concrete for fence posts

[QRTRHRS]

When I dump a dry bag of cement around a post, I like to poke around it with a piece of 1/4" rebar. Gets the air out and gets it settled into all the little voids much better than a standard tamping bar.

 

[Egon]

You should be able to do that.

 

[Mike120]

Thanks for he suggestions. I will use the normal stuff and add a little water. Mike I liked your suggestion to put the concrete in the hole and them pull the posts up to level but my posts have a square hole about 6-12" from the bottom. I am afraid the concrete will get in the hole and create a key not letting me raise the post. I am going to try to get them the correct hight to start with

Now for another question. I drilled some holes and some of them are just caving in. The soil is so sandy and rocky that is just doesn't hold together. Once I get the hole deep enough it will probably be 3-4 feet across. Could I just drop a sonotube, not sure of the spelling, in the hole then pack dirt around that and pour the concrete inside with the post?

I have no idea why they would put the hole there....I'd just cover the hole with a couple of layers of duct tape.

I've got a sandy loam but it holds together, I've never tried putting vinyl in shifting sand. A sonotube would be a possible, but $$, solution. Is it like that all the way to the bottom of the hole? Try calling Lee at Triple S, he seems to have a solution for most things related to vinyl and has shown me a few neat tricks that I've used successfully.

 

[czechsonofagun]

Tapped gravel is enough for a post, IMHO. I use concrete only for gates and corners. It is a horse fence I am talking about.

 

[tommu56]

want to set your posts about an inch deeper than where you want the tops. After you've got the concrete in the hole, lift them slightly to get some concrete under the post. This will keep them from sinking later on.

I would be concerned with lifting the post to let concrete in bottom up here in the north water will eventually get in there and freeze and brake post and concrete around it. Ive never set vinyl but for steel I put hockey puck (round concrete disk) under post 2~3" gravel then the concrete to just below grade.
This will provide footing (disk) drainage (gravel).

or fill post to the top with concrete after rails are in then it ain't going any were

tom

 

[Cat_Driver]

Speaking of letting bags sit out. I saw a retaining wall a guy built by just stacking cement bags. Over time those bags hardened solid, and when I saw the wall the bags still had paper on them yet they were solid. Strange but true.

I would think that perhaps you wouldn't have to every post to save some concrete. Depending on the soil do every other post or every 5-10 posts for stability.

 

[twarr1]

I've done it both ways on my high-tensile fences - put in dry cement and add water, and use mixed concrete. In my experience the mixed concrete worked much better. I would recommend it at least for the corners and braces. When you consider the time and expense you're putting into it, doesn't make sense to take questionable shortcuts.
About those "set-up" bags of cement- that cement is ruined, not properly cured.

 

[bota7800]

I put in flexible fencing from RAMM attached to pressure-treated posts. If you are talking about another product what I have to say may not apply. Really like the fence though - very safe and easy to maintain.

For the flex-fence, the instructions only call for concrete in the corner structure posts, the field posts go in dry. (If you have horses dry tamped is safer anyway) My fence was in Colorado - very dry ground - so I did not trust the dry mix technique - just my cautious approach. For the corners and gates I used a portable cement mixer driven by a generator. It was a pain moving both pieces of equipment but I would move it to a corner, cement in the 5 posts and move to the next corner. I would have preferred a PTO driven mixer, of course.

I bought pallets of 4000 psi quikrete and had it delivered with the posts. Several posts needed a lot more than 2.5 bags because I encountered many buried boulders so some of my holes were pretty big. I used Sonotubes in some of them, it worked OK.

 

[Egon]

Speaking of letting bags sit out. I saw a retaining wall a guy built by just stacking cement bags. Over time those bags hardened solid, and when I saw the wall the bags still had paper on them yet they were solid. Strange but true.

It's not uncommon to see bags of cement used for culvert rip rap.

 

[wroughtn_harv]

I mix the concrete. The reason I do so is I've been doing fencing for forty years or so. I've found that the dry set works best when doing a repair. I can take a twelve pound sledge and hit a post that was set dry set and the concrete will split top to bottom. The damaged post pulls right out. Mixed concrete on the other hand has to be dug out because it doesn't fracture so easy.

The toughest fence to set is in river bottoms out west where you have boulders and sand. The boulders mean the holes can't be done with an auger and the sand means you have to use water to keep it from caving in. If you're digging in sandy soil you water your holes as you go down and it won't cave in. Unless of course you use to much water.

Everyone wants to take the shortcuts. It's human nature. But every shortcut has its price. It would be nice to have a fence that looks like it was done right in the first place without all that work that doing it right takes.