Fence post help

[expat]

I will be helping a friend replace some fence posts in his yard.
The problem is, the old posts were set in concrete and the post backfilled with about 10" of top soil. The post has rotted above the concrete.

I do not really want to dig the concrete out, the location makes this difficult. I thought of boring the old wood out of the concrete and slotting in the new post, but that might not be easy either.

Ideas please.

 

[PimTac]

New posts in new holes in between the old ones.

 

[KJSmith]

I did what PimTac said.
Moved the post over about a foot.

Grabbed the top of the old post and snapped them off below ground.

 

[Boomer]

I used to have about 200 feet of split rail fence for 30 years. The pressure treated posts would always rot through right where they entered the ground. I never use concrete. What I did that made replacement easy was to soak the base of the new fence post for about two days in a five gallon bucket of used oil. Then I would put it in the hole and fill the hole with pea gravel to within about 2'' of the top of the hole. Covered the gravel wit some soil, planted grass seed and there it was. When it would rot off some years later, it was easy to remove and the gravel was easy to remove and reuse.

 

[maxdustington]

If you do new posts you have to change the configuration of the fence. If it's a new fence, sure but if not you have to yank them.

My Dad taught me a cool trick: Dig enough to free them, then wrap the stub of the post in a chain and the other end around a chipping bar and lever them out. If you can't do that, you have to break them up with a demo hammer. Hopefully there is something left to grab onto.

I'm going to assume they did them to code and there's a four foot concrete footing under the ground.

Don't try to re-use the old footings, that's horrible craftsmanship and will not last. I have a feeling they will break free and heave like the footing isn't even there.

The hardest part of the job is making sure your measurements are good and the new posts line up with the old fence.

 

[maxdustington]

Originally Posted by Boomer
I used to have about 200 feet of split rail fence for 30 years. The pressure treated posts would always rot through right where they entered the ground. I never use concrete. What I did that made replacement easy was to soak the base of the new fence post for about two days in a five gallon bucket of used oil. Then I would put it in the hole and fill the hole with pea gravel to within about 2'' of the top of the hole. Covered the gravel wit some soil, planted grass seed and there it was. When it would rot off some years later, it was easy to remove and the gravel was easy to remove and reuse.
Building code in Ontario requires four foot concrete footings due to frost heaving.

 

[PimTac]

Originally Posted by maxdustington
Originally Posted by Boomer
I used to have about 200 feet of split rail fence for 30 years. The pressure treated posts would always rot through right where they entered the ground. I never use concrete. What I did that made replacement easy was to soak the base of the new fence post for about two days in a five gallon bucket of used oil. Then I would put it in the hole and fill the hole with pea gravel to within about 2'' of the top of the hole. Covered the gravel wit some soil, planted grass seed and there it was. When it would rot off some years later, it was easy to remove and the gravel was easy to remove and reuse.
Building code in Ontario requires four foot concrete footings due to frost heaving.

Is the concrete footing mandatory? I understand the frost heave situation but I'm wondering if the previous suggestion of using gravel would be okay.

Sinking posts into a concrete base usually ends up as the op has described. Rotted posts that break off at the concrete.

 

[maxdustington]

Originally Posted by PimTac
Is the concrete footing mandatory? I understand the frost heave situation but I'm wondering if the previous suggestion of using gravel would be okay.
If you're not getting it inspected than you can do whatever you want. If you're going to charge someone to install their fence posts in the province of Ontario, then that is how it must be done.

They usually don't break off flush with the concrete, there is a stub that you can grab on to most of the time. I'm not a fence carpenter but I've done a few.

 

[ecotourist]

I had a fence post set in concrete that had been partially destroyed by carpenter ants and had cracked at ground level. There was just enough to get a hold of and I managed to pull it out cleanly using a jack. It was nip and tuck whether it would come out without breaking. But then the hole had slightly different dimensions than the new post. So I had to shave down one side of the post, and then had a small gap in the other direction which I filled with gravel. It worked well enough but I wouldn't do it for a whole row of them.

Unless you have to use concrete I'd just set new posts in pounded dirt or gravel. They might even last longer and they would certainly be easier to remove when (not if) they rot off again.

 

[andyd]

I use a bumper jack to pull steel fence posts. Wood gets stone rammed in beside it. Setting wooden posts in cement just ensures, that they will rot at grade level . I keep all rocks I remove from soil to ram down post holes with an old pick handle and such. Why use cement?

 

[ecotourist]

Originally Posted by ecotourist
I had a fence post set in concrete that had been partially destroyed by carpenter ants and had cracked at ground level. There was just enough to get a hold of and I managed to pull it out cleanly using a jack. It was nip and tuck whether it would come out without breaking. But then the hole had slightly different dimensions than the new post. So I had to shave down one side of the post, and then had a small gap in the other direction which I filled with gravel. It worked well enough but I wouldn't do it for a whole row of them.

Unless you have to use concrete I'd just set new posts in pounded dirt or gravel. They might even last longer and they would certainly be easier to remove when (not if) they rot off again.

When we lived in Saskatoon I built a new fence with cedar posts set in pounded clay. We lived in that house for 10 years and the posts were still solid when we left. And Saskatoon has high winds, high enough to take off roofs and blow down poorly made fences in our neighbourhood.

 

[nwjones18]

I did this method except I dug around the top of the concrete and put the chain around that. Is a real pain, but the best method I've found.

https://www.youtube.com/watch?v=b_9-6DgsN3Y

 

[expat]

Originally Posted by maxdustington
Originally Posted by Boomer
I used to have about 200 feet of split rail fence for 30 years. The pressure treated posts would always rot through right where they entered the ground. I never use concrete. What I did that made replacement easy was to soak the base of the new fence post for about two days in a five gallon bucket of used oil. Then I would put it in the hole and fill the hole with pea gravel to within about 2'' of the top of the hole. Covered the gravel wit some soil, planted grass seed and there it was. When it would rot off some years later, it was easy to remove and the gravel was easy to remove and reuse.
Building code in Ontario requires four foot concrete footings due to frost heaving.



That is one reason I live on the West Coast

Thanks for the ideas guys

 

[PimTac]

I would go the gravel route then. Did the hole, add a layer of gravel for drainage and set the post. Fill the hole with gravel, tamping it down as you go. That way the rain water drains in past the wood. The used motor oil suggestion is also good. I've done that in the past but that is up to you.

 

[Shannow]

I'd dunk them in used antifreeeze for a week....
https://www.boatdesign.net/threads/ethylene-glycol-as-a-wood-preservative.17739/

 

[ecotourist]

Originally Posted by PimTac
I would go the gravel route then. Did the hole, add a layer of gravel for drainage and set the post. Fill the hole with gravel, tamping it down as you go. That way the rain water drains in past the wood. The used motor oil suggestion is also good. I've done that in the past but that is up to you.

We always set the post onto a stone at the bottom of the hole as well.

 

[Kjmack]

OZPOST