Fence posts

[yogifink]

We're fixin to set a couple fence posts and I was wondering what you all thought about coating the posts before putting them in the ground. The lumber is PT. We set a few (about 50) treated post about 2 years ago and have had 3 or 4 rot out. My neighbor (old timer) said that they use to coat posts with tar before they set them in the ground and would periodically pour some kind of oil, probably used motor oil, at the base of the post to help keep them from rotting.

I am not an advocate of putting tar in the ground where I am planting food and am obviously not going to pour motor oil on the ground, just wondering if there was any merit to this.

 

[my sunwolf]

If you don't want to coat, you could try getting some nicer quality wood--people around here use untreated locust and walnut for posts and exposed barn (with roof), and it lasts a good deal longer than 2 years. Though it gets expensive.

You sure nobody lied to you about whether or not those posts were treated? And have you pulled them up to see if any insects have gotten to them?

I've heard of some home-made mixtures but never tried any, so can't be any help there

 

[yogifink]

Yeah, I would love to go the route of some hard wood, but I don't think its an option. We live in pine forest. Every so often you see a ceder, but if I cut one of them down its going to be a chest, not a post .

I would assume that it would have been termites that got to the few posts that went - but I thought pt wood was also treated with an instecticide?

 

[Ashdoes]

From what I've read, painting the bottom with tar keeps the buried wood from absorbing water and rotting. When we bought our home, we had to pull up a bunch of post, and quite a few of them were rotted and splintering.

 

[R2elk]

We're fixin to set a couple fence posts and I was wondering what you all thought about coating the posts before putting them in the ground. The lumber is PT. We set a few (about 50) treated post about 2 years ago and have had 3 or 4 rot out. My neighbor (old timer) said that they use to coat posts with tar before they set them in the ground and would periodically pour some kind of oil, probably used motor oil, at the base of the post to help keep them from rotting.

I am not an advocate of putting tar in the ground where I am planting food and am obviously not going to pour motor oil on the ground, just wondering if there was any merit to this.

Where I am termites are a very real problem. I have a shed built on old treated telephone poles and one of the poles has been completely eaten off at ground level by termites. On the other hand the split rail fence with its untreated cedar posts are slowly rotting off after over 30 years of being in the ground. In the last 10 years I have only had to replace about 6 of those posts.

 

[UgLeeDuck]

Old/Used engine oil.

I've just seen this and wanted to add that this was standard practice for all wood/lumber that was used in agricultural buildings when i was growing up. Soaked or painted in the used engine oil that you gained whilst servicing any vehicles you had. Note the word used.

The same oil was used to paint wooden spade/fork/shovel handles during the winter.

A box of sand was soaked with the engine oil and this was used to clean/rust-proof tools after you'd been using them. Just dunk it in as if digging with it and hey-presto out it comes cleaned and oiled ready for putting away until next use.

I was a mechanic by trade and used to be able to get used engine oil in vast quantities when i needed it so I used this old practice. Very good annual treatment for any standing wood that had to face the elements. I believe this is still the practice in some rural areas of Europe and former soviet block countries.

 

[newfoundland]

We wrapped the bottom of the posts in the plastic that haylage comes in. It was a good way to recycle the plastic and has been most effective in keeping the posts dry. Didn't cost a thing either.

 

[Ole and Lena]

I've worked in the utility pole inspection business. Treated wood varies in quality. Many of the landscape timbers available are treated too green or are too resinous when treated so they do not take the chemical. Your treated posts should be waxy looking, not dry and cracked (sign of poor penetration). Buy from a reputable lumber yard or farm store, not Lowes or Menards. I've also had really good luck with recycled utility poles. You want the old creosote treated cedar or southern yellow pine ones, not the green or brown pentachlorinate or AC2 poles. The creosote poles will rot up the center eventually but retain a good solid shell for many years. When you cross section one you'll see the ring of creosoted wood about 1-2" thick. Wrapping them with plastic as suggested above will trap moisture inside and hasten rot.

There are commercial wood treatments available, but most are registered pesticides for industrial use. You can however use pine tar (available in the horse care section of the farm store). Dissolve it in gasoline to make a thick syrupy liquid and paint it on warm. Allow it to cure in a dry sunny location. Do a few coats on everything that will be below ground level.

Especially in warm wet climates, nothing buried in the ground will be rot proof. Inspect your posts regularly for signs of termites and treat immediately by drilling small holes and applying a termite specific insecticide. Plug the holes with small cedar sticks. If all else fails, talk to your local Nat Gas company or well driller and see if you can get some scrap 4" steel gas pipe or well casing. A little hard to work with, especially if you're making electric fence, but they don't rot and if you fill them with sand and lime they set up REALLY solid.

 

[debgal]

My grandpa, rip, would mix up 50/50 Lin seed oil and turpentine. Coat the post, dig a hole, done. Those fence post are still there to this day. I use this method. I get large branches, mix up a batch and set the pole in the night before. Wha lah. Hope it helps

 

[Eddie Chestnut]

I just had to remove 7 fence posts. First 3 years ago the 4x4x 6ft posts were put ina hole and cement was poured around the post. Over time time termites got to the wood posts and the cement just cracked in half. The bottom of the posts, about 16 inches were all eaten by termites, looks like the 4x4 post was put in a pencil sharpener, riddles with holes, rotten. I think if you fill a bucket with johnson water repelent? and Watco wood coating would help a lot. Watco is a plasticizer and wicks into the wood. Johnson water repelent will help draw the Watco deeper into the wood. My guess. But just painting will do nothing. The wood posts will just rot out. Any wood that touches the ground will get eaten by termites.

Eddie