Best to set fence posts in concrete or gravel?

[leadbelly]

Sure it has nothing to do with audio, but somebody here may just have unique insight....

I have tried to search the net a bit and find a bit more hard background info on pro's vs con's for using concrete vs gravel to set fence posts, but have come up short. I have seen many DIY guides describing one or both, but nothing with a good technical argument of one vs the other.

The big pro with concrete is that the sheer mass helps resist frost heaves, which is "the big deal" here in Canada. The big pro with gravel is that water drains away from the wood and prolongs its life, even for pressure treated lumber. But why do most commercial installers exclusively use concrete when it costs much more? Is the only reason because they save labour by dumping it dry in the hole and adding water afterwards?

So, any experience from you landscapers and/or woodworkers out there?

[speaker]

Originally posted by leadbelly
Sure it has nothing to do with audio, but somebody here may just have unique insight....

I am going with concrete for my fencing. The reason was long-term stability. New England has the same problem with frost heaves as you do. You should slope the top of the concrete footing away from the lumber. You'll minimize rot & deterioration that way.

speaker

[Da5id4Vz]

How bout setting a piece of 1 1/2" galvanized pipe into the concrete footing. Bore out the bottom of the post (4x4?) and set it down over the pipe.

I think there are brackets made for this, but they always looked as if they weaken the fence.

http://www.diydata.com/projects/wood...fenceposts.htm

[millwood]

my approach is slightly different:

1) dig a hole;
2) nail a pipe into the ground at the bottom of the hole. Leave about half a feet of the pipe above the bottom of the hole;
3) put in concrete;
4) before it solidifies, put in galvalized medal feet on the top of the concrete (you can get them from Home Depot);
5) you can then fasten lumber to the medal feet. so next time, if the lumber for whatever reasons needs to be replaced, you just unfasten it and you are done.

I have upgraded two decks like that myself. No problem whatsoever over 10+years span in the north east.

[Peter Daniel]

Medal feet is good for decks, when the post is affected by gravity forces ony. I'ts not recommeded for fences where the sideway pressure is much stronger.

I wouldn't be concerned at all with wood being affected by moisture when set in concrete. I don't think the post will see much water anyway. You can always protect it with a plastic wrap, before pouring concrete.

[kingdaddy]

If you use wood posts (I did) then put some gravel in the bottom of the hole so the post wont wick up the water, use the post to tamp down the gravel, then pour the concrete around the post.

I just finished setting 37 posts and nailed over 1000 pickets and I can say from experience, you got quite a job ahead of you.

[MikeW]

Will it be easier to take them out in fifteen years if you use gravel ?

[Da5id4Vz]

And then there are the products and techniques for treating posts before putting them in the ground:

http://www.postsaverusa.com/

[Ken L]

Originally posted by kingdaddy
If you use wood posts (I did) then put some gravel in the bottom of the hole so the post wont wick up the water, use the post to tamp down the gravel, then pour the concrete around the post.

Looks to me like Kingdaddy has nailed it down for you _grin_

As speaker said, be sure to slope the top of your footing so water will drain away from the footing and post. What you want is for the footing to drain to prolong the life of the post.

If you surround the upper portion of the post with sufficient concrete to resist the frost heaves you should be in good shape.

This method provides drainage, keeps costs down, is simple, easy, effective and makes good common sense.

Not often you get a solution that combines all of those elements _grin_

Many times, it seems to me that slightly more effort and say a 10% increase in costs/effort to do it right will extend the life of the fence, or roof, or paint, or floor resurfacing, etc by a good 50% or more - yet much of the time that extra effort is not made - I guess the contracters/installers have learned they lose bids on price - It is a philosophy I don't understand or adhere to.

Hope it works out for you.

Now if Kingdaddy will just come help you put those posts in, you'll be grinning.


Regards

Ken L

[johnkramer]

Originally posted by Peter Daniel
I wouldn't be concerned at all with wood being affected by moisture when set in concrete. I don't think the post will see much water anyway. You can always protect it with a plastic wrap, before pouring concrete.

I had to pull 60 some dry rotted fence posts out of the yard I grew up in. They were all dry rotted where the post entered the concrete. Had to dig out the concrete too. All when I was 12. And then there was the ants, thousands of them. Personally I would never use wood for the posts, but I like the idea of a wood fence. I'd be treating the wood with everything I can think of to fend off dry rot and ants/termites. Talk to a professional, it would be a major drag to have to pull up all that hard work.