Lifespan of a fencepost?

[56FordGuy]

About two years ago, we had roughly 4 acres fenced with treated wooden posts, roughly 4x4", with rounded corners like landscape timbers. The holes were dug, and the posts were set in packed dirt. The field was empty for about a year and a half, and has had two horses in it for about six months. We checked today, and in that one field have 35 fenceposts that are either broken, or weakened to the point that lightly pushing on them with one hand causes them to start leaning and audibly cracking. Is this normal? At the time, we were assured the posts would be 'just fine' set in dirt, because they were treated and the dirt would be hard packed around them. Unfortunately, I don't really think 35 of them needing to be replaced after two years is 'just fine', but that's why I wanted to ask y'all. About how long should a wooden fence post last?

 

[clemsonfor]

About two years ago, we had roughly 4 acres fenced with treated wooden posts, roughly 4x4", with rounded corners like landscape timbers. The holes were dug, and the posts were set in packed dirt. The field was empty for about a year and a half, and has had two horses in it for about six months. We checked today, and in that one field have 35 fenceposts that are either broken, or weakened to the point that lightly pushing on them with one hand causes them to start leaning and audibly cracking. Is this normal? At the time, we were assured the posts would be 'just fine' set in dirt, because they were treated and the dirt would be hard packed around them. Unfortunately, I don't really think 35 of them needing to be replaced after two years is 'just fine', but that's why I wanted to ask y'all. About how long should a wooden fence post last?

Those things for some reason dont last long? I think there marginally treated for above ground, ground contact. I have some around my house that are pretty rotted forbeing treated. True 4x4's should easily last 20 years but a good cedar, locust or osage post will last a lifetime. Dont use those landscape timbers anymore. Use a cedar post every 3-4 posts or a 4x4 and then use metal t-posts inbetween, they will last a long time and you wont have to did a hole.

 

[magicheater]

A lot depends too on the humidity of your climate. I lived in Idaho when I was a kid and posts did not rot because it was so dry. The preservative is another factor. I have recently salvaged 6X6's here in Wisconsin that have been in the ground for 40 years and appear to be as new as the day they were put in. Using them in various projects now. Creosote was the preservative but has since been outlawed except for the utility companies, go figure.

 

[56FordGuy]

Those things for some reason dont last long? I think there marginally treated for above ground, ground contact. I have some around my house that are pretty rotted forbeing treated. True 4x4's should easily last 20 years but a good cedar, locust or osage post will last a lifetime. Dont use those landscape timbers anymore. Use a cedar post every 3-4 posts or a 4x4 and then use metal t-posts inbetween, they will last a long time and you wont have to did a hole.

We had a contractor put this fence up for us, and he selected the materials. I wasn't thrilled with the job when it was done, but had hoped it would last. Unfortunately, it looks like I'll be redoing a lot of it myself anyway. Should have done it myself to start with, but couldn't make the time to work on it.

I wasn't sure about using the timbers the first time, but was assured that they would be fine. No such luck. Looks like I'll be driving T posts and hand digging some post holes before too long.

 

[300UGUY]

A lot depends too on the humidity of your climate. I lived in Idaho when I was a kid and posts did not rot because it was so dry. The preservative is another factor. I have recently salvaged 6X6's here in Wisconsin that have been in the ground for 40 years and appear to be as new as the day they were put in. Using them in various projects now. Creosote was the preservative but has since been outlawed except for the utility companies, go figure.

I have some posts that are in very sandy soil, on a hill. They are in very good shape, after 30+ years. Same fence, down in the swale, the same posts didn't last 10 years. They were wet pretty much all the time, never got to dry out. One other thing, the top was solid down to 2 inches above ground, and the bottom was solid deeper than 4 inche or so. A 6 in piece right where ground and air come together was where it rotted off.

 

[RickB]

Species selection is important. For example, untreated Lucust will last 30-50 years in many situations. Of course after a couple years you need to drill holes for nails & staples.

 

[teg]

...fenced with treated wooden posts, roughly 4x4", with rounded corners like landscape timbers...

"Like" landscape timbers or were they actually landscape timbers? Those are not really made for direct burial. I think they are treated to 0.25 where normal pressure treated is 0.4 and marine grade pilings is treated to 0.8

 

[Jim Thompson]

Pressure treatment does not prevent wood from rotting under the right conditions. They are normally only treated to prevent damage wood destroying organisms- bugs. Now if creosote were still available, that's a different story.

Jim

 

[ridger]

i have 50 acres that has been fenced and cross fenced using treated 4x4 post and have had very little trouble.its about 25 to 30 years old.the soil is real sandy.i also have frontage road 1000+ feet all treated wood but i cemented the posts in and have never lost one.-+

 

[trailbuilder]

Landscape timbers here are made from Aspen which is very non decay resistance (rots quickly) They are the cores from making aspen plywood and that is why they are cheap. Other areas might have pine landscale timbers.

 

[whistlepig]

"Like" landscape timbers or were they actually landscape timbers? Those are not really made for direct burial. I think they are treated to 0.25 where normal pressure treated is 0.4 and marine grade pilings is treated to 0.8

Landscape timbers are not the same thing as treated fence posts. I have treated fence posts, set in concrete, that are still strong after 25 years. The only thing that I have seen rot them out quickly is if you cut the tops of them off. If you trim 6" off the top of a treated fence post it will rot out in less than two years.

