Survivalist Forum banner

1 - 20 of 46 Posts

·
Forum Administrator
Joined
·
16,845 Posts
Discussion Starter #1 (Edited)
Which is better for fence post in wet soil, cement the post in or creosote?

In a previous thread we talked about using an auger to drill holes for corner post.

Well, in the past week or so we have gotten about 5 inches of rain. Within minutes of drilling the holes water started soaking in through the soil. Within 16 hours the corner post holes had filled in with 2 feet of water.

I fear pressure treated telephone poles will rot after a few years. To make the poles last longer, should I go with pressure treated poles that have also been dipped in creosote, or cement the poles?

The holes backfilled with water.


Tractor auger drilling the holes.

 

·
My Temperature is Right
Joined
·
5,578 Posts
Hey Kev,

It depends on how much moisture your soil gets in the desert it don't much matter. If your ground is pretty damp, concrete will hold moisture and the post will rot at the concrete. It's best to use preservative and tamp the soil good as you back fill. I do it that way anyway as I'm too cheap to buy sarkrete.
 

·
Forum Administrator
Joined
·
16,845 Posts
Discussion Starter #3
Hey Kev,

It depends on how much moisture your soil gets in the desert it don't much matter. If your ground is pretty damp, concrete will hold moisture and the post will rot at the concrete. It's best to use preservative and tamp the soil good as you back fill. I do it that way anyway as I'm too cheap to buy sarkrete.

What preservative are you referring to?

The post are pressure treated.
 

·
Freedom isn't free.
Joined
·
6,141 Posts
I read a book once on post and beam construction.

Creosote is probably a bad idea. Moisture will flow down into the creosote sealed part of the pole and be trapped there by he creosote. If you surround a post with concrete including the bottom, the water will run down the post and be trapped between the post and the concrete. The post will swell and might crack the concrete. If it doesn't crack the concrete, the water will stay next to the post, soak in and rot it out.

The book suggested leaving a path for the water to drain into the ground. Gravel as a footing with a concrete collar around the pole.

Alternative: Maybe a concrete footing. Set the pole on the footing square it up. Pour about 3"-4" of sand or pea gravel in the hole around the pole and then pour concrete on top of that. This leaves a space for the water that comes down the pole to drain out into the soil just above the footing.

I've concreted treated timbers into the ground for fences and rain barrel stands. I use the collar method and I mounded up the concrete on the surface so it slopes away from the timber. This helps it shed water away from the post. My rain
barrel posts are 11 years old and still totally solid. They get all the overflow from the rain barrels and that's a lot with our 4 months of rainy season.
 

·
Semper Vigilans
Joined
·
5,058 Posts
We just replaced a pier in a California bay that had been in for about 60-70 years.

When they pulled the pilings which were all creosoted poles they were all still solid.

That impressed me.

But I do like the idea of a concrete base as well, it should give stability for your corner posts.

.
 

·
Registered
Joined
·
2,582 Posts
Wood submersed in water does not rot. That's why, on those logging TV shows, you sometimes see divers harvesting wood from the bottom of rivers and lakes that is over 100 years old.

Anyway, here in central PA, the frost line is generally considered to be about 36" deep. So, when I'm installing posts permanently, I dig a hole that is ~42" deep and ~8" - 10" in diameter and add ~6" of pea gravel and set the post in the hole. I back-fill the hole with ~12" - 24" of the dirt and compact it to the point where the post won't move. Then I top it off with dry, quick-setting concrete. I will only add water to the concrete when it is in the hole and the concrete needs to have a finished appearance.

Here are some guidelines I follow when installing posts:
If you have to deal with frost, the post needs be installed below the frost line.
For every 3 ft of post height, a minimum of 1 ft should be in the ground.
I prefer cedar or aluminum over pressure treated posts. But, the budget and/or cost of material will dictate what will be used.
Concrete isn't always necessary for a permanent installation. All too often though, building codes require it.
 

·
Registered
Joined
·
84 Posts
here in Ireland where it is really wet we sometimes use concrete posts if ye have the money ye buy them or if yer short of cash ye can make them. The secret to getting the full strength is to vibrate the mix and to use some steel long bars at each cornery and wrap them with links every eight inches. They will last hundreds of years. On the west coast where they get twice the rain you will see a lot of posts with little plastic hoods tacked onto the top of the posts, its there to stop rain getting down the end grain afaik one last point is even if we are using 'lean-mix' (a weak dry mix) to erect posts we always drive the post into the ground a little way prior to tamping in lean mix, this creates a tube of concrete as opposed to a pot of conc that might trap water. One last thing that i have noticed is that most of the cheap treated white deel post (3" & 4") all failed at ground level! Not above it and not more than two inches below it.. it seems that constant wetting and drying at ground level just destroys the wood..
 

·
Pencil 5, AUTOCAD 0
Joined
·
3,660 Posts
Creosote or Cuprinol if it is still available... We just use cedar here with
rarely any rot, and it can be very wet here. What about putting in some
plastic drain pipe to get the water away from the area?
 

·
Registered
Joined
·
696 Posts
We just backfill with fist sized rocks. Pound them down hard with a tamping bar or something, they won't feel a thing. 8-12" of packed dirt or gravel in the top of the hole
 

·
Registered
Joined
·
348 Posts
I'm putting up a high game fence right now. We get about 55" of rain a year and our soil is sandy loam. My research has led me to use strainght concrete on all the corners. For my bracing post or stations if you will I'm using drive way slag and concrete collars. With the moisture we have and water table you have to do what you can. Treated post are not like they were. We fenced about 800 acres with 6" line post 5 to 7 years ago. They snap off about 6" above the ground. Painted t post rot same spot. My post are all galvanized. My corner holes were dug then we had a rain. The soft soil almost filled in one hole. I used 7 80 lbs bags on one corner 5' deep. The worst hole caved in so much when I cleaned it out I used 13 bags on that one hole. My line post and stations are going in now. 12" auger 39" deep 2 5/8 pipe 10 foot long 2' in the ground. I'm packing hydrated slag in the hole until I get my bottom elevation right. Then an 80 lbs bag of concrete for a collar then another layer of slag until I fill up to one sack will dome just above the ground level.
Im hydrating the lime with the rain and busting it up to stop it from lumping up. With out hydrating the lime and other goodies can make the slag swell and push the poles up.
 

·
Closed for the Season.
Joined
·
15,782 Posts
I would worry more about strength of the ground in your area than I would about rot using pt polls. If you have wet soil without a lot of rock than your posts are going to shift unless you have deep holes. Concrete will help some but it might not last good if you do not use one designed for wet locations.

With the size of polls you are using I would guess you need not worry about how long they last using. Probably your children (grandchildren) will have to eventually worry about replacing them.
 

·
Registered
Joined
·
348 Posts
When we bought pressure treated post for that big fence job you could definitely tell a Big difference in quality of the treated wood from Lowes and Home depot and the bundles we got from a pressure treated dealer up north. My river camp has some real crooked 4x6 thats treated. My 8x8 we got from a beach cabin area is definitely higher quality. Quality control is gone are the new process for treating is bad. Imo
 

·
Registered
Joined
·
696 Posts
I don't think it's necessarily the quality of the pressure treating, the cheap pt posts are all plantation grown very quickly. I've seen 6x6 with only 7-8 growth rings, no strength at all. The better ones are grown slower
 

·
Registered
Joined
·
348 Posts
I could easily used a small auger and 2 sacks of crete on my line post. These high tensil fences require less post and better corners. Going with the big auger im getting as much resistance as I can get with only 2' in the ground. A1 fence supplied a lot of my fence parts and they think im going a little over government specifications for airports. Im not drilling into high quality fill dirt. Just good fertile soil.
 

·
My Temperature is Right
Joined
·
5,578 Posts
What preservative are you referring to?

The post are pressure treated.
Creosote, pressure treating leeches out and the damn nematodes eat the wood. I see that happening to my garden squares. you'll lose about 1/32 - 1/16 inch off the surface a year without something the damn bugs won't eat.
 

·
Pour Encourager Les Autre
Joined
·
97 Posts
I don't think it's necessarily the quality of the pressure treating, the cheap pt posts are all plantation grown very quickly. I've seen 6x6 with only 7-8 growth rings, no strength at all. The better ones are grown slower
I agree the quality of the wood is extremely important. I check the end of every post or pressure treated pine board I buy. I am looking for pieces with lots of tight growth rings. You can really tell the difference when you pick up a piece because it will be much heavier than the quick growth trees. My philosophy is that the longer it took it to grow the longer it will take it to rot. They are also much less likely to warp in my experience.
 

·
Wile E Coyote, Genius.
Joined
·
33,708 Posts
1 - 20 of 46 Posts
Top