I'm installing some 4×4 Pressure Treated 8' Tall Fence Posts for a chicken run. I want to have at least 7' tall fence, and am wondering if the 1' sunken depth is adequate. I have read conflicting information as to what I should do and the methods to use. I am also not building a wooden fence, just a light poultry wire mesh.
My plan was:
I so far have dug 7" Diameter x 18" Deep. Wanted to put 3" of Concrete, 3" of Gravel, to be left with 1 foot of sunken post depth in the soil. Then Soil+Gravel Mix all the way to the top, tamping as I go to compact.
I plan to be using 1" poultry chicken wire mesh for the perimeter, with a gate on one end between 2 posts.
My 3 questions are:
- Is 12" Sunken Depth good enough for a 7' tall fence? How deep do I need to go for such a light application of netting/wire mesh?
- Do you think the 3" of gravel atop the 3" of concrete will be sufficient to prevent moisture wicking into/against the post to increase its' life?
- Do you think that 6' will be sufficient to keep predators and deer away from the poultry if I have to dig the post deeper?
I definitely don't want to install these more than once, and if I have to dig deeper I will.
Best Answer
If you already bought (and can't return) 8 foot wooden posts and you want a 7 foot high fence (or "at least 7 feet") I would suggest not burying them at all, as that's doomed to failure. Put metal post bases (or metal posts) in the ground and bolt your wooden posts to them. Otherwise buy 10 or 12 foot wooden posts if you want 7-8 feet above ground and you want them to stay put. Or, bury them 3-4 feet deep and bolt 2x2 or 2x4 lumber to them aboveground to get to 7 feet (or more) above ground level.
If you didn't already buy them I suggest you learn about metal posts, they are usually much less expensive and easier to set, as well as somewhat safer around livestock than PT wood. But you still need enough post in the ground to hold the post in the air stable, and unless you are drilling holes in solid rock to place your posts in, a 1-7 ratio is dubious in the extreme - and so is placing concrete footings above frost line. In reasonably solid ground an 8 foot post can be driven in 2 feet and leave 6 feet above ground, but your corner posts will definitely need some bracing to stay put, and/or will need to be longer.
Wire (mesh or not) is actually more demanding on the posts than a wooden fence - the wire pulls and provides no support - wooden fence sections provide some bracing to the posts.