 

[Mounted Madness]

Hmmmm. Coincidental to what I was doing today.

After putting the fence in 3 years ago with 9 foot treated 4x4's, then re-doing it last year (don't ask) with a post driver with 10 footers, I finally got around to trimming the tops off today, to correspond with the top of the fence.

As it turned out (the wind helped), I was able to enjoy the scent of the wood as I cut through the tops with the recip-saw. It was at that point that I realized that some of the treated posts were in fact, cedar, whereas others were spruce or some other soft wood.

I know I bought all the posts at one spot, and certainly didn't pay 'cedar' prices, so it proved once again that you can never be sure what you're buying, particularly if it's been treated, disguising the wood underneath.

If I'd known the supplier was selling treated cedar, I would have been a lot more selective when I was picking them out of the bin. :thumbsup:

 

[Mounted Madness]

Landscape timbers are not the same thing as treated fence posts. I have treated fence posts, set in concrete, that are still strong after 25 years. The only thing that I have seen rot them out quickly is if you cut the tops of them off. If you trim 6" off the top of a treated fence post it will rot out in less than two years.

Oh yeah, for the record, I'm going to Home Depot tomorrow to get preservative for the top of the cut posts. Thanks for reminding me...

 

[two_bit_score]

Put a little anchor seal on the tops and they will shed water forever

 

[ultrarunner]

In 1982 I redid a number of 6'fences using pressure treated posts from HomeBase... a chain like Home Depot.

Back then, each post came with a warranty tag and almost 30 years later I have not had a single post issue...

Too bad, the posts today don't have the same warranty and cost 2.5 times as much.

They were all set with concrete mix.

 

[riptides]

interesting topic.

I have been removing fence on my 100+year old dairy farm in areas. It is interesting to see the different types of posts that were used. Mixture of telephone (some carry the C&P tagging), natural cedar (rough cut), pressure treated (round, and square) and even T-posts.

Based on soil conditions around the property, the natural rough cut cedars have out lived all others. They sort of flake off in the ground contact areas. They get wobbly, but hold their own. The telephone poles are next up, but only due to their size. The pressure treated wood, held up well, but I doubt I'll find that treated material again. The T-post, well it should not be around a creek bed. Mother nature rearranged the creek over time and I have had to fish a lot out of the water. The rest of them just sort of fell over, freeze/thaw, animal and machine contact I imagine.

 

[jonyyuma]

Don't feel bad our landscape tembers did not last here either..Terrible fence post and terraced stacking did not hold up either? Maybe they just spray on the treatment, never did see any references to "Pressure treated"...But the price was way below, the cresoted fence post?

 

[dmccarty]

About two years ago, we had roughly 4 acres fenced with treated wooden posts, roughly 4x4", with rounded corners like landscape timbers.

When you replace the posts, check the top and/or bottoms if you can. All of the PT wood I have ever bought from Lowes, HD or better yet, directly from a PT company, as a label stabled to the end of the lumber. You might find the label in the post hole if you reuse the holes. The label has the PT treatment content. My guess would be that the wood used was treated at .20ish PCF and not rated for ground contact. The posts should be at least .40ish PCF or higher.

We have lots of Red Ceder here and I see it used for fence posts and even pole barns. The stuff rots out pretty quickly from what I can tell though it takes a good decade or two before the fence or barn completely fails. We looked at some property that had been owned by one family since the late 1800s. The guy selling was the last surviving sibling who had been born in the farm house his dad built in the early 1920's. They had numerous out buildings and barns using rock foundations and Red Ceder sill beams. Those barns were still in great shape because the ceder was not touching the ground. The rocks and ceder where found on the place.

Later,
Dan

 

[SPYDERLK]

When you replace the posts, check the top and/or bottoms if you can. All of the PT wood I have ever bought from Lowes, HD or better yet, directly from a PT company, as a label stabled to the end of the lumber. You might find the label in the post hole if you reuse the holes. The label has the PT treatment content. My guess would be that the wood used was treated at .20ish PCF and not rated for ground contact. The posts should be at least .40ish PCF or higher.
Later,
Dan

I agree. I think the treatment on those posts is light. Our green [pine] posts have lasted well at 12yrs and counting. Cedar seems to rot down to the heartwood in a few years and then stop. If the post has a big heart you can tamp it back tite and go a looong time. Were replacing the small hearted ones were having to remove with the treated pine driven down the same hole. They have moved away from the arsenic treatment to another preserver. I have no experience with how it compares, but Im hopin.
larry

 

[Gizmo2]

In 1982 I redid a number of 6'fences using pressure treated posts from HomeBase... a chain like Home Depot.

Back then, each post came with a warranty tag and almost 30 years later I have not had a single post issue...

Too bad, the posts today don't have the same warranty and cost 2.5 times as much.

They were all set with concrete mix.

Same here, 25 years old http://www.tractorbynet.com/forums/attachments/projects/146222d1258730980-board-fence-img_3949_1.jpg
I would not want to look for stuff today that would last 25 years.