fence
My neighbor has requested that we remove our current shared old/broken 6' cinder block wall and put up an 8' high horizontal slat wooden fence.
The distance between the posts will be ~5.5'.
My question is how deep do I need to put the fence posts? This will help me determine the length of the fence post.
Don't attach the fence to the house. Aside from putting holes in your siding (not a good thing), your fence and your house will most likely move differentially. The attachment could result in a tear of the siding, which would be a bad thing.
Place the fence post close to the house, then run the fencing top and bottom supports up to within an inch or so of the siding (do leave a little gap, for that differential movement). Place the slats on the supports, allowing the slats to get just a bit closer to the siding.
You could even install a flexible membrane, similar to a product used to seal the bottom of a garage door at the floor, between the fencing and siding.
The main con is that since its designed to be driven down, the tapered tip will offer less torque, even set in concrete, than a post set to a similar depth.
Another consideration is frost heaving. The bare adapter should not heave, but the combined concrete/adapter might, unless the pour goes below the frost line. This can be mitigated with SONOtubes use.
I wonder if using 2 ez-mender, set in concrete, might not give a more stable base.
(from the website: "Post bases do not provide adequate resistance to prevent rotation about the base and therefore are not recommended for non-top-supported installations such as fences or unbraced carports")
Best Answer
Are you setting the posts in the ground, or in concrete? How deep is the frost line in your area? Have you contacted your local building department? There may be local codes and ordinances that stipulate the depth.
A common rule of thumb, is to dig the hole 3 times as large as the post, and to a depth of 1/3-1/2 of the post height above ground. so for a 8' high fence, using 4x4 posts. dig the holes 12" in diameter, to a depth of 2 1/2 - 4'. Of course, that's assuming you're setting the posts in concrete.
If you're going to put gravel at the bottom of the hole, you'll have to dig the hole that much deeper. Gravel is optional, and dependent on the drainage characteristics of the local soil.