Protection of fence posts?

[JHZR2]

We replaced a fence on our property maybe 12 or so years ago. Two main posts on the longest section rotted at the surface or just below. All the rest are fine, at least for now.

We changed them out. Put tamped gravel in the bottom to help with drainage. There wasn’t much in there from when the company installed them.

Is there anything that should be done for the posts to protect them more, before we fill the holes and tamp in all the soil?

 

[burbguy82]

We replaced a fence on our property maybe 12 or so years ago. Two main posts on the longest section rotted at the surface or just below. All the rest are fine, at least for now.

We changed them out. Put tamped gravel in the bottom to help with drainage. There wasn’t much in there from when the company installed them.

Is there anything that should be done for the posts to protect them more, before we fill the holes and tamp in all the soil?

I would try diesel fuel or used motor oil soak, maybe drill a hole at ground level, and inject? Kerosene?

BTW, you cant tamp gravel....I mean you can, but you are no doing much.

 

[doitmyself]

Woodlife CopperCoat Green is the only wood protector I am aware of that still has some ability to protect against fungal and insect rot.

Wood tends to rot just below the ground surface because that is the best environment for fungal growth - moisture and air.

Cedar, black locust, and of course pressure treated tend to be the best post material.

 

[Cujet]

I used multiple bags of concrete to set the wooden fence posts. They still rotted above the concrete. Creosote used to be the standard for protection.

Of course, oil based products can work.... I've strongly considered a method of dipping fence posts into used motor oil, like a section of PVC pipe, and applying a vacuum via my vacuum pump, to help infuse the wood.

I used copper based wood "green products" copper green wood preservative available at Lowes, and maybe Homeless Depot. It seemed to work fairly well on my shed's wooden floor. No bugs, no rot.

 

[cptbarkey]

I might be done using 4x4s as fence posts and next time going with galvanized

 

[Nukeman7]

We replaced a fence on our property maybe 12 or so years ago. Two main posts on the longest section rotted at the surface or just below. All the rest are fine, at least for now.

I had the same situation with numerous ground contact pressure-treated 4"x 4" fence posts professionally installed 13 years ago. I think it is the nature of the EPA compliant chemicals that have been used since arsenic was banned decades ago.

We changed them out. Put tamped gravel in the bottom to help with drainage. There wasn’t much in there from when the company installed them.

Is there anything that should be done for the posts to protect them more, before we fill the holes and tamp in all the soil?

When I replaced the posts in 2023 & 2024, I sprayed the below ground sections with non-rubberized undercoating (essentially tar in solvent) and let them dry overnight before anchoring them in 8" cylindrical concrete forms protruding 1" above ground level. I have no intentions of replacing them again in my lifetime.

 

[JHZR2]

I would try diesel fuel or used motor oil soak, maybe drill a hole at ground level, and inject? Kerosene?

BTW, you cant tamp gravel....I mean you can, but you are no doing much.

The local utility did that with all the telephone poles a couple mod years ago. They all have a plug with a big torx head drilled into them at an angle, that they must have injected something. They also dug around all the poles and put what looks like wax paper around them….


I know there isn’t much you can do to tamp gravel, but it works the first layer into the soil, and just ensures that the rest is well aligned with the other pieces. Not a big deal.

I might be done using 4x4s as fence posts and next time going with galvanized

That was one of the recommendations I saw. Not a bad idea, except that we were keeping our other posts, and the spacing was based upon it. While there may be a better way, this is great for now.

Woodlife CopperCoat Green is the only wood protector I am aware of that still has some ability to protect against fungal and insect rot.

Wood tends to rot just below the ground surface because that is the best environment for fungal growth - moisture and air.

Cedar, black locust, and of course pressure treated tend to be the best post material.

the fence is cedar, I suspect the old post were PT, and certainly the two new ones are.

 

[samven]

I had the same problem. The gate posts went first then about 3 or 4 posts would break every year after that. They were all set in concrete and I cursed the installer everytime I had to dig one out, and now refuse to put a post in concrete. It may not stop them from rotting but they are a lot easier to pull out and replace now.

