Like I am sure a lot of people here on HEF have found out since they started making everything 'Green' is it just doesn't last any more.... So does anyone have any suggestions/tips on what to use to give additional protection to ground contact rated posts? I have seen guys soak them in everything from used motor oil to all kinds of mixes of oil waste products... but does it help? any one here done anything similar a ways back and are the posts still going strong? We put in all kinds of 'pressure treated' lumber for support posts,fence posts, pole buildings, etc... and I keep seeing them fail miserably : here are some pics of a fence line with 4x4 treated posts every 50 feet that went up 4-5 years ago... over 90 percent of them have rotted off and needed to be replaced starting around 3 years ago Or does the 'Ground Contact' rating only mean that the post can come in contact with dirt and not be immersed in it...
I wonder what they were treated with, maybe just a nice ride home.
ground contact is just that, the post lays on the ground, not in it..I have used brush on tar to coat posts and let it dry then buried, I have many in for a few years with no sign of rot, I have the older treated posts before they went to the copper junk that are 20 to 25 years old and show minor signs of decay as fence posts..they dont make them like they use to..
I use black locust posts, in the wet areas. Generally they will last 30-40 years, 'round here, then you pull and flip over, and get another 20 outta 'em...
For fence corner and brace posts we use new railroad ties, all the rest are steel T posts, as for buildings, like pole sheds and things, we don't use treated anything anymore, we pour cement footings and walls and set the posts on those above ground. As for treated lumber or posts, we have yet to find anything that is good anymore. We gave up on using treated posts for fences, they don't last long enough in my area from the time you set them in to even hardly get the wire stapled onto them before they rot off and fall over, LOL. If you know someone who works for a power company, many of the old poles they take out will still last decades for fence posts, its what a lot of guys use around here for posts, nothing new pressure treated is worth taking home let alone install and actually use. As Diydave said, many have gone to sawing down certain tree's and using those for posts. Others still have gone to using plastic posts, made from a recycled plastic and claim they are the best option today, I know a few that after those hollow plastic posts are installed, they fill them with concrete and rebar, others are made of solid plastic and look like a regular wood post, never used any of those myself. For corner and brace posts, several I know have forms they made and dig a hole as you would for putting in a wood post, set their forms up and pour themselves concrete posts, similar to a survey or section marker, my farm has these on it for boundary fences, those cement posts are over 100 years old, several are also section markers and have a metal plate cemented into them that has the section criteria stamped onto them.
I'm running an experiment. Every post that has failed was rotted at the ground line. The portion in the ground is solid and a pain to get out of the hole. I've wrapped some black plastic (polyethylene) about a foot wide at ground level. (easy.. staple the start & finish) The sun breaks down the exposed plastic, so I trim it off with a razor. Protected from the sun, poly will last forever. 5 years so far.
I WISH they used concrete posts as boundary markers HERE.. my neighbor keeps moving mine.. When I was building my fence..straight PT posts w/ rocks in the holes[bottom & sides] he came out to see what I was doing.. I told him, "heres the marker.. I'm going 10 FEET OFF THE MARKER to my side".. "that way, I can mow the grass behind the fence".. "He" put up a "mulch" berm..moved the marker & now the "berm" has encroached on my property..[wash out] .. he's a COMPLETE A**HOLE.. ANYWAY.. back to the plot.. I used PT fence post & filled the holes w/ rocks, bottom & sides for drainage.. been fine for over 10 years.. They GOTTA drain.!!!
Ground contact is not the best grade of pressure treating. Maybe "structural"? the retention is something like .40 for ground contact, .60 for a better grade and might go up too. I'd have to look it up. A couple of old time methods I've heard, char the outside of the post, and plant it upside down.
There is a "marine" grade of timber that you might be able to get with a lot of looking. It uses the old school insect/rot proofing that is not allowed for typical use. Rick
Creosote..?
Back before they wrecked everything fence posts and green board were treated with CCA, Chromated Copper Arsenic. My impression is it should still be available for ag use. Around here we use round posts for fences like you showed. https://www.fbibuildings.com/getting-started/resources/lumber-preservatives-cca-vs-acq-equal/
As for what trees last longest, Osage orange is flat out the best, then black locust, then white oak. Mulberry and cherry will last as long as today's PT pine. Also, if its wet, backfill with pea gravel improves brainage, and keeps water away from the post. There are lots of post protectors, on the market, too, but most are for 6x6's...
Thanks for all the suggestions guys I have seen concrete posts used once in a while might have to look into making some 'precast forms up' although they would be heavy as heck... so much for installing by hand some of the ones I have seen look like a tall skinny obelisk, might have to get a picture one of these days and put it up here haven't tried the charring method before... sounds like it may be worth trying... I wish we could get creosote around here Nige, but the tree hugging greenies would rather you cut down more trees every 5 years instead of once every 100 years Have quite a few neighbors that use the round posts and they don't last any longer than the various posts we used... don't think I've seen .60ret. around here.but have used the .40's along with a few others and don't remember them being any different.. might have to look although they are probably up there $$$ Usually bury then label first so we can see what they were when they get yanked... at least the label survived!!! Good ole RR ties always work great I've seen fences that were put in when I was a kid that are still standing strong!!! when we demo properties a lot of times most of the ties are still usable and the owners have said they were put in anywhere from 40 - 60+ years ago!!! although around here I have been seeing the RR use some 'greener' looking ties, not sure how that will work out. The problem with living in a forestry/timber area...Hard to find anything other than what grows around here, even what they call 'white wood' for use on trimming houses around here starts rotting off in just a few years. So we'll see just what I can find... for now it's just more of the same to get the fence up.
What about steel pipe then, either concreted at the strainers or just tamped in for the intermediate posts between tee posts?
I'll have to look at price... of course if you factor in buying a $15 4x4x8' treated post every 5 years versus 1 steel post for 50 years I'll bet the steel is cheaper I know we put in a lot of 6" shd 40 steel posts for bollards and last month the price doubled to $140!!!
I would guess that you would only need about 2" or 2.5" steel or maybe even smaller so long as the hole was 4" for the strainer and thereby the diameter of the concrete bearing against the soil. Maybe get by with 1" or less for an angle brace into the dirt and weld them on site. Maybe drive the intermediate posts instead of concreting if you have a driver that would do it. Never actually tried this but seen it done and thought about it a lot.
Alot of farmers here are now using steel pipe even for strainers and the new generation post drivers vibrate them in. The stays are steel as well with a precast concrete block. None I have seen use concrete to fill the posts.One of the main benefits of using steel is that they don't burn in bush fires. Years ago I was involved in laying optic cable and they used recycled plastic markers until fires wiped them out, the crews who replaced them had a bugger of a job finding the exact spots for the replacement steel markers.
Any good creosote has been