shear resistance to wind as well as uplift and whatever else puts stress on the structure. Differing construction methods can negate some of this such as plywood/OSB sheathing on the outside walls.
Once again though, anecdotal evidence has shown that this is of no great concern. Im pretty sure a tornado is the only thing that could move a pole building built with the posts set on top of the concrete. I have built one pole building this way and even though it seemed like it should not be stable, it surely was.
4. There are plenty of houses built like this throughout the country. I have only been a part of building one. Sometimes local code forbids pole framing for a residential dwelling though. It is still a durable method of construction if the proper precautions are taken with the posts.