 

[Cropduster172]

I saw this video awhile ago. Although I don't think I've seen any products like it in JD or Lowe's.

 

[Lubener]

Just being pressure treated doesn't mean it is meant for direct ground contact. There is post lumber which is meant for that purpose. I suspect yours isn't meant for ground contact. Applying a sealant is not a long term solution.

 

[rszappa1]

I have 34 total fence posts in my back yard and what I have done is spray the area around the base of the wood post and the ground with some rubberized undercoating that I get at Wal Mart.....Some of my posts have been in the ground since first installed in 1999 and are still doing fine....

 

[V70tdi]

I newer put any kind of wood in the ground or in concrete. Use this kind of galvanized metal to set the wooden post

 

[nomas]

There's no one answer to the problem . It depends on your soil type and the environment around it . I've seen PT posts last for decades and some that rotted away in the ground in 10 yrs . We changed out galvanized fence posts at work that had crumbled away to nothing and others at different locations were as old as me . I've always felt that putting gravel in the bottom of a hole just created a basin to collect and hold water . Especially if you have clay soil .

 

[JHZR2]

Just being pressure treated doesn't mean it is meant for direct ground contact. There is post lumber which is meant for that purpose. I suspect yours isn't meant for ground contact. Applying a sealant is not a long term solution.

These are specifically, posts for fencing. Not just some random 4x4.

I newer put any kind of wood in the ground or in concrete. Use this kind of galvanized metal to set the wooden post

I actually used that for my mailbox. It has held off rot, but it is not as strong/sturdy.

I have 34 total fence posts in my back yard and what I have done is spray the area around the base of the wood post and the ground with some rubberized undercoating that I get at Wal Mart.....Some of my posts have been in the ground since first installed in 1999 and are still doing fine....

That’s a good idea! Kind of like the shrinkwrap product.

I saw this video awhile ago. Although I don't think I've seen any products like it in JD or Lowe's.

Neat idea, a little bit late for me this time. Thanks for the idea! I think the rubber undercoating may be worth a shot…

 

[mdtn952]

Long term you will benefit from some type of durable covering/cap for the top of the post...thats where things will start to really deteriorate over time.

 

[Nukeman7]

Neat idea, a little bit late for me this time. Thanks for the idea! I think the rubber undercoating may be worth a shot…

I specifically sought out the tar-like non-rubberized coating for my fence posts. Everytime that I have used the rubberized undercoating on the undercarriage of a vehicle, it eventually peels away after several years. I suspect the same thing will occur on the 4" x 4" post and create a pocket to accumulate moisture. The non-rubberized coating stays tacky and doesn't ever peel away.

 

[JHZR2]

I specifically sought out the tar-like non-rubberized coating for my fence posts. Everytime that I have used the rubberized undercoating on the undercarriage of a vehicle, it eventually peels away after several years. I suspect the same thing will occur on the 4" x 4" post and create a pocket to accumulate moisture. The non-rubberized coating stays tacky and doesn't ever peel away.

Roofing tar, then? Not sure I’ve seen non rubberized, tar-like undercoating.

 

[SC Maintenance]

I had the same problem. The gate posts went first then about 3 or 4 posts would break every year after that. They were all set in concrete and I cursed the installer everytime I had to dig one out, and now refuse to put a post in concrete. It may not stop them from rotting but they are a lot easier to pull out and replace now.

If your re doing the fence anyway, just set the next post right by the first to the side.

If you do it before the break off you can sometimes pull them with a high lift. My experience is you have to drive some screws in to hold the chain from slipping. As always, be very careful with these jacks.

 

[SubieRubyRoo]

Roofing tar, then? Not sure I’ve seen non rubberized, tar-like undercoating.

A 5-gal bucket of asphalt sealer? Let it sit in the sun and get hot, then dip the bottom 2’ or so of the post into the bucket, let it dry. Then once it’s dry stick it in the hole? Just a thought.

 

[Mcbeem5]

If you have several bad fence posts on fence line these work.I just installed this repair kit on 2 fence post rotted at ground level. Available on amazon some are as thick as 1/8" steel.Really firmed up fence and surprisingly easy to install! Many options from .085 thick steel to .119 thick steel.