The next few days are not going to be fun

[Jstpssng]

So are you saying that you still set them in concrete but just do it differently or that you do something else?

The OP, bdog, is somewhere in Texas and frost heave will not be the problem I'm pretty sure. But what do you do in Maine?

You need to dig below frost line, and pour into sona tubes as the OP plans. I've also seen heavy plastic wrapped outside the pour, so that frost has nothing coarse to grab onto.

 

[radios1]

WoW!! Your mixer will hold 16 bags. I have a stand alone mixer that will hold 4 bags and it's a real PITA if you don't have a helper. Helper either tips the mixer or holds on to the wheelbarrow.

as they say, Everything is Bigger in Texas!.. that's why his holds 16 bags..

 

[Gary Fowler]

You wouldn't do that here, unless you like having frost lift them out of the ground. My father did that once with a greenhouse; the next year he had to dig out around them and chip away the concrete. The greenhouse was 96' long, and the posts were 4' OC!

If you can put it in wet, you can put it in dry. Just do it the same way. There is usually enough moisture in the ground to hydrate the concrete. If your father did it and got frost heave, then he would have gotten heave with wet mix also if he did it the same way.

I have concreted in post and 20 years later took down the fence and chipped off the concrete. The post were still like new. The way I do it is put some dry mix in the hole, then set the post and fill the hole with dry mix, add water to the top and work it in a foot or so with a rod. Get a good 4" slump mix developed and then mound it up around the post so the concrete is higher than ground level and sloped off to the outside edge. Rainwater then runs off the post and doesn't penetrate into the core. What little moisture that does will hydrate into the concrete and the post will essentially stay dry. You must use pressure treated post.

 

[Jstpssng]

If you can put it in wet, you can put it in dry. Just do it the same way. There is usually enough moisture in the ground to hydrate the concrete. If your father did it and got frost heave, then he would have gotten heave with wet mix also if he did it the same way.

I have concreted in post and 20 years later took down the fence and chipped off the concrete. The post were still like new. The way I do it is put some dry mix in the hole, then set the post and fill the hole with dry mix, add water to the top and work it in a foot or so with a rod. Get a good 4" slump mix developed and then mound it up around the post so the concrete is higher than ground level and sloped off to the outside edge. Rainwater then runs off the post and doesn't penetrate into the core. What little moisture that does will hydrate into the concrete and the post will essentially stay dry. You must use pressure treated post.

I never said anything about wet vs drymix, I was referring to just pouring into the hole which you dug.

 

[mred2]

I live in Alabama, no frost heave. But I do understand that you must have holes at least deeper than the frost and and some parts of the country that may be over 24 inches. I have read that if the hole has smooth sides the frost does not have anything to grab on to. So the tubes are recommended.

 

[RalphVa]

I never premixed concrete for posts. Just pour the stuff into the hole around the post, pour in some water and let sit.

Ralph

 

[Steppenwolfe]

To set fence posts, we put the mix in dry. Pack it down to keep the post straight and come back after a week. If in the dry part of summer, we will pour water in the hole. I have had post last 15 + years set in concrete.

Yep... :thumbsup: done that for many years. The concrete will draw in the surrounding soil moisture and cure perfectly.

 

[grsthegreat]

I mixed that much by hand every year when i was installing generators. About 8-10 bags per gen pad i set. Not worth cleaning a mixer for 8 sacs, so i just used wheelbarrow. Last year i set a heck of alot of 6x6 treated in concrete fencing 10 acres for the horses. My old fence posts are over 20 years old and still strong .... i lost a few 4x4 post over the years, do i never so smaller than 6x6 now.

Ive had great luck concreting in fence posts over the years...even though some people swear that they will rot off. I always mound concrete up higher than soil base to prevent pooling.

But i do hate concrete ....always have.... always will.

i never used dry set fence posts...... just a personal thing.

 

[Ortimber]

Drop the post in the hole, add about a gallon of water, add concrete straight from the bag. Unless you really want to, I don't believe there's any reason to mix the concrete before putting it into the hole.

 

[MossRoad]

We've never dug down below the frostline for fence posts set in concrete. That would be 4' for a 4' post here. We just don't do it. We dig 2' for a 4' post. 3' for a 6' post and 4' for an 8' post. We use an inverted V shaped hole that is wider at the bottom than it is at the top.

What seems to happen with frost heave on fence posts with a V-shaped blob of concrete that is wider at the top than it is at the bottom, is the frost lifts the post and concrete, the dirt settles in the voids all the way down the sides of the V, and the post is a little higher each year. If it's wider at the bottom, there's an extremely smaller footprint for the frost to lift. Think about it.

A cylinder that's 8" in diameter by 24" deep is around 180 square inches of surface area on the sides of the cylinder, if it's a V-shaped tapered hole, plus the bottom of the cylinder. Say 6" at the bottom. 3x3x3.14= 28.26.

So, about 180 + about 28 = about 200 square inches for the frost to grip.

Now make that hole an inverted V shape. 8" at the bottom and 6" at the top.

4x4x3.14 = 50.24 square inches for the frost to grip on the bottom of the hole.

So you have about 200 square inches of frost grippable surface VS about 50 square inches of frost grippable surface. That's about 4 times the surface area.

It won't grip the side of the slope very well on an inverted V shape.

Also, an inverted V-shaped hole that's wider at the bottom puts more mass around the post lower, which helps keep the posts from tipping or pulling out once the dirt is filled back on them.

So there you go. Hope that helps some folks.