is it necessary to set 4 by 4 inch fence posts in concrete, if they will be placed 3 feet deep?

Answer 1

No, it is not. In fact, some will argue (myself included) that it is unwise to put concrete next to a post. Treated or not. Concrete draws moisture from the ground and holds it next to the post, thus shorting the post life. If anything, I use stone in the first foot/ foot and a half of the bottom of the hole and then fill the rest w/dirt. This stone will shed water and pack as tight as concrete.

More important than what you use to back fill is how you do it. When back filing a post, put in 4" to 6" of dirt and "tamp" (pack) it in, using a pole. By tamping the back fill your securing the post tightly and will get less settlement after the first few rains.

3' may also be a bit of an over kill, depending on your area. You need only to go 2', or below the frost line for your area, which ever is deeper. Unless your building your fence in the northern part of the US, You may be doing a lot of unnecessary digging.

I fenced in a 130 acre farm w/several cross fences and built three pole structures. No concrete was used in any of these posts and there doing fine after 15 years.

Answer 2

I don't know if its necessary, but its pretty highly recommended. Its certainly a pain in the butt to do it though... the following is a good alternative if you don't want to deal with pouring concrete.

When we put up our horse fence, I believe we had 8 foot posts that were sunk 3 feet into the ground with 5 feet sticking out. Instead of going through the trouble of pouring concrete though we circular cement bricks and dropped them into the hole where the post was going to sit. (The circles were maybe 4" thick with maybe a 6" diameter or so). Then we poured dry concrete mix into the hole after sticking in the post. I can't remember the exact brand of mix as it was quite a few years back, but it was meant to be laid dry and had a gravelly consistency.

Anyway, we just filled the rest of the hole like normal, and we have never had any problems. We have tied some pretty green horses to them and they have never budged even after being wrenched on pretty hard. Well, I hope this helps! Good luck!

Answer 3

The answer will depend if the post is to hold the weight of a gate or a corner post that will hold the tension of two fences, or just a line post. If the 4 x 4 is just a line post then no you do not have to use concrete. But the other two will.

Answer 4

It depends...

If you have a "hard packed" clay soil, then no, it wont be necesary to do this, but, I would put the post on a 2" base of gravel for drainage and pack the post with the clay and gravel mixed.

If its sandy or loamy soil, then it would be a "must" to put the concrete in with the 4X4 posts, and make it so that the concrete has a "cap" on it (slight bevel sloping away from the post, so water will run off and not rot the post if it lays on the concrete).

I wish you well..

Jesse

Answer 5

I would put cement in them. I put up a small fence,( 8 posts) and put cement in them and glad i did. Its easy and not that expensive. Go to your local home center and get some quick setting concrete 1 bag per hole. Just put the post in the hole tack some braces to plumb the post on both sides then place the cement in the hole dry add water and walk away.

Good luck

Moskie257

Answer 6

I put my fence up two years ago, and I live in Florida, with all sand, and I didn't use any cement, and it worked just fine, now you can go out and try to shake my posts and you would think they were set in concrete

Answer 7

Well, the cement plug on the end gives you more surface area to bear the loads on the fence. But no, you don't "have to". Just don't be suprised if your fence is leaning after a year or 2.

Answer 8

I'm not sure but it's cheap insurance to just do it.

Answer 9

No it is not. They should support themselves at that depth.