[Jim Ignatowski]

I'm planning on putting a post and rail fence around a portion of my property perimeter. In the past I've put them in and set the posts without any concrete and they usually last around 10 years (locust post and rail). This time around I'm considering using concrete, but setting all the posts in concrete would be a massive effort. I recently read some advice suggesting using dry concrete to set the posts ... Any thoughts on this? It would certainly save a lot of time and energy. Thanks

 

[Msradell]

Since you are installing a post and rail fence wind loading will not be a major issue. You should be perfectly fine without using concrete. Just be sure to tamp the soil around each post firmly to make sure they are stable. As you stated using concrete would be a lot more work and probably unnecessary in your case.

 

[wrongdave]

I set my fence posts with crushed stone (like the stuff you'ld use for a compacted base under pavers). I have no idea if it shortens their life compared to concrete, but I know it makes for a firmly set post and I can easily dig it out later if I need to replace the post.

 

[cibula11]

Where do you live? I'm not sure why it would be that much more involved. Once the holes are dug you could set the posts, and pour in a dry mix of concrete and let the moisture from the soil take care of the rest. I guess it depends on the longevity you wish to have with the fence.

 

[oberkc]

I put a privacy fence in about 20 years ago. I used dry concrete mix and thought that it worked beautifully. I have since moved, but they appear to still be standing.

 

[Jim Ignatowski]

Thanks for the replies everyone. I put in a locust post and rail fence at my last house and the posts were still standing after 13 years without any concrete, just proper tamping. I replaced a bunch of rails though. Anyway, I was considering using dry concrete this time around to decrease the likelihood of the posts rotting prematurely.

 

[oh'mike]

. Anyway, I was considering using dry concrete this time around to decrease the likelihood of the posts rotting prematurely.

No---concreting in the posts will shorten the life ----

water can dissipate into the soil faster when gravel is used---concrete can cause the water to sit around the post like a board in a coffee cup.

If concrete is used---pour a few inches of gravel around the post before adding your concrete--so there is no bottom in that coffee cup.

 

[Jim Ignatowski]

Thanks, I've heard that before about using concrete. I'm beginning to lean toward using a creosote wood preservative on the portion of the post that is in the ground and putting pebbles on the bottom for drainage. If I can get 15 years out of the post, that's fine with me. My plan is to plan some hedging on both sides of the fence anyway.

 

[Daniel Holzman]

This topic has been debated on this forum for at least three years. Some, like OhMike, take the position that concrete attracts or traps moisture, and shortens the life of the post. Others have said that there is absolutely no evidence for this belief.

I have put in posts using three different methods, for what it is worth here is how the techniques performed.

I put in six 4x4 cedar posts in concrete 20 years ago for a fence. To date, the posts seem to be in perfect condition. I put in a 4x4 pressure treated mailbox post in gravel/soil mix 20 years ago, to date no issues.

The previous owner of my house installed two long cedar post fences in 1959 using direct burial in soil. After 50 years, all of the posts are rotten.

I built a deck using 6x6 PT posts installed on concrete sonotubes using Simpson standoff brackets. Only been two years, but so far no damage. I have seen similar deck designs where the posts have lasted at least 20 years.

I like the idea of using dry concrete mix, let the moisture in the soil wet the concrete. It might take a year to fully cure, but so what, you don't really need any strength. From my perspective, it seems that the concrete would harden right up against the post, leaving little or no room for moisture to penetrate against the wood. Even if a little moisture wicks through, I don't really see this as much of an issue. I would like to see a definitive study on whether embedding posts in concrete is really a problem, I have not found one yet.

 

[mattiepearson]

I have personally always used concrete in one form or other, placing medium stones around the base first and forcing the concrete through gives a rock solid base (pardon the pun). In terms of rot, I have always treated the buried section and about a foot above the ground. Remember that the buried section should be a third of the visible height.

 

[vsheetz]

Yup, differing opinions abound. I am in the dry concrete camp. Dig hole, toss in some stones or what-have-you in the bottom, place the post, pour in a bag of quick setting dry concrete, add water and mix, mound it up so water does nit pool around the post, plumb the post, and move on to the next post...

 

[Dave Sal]

If I were going to put in fence posts, I would set them in concrete. BUT, in order to have them last more than 10 years or so, I would first attach a metal post support rail and then set them both in concrete as one unit. If the wood rots after a few years, the fence posts will still be supported by the metal rail. I had a 6' cedar fence installed in the early 80's and after a few years a few sections blew down due to high winds causing the posts to snap at the ground. Turned out they were partially rotted already. The fence contractor came out and redid the posts but I wanted something that would last longer and they supplied metal supports. (pic attached) To this day, about 25 years later, those posts are still standing. Unfortunately, the fence contractor no longer has those support rails and when I called a few years ago they didn't know where to get them. Here's a link to another company that has a different version of support rails. By the way, the support rail in the attached pic is on the neighbors side of the fence so I don't even see it.

http://contractors.masterhalco.com/Contract.nsf/woodpostmaster?OpenForm