Depth of Pole Barn Posts?

[MarkV]

Well the right answer is whatever your local building department wants. Give them a call, they will tell you. Here is like others have said, 4' deep x 16" hole with a 6" concrete bottom. Backfilling with concrete, gravel, stone dust or native soil is a much debated issue. Some swear by concrete and others feel it traps moister nest to the wood.

As a side note, in your other tread you mentioned building a living space on the second floor of the barn. That is the one thing I would not be too vocal about with the code people. All depends on your local regulations but in many areas they don't allow that unless the whole building is brought up to same level of code that a house would be.

MarkV

 

[Mike120]

It depends on where you are and your ground conditions. To get the right answer you need to do a soil boring. Here, I've got sandy loam (and a high water table) with a clay layer at around four feet. The sandy loam is great for crops but won't support anything. I had to go down five feet to get to anything solid. I also had to build a 36" pad (24" under the barn) to put under the slab so it would be supported. Because I'm in the gulf coast area I also had to design for high wind loads.

Even though I'm a Civil Engineer, I still had to get a third party to do the soil boring and stamp the foundation design for my house to get a structural waranty. The boring was close enough for me to use for the barn and other buildings and I've had no problems with getting building permits and everything insured under my farm policy. Being a typical engineer, I probably over-engineered everything, but I have a lot invested and don't want any questions if I ever have to make a claim. As I recall, the soil boring was less than $150, but now I know exactly what I'm dealing with and can plan appropriately.

 

[catfishdaddyengineering]

Great looking barn! I have plans that call for the same under roof (16ft) and they call for 20ft poles with 4ft in the ground. My plans when built will look just like yours, just a little bigger: 44W (20ft center plus 12ft sheds) x 40L.

 

[Stimw]

I when 4' to give the hurricanes something to tug on!
I coat everything in the ground with used motor oil, even PT wood. I put it on with a paint brush and allow to soak in and if it soaks in too much I retreat before planting.