Quote:
Originally Posted by 4X4
It'll take more than one random post on a messageboard to convince me that using large rocks to fill post holes builds a fence sturdier than using concrete in the post holes.
Treated 4x4s 3 or 4' deep with concrete should last longer than most people live in a house. How many fences have you lived through, FH?
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I've built several fences, and I actually agree that a post in concrete will cause it to degrade faster. It's not complicated, water gets trapped in between the post and the concrete and stays there, the freeze/thaw cycle serves to drive the water and minerals into the post and also tends to prevent it from drying out.
Having said that, putting a good bed of gravel before you poor the concrete helps. It is also a really smart idea to use 4x6 posts instead of 4x4 they last much longer and resist warping far better. I built a fence about 4 years ago and did use concrete because there is a slop on one side of the fence, and the soil there tends to move and erode to an extent so I was not confident the posts would stay put if I only used gravel and soil. But if you are running a fence on mostly level ground, then IMO it is better not to use concrete, but if you do this, you must absolutely pack the ground properly under the post, and pack the ground around the post aggressively, and go at least 3 feet down. If you don't, the posts will probably drift and become crooked over the years.
I can't stress enough, use 4x6 posts the extra cost is well worth it.