Vinyl fence posts

[Salty]

Looking for opinions on cementing these into the holes.
Would you think there is a need to have anything in the center of the post below grade, like gravel or cement?
The more popular process seems to be poring quick setting concrete dry around the post and either add a gallon of water or just let the moisture from the ground harden the cement.
My thinking is that the weekest point is going to be at grade level regardless of what is inside the post.
I'm not really concerned anout wind shear as the 6x6 panels will be somewhat protected from the house on 1 side and plenty of trees on the other.

[gjat]

Hold a pencil in your fist vertically. Use the other hand and move the top part of pencil back and forth. You will see there is 'moment' (force) at grade (pivot point) and at the bottom. What you want to do with a foundation is transfer as much as that force to the surrounding soils. It depends on your soil conditions.

If your soil conditions are clay/rock and very dense and stable, then concrete at the top will suffice. If soil is sandy/loamy/loose, then you want to replace as much disturbed soils with concrete backfill to increase the soils degree of friction and the surface area of the load being applied when the wind blows on the panels.

[iceman61]

Pouring dry quickrete around the post is the way most people I know do it also. my fence has been standing for 10 years now & just 3 months ago my neighbor's fence got blown down. He even had about a square of shingles blown off his house. It's easier to keep your fence post plum going the dry way.

While my fence is not vinyl, I remember a friend installing one & he told me he used 4x4 treated posts & slid the vinyl posts over the 4x4's. I don't know if that helps in your situation or not.

[Seedy]

Around here, they fill the posts with sand to stiffen them.
-Craig

[crokett]

I think I would either pour wet concrete into the hole then push the post into that, or assuming the post is not capped set the post in the hole then pour wet or dry concrete down inside the post.

[jgscott987]

I don't know much about the subject, but I believe it is standard practice to include a PT 4x4 inside the vinyl post. I believe they are generally sized for exactly that. Filling it with concrete or sand would achieve the same purpose I guess. Don't know which would be easier and/or cheaper...

[Salty]

This is from the blue box website:
1.
After the gravel is added, fill the hole with concrete. A quick-setting variety can be used to speed the process, but be sure to follow instructions for how long the concrete should set.

2.
Tap the hollow post into the concrete so the concrete fills the center portion of the post in the hole. Tap the post down to the top of the gravel. Plumb and level every post. Overfill holes at the top. Using a trowel, slope the concrete away from the post to prevent water from collecting around it.

Now I had given this some thought earlier and initially I was going to mix the concrete for each hole in a wheelborrow and pour it in. That way I could indeed push the post down and it would fill the inside as well. While I still believe the most stressed point would be at grade level, it would also be possible for the side to buckle in if there is no support in the center.
Then I read the directions for the quick setting concrete and it says to pour the dry mix around the post and add water. The sale flier also shows this being done on a vinyl post. That won't get it into the center unless the post is moved up and down to allow the wetted mix to seek a level and thereby fill the center. But this is assuming that just adding the water at the top of the dry filled hole will make the mix flow enough to allow you to move it up and down. I doubt you could push it back down once you pulled it up. If you could, then you would have to add more to the outside and more water and ........this seems to be more work than mixing it in the wheelborrow! I'm sure that filling the hole with a wet sloppy mix would allow me to push the post down to the gravel base.
I'm NOT keen on dumping sand or concrete (wet or dry) into the post 6 foot up while on a ladder!
Seems to be a lot of conflicting information available so I think I'll go with my original plan.
Fortunately, only 7 of the 15 holes will be for the 6 ft privacy sections. The rest will be 42" picket style.

I also don't like the idea of filling the hole above the grade and sloping the concrete to prevent water fron collecting around the post. Directions on the concrete say to fill the top 3-4 inches with sod. But then there is the fact that if water gets between the post and the cement, then freezes...well then it will break away. Or would it? Would there be enough flex in the density of the vinyl to allow the water to freeze and expand without forcing a break?
Me thinks I am thinking about it too much!

Thanks for all the input folks.

Salty

[Mr__Bill]

A few years ago I watched the progression of a vinyl fence being installed. Each night I walked the dog by and checked out the project. In this case a footing was poured the full length of the fence and at each post a 3" stub was poured in some kind of a plastic form with a length of rebar or rigid electrical pipe for lanterns sticking out. The next day or so they planted the plastic posts on the stub and filled the post with concrete. It made a very sturdy fence with a light on the top of a post every so far along it. I have no idea of how deep the footing was and I expect that for a residential fence it's a bit overbuilt. I also feel that replacing a damaged post would be difficult. However the gateway in the fence was very sturdy with none of the wobbly wiggly that fence gates tend to have.

Just a bit more conflicting concepts to add to the confusion.

Bill who believes that good fences make good neighbors, especially if the neighbor pays for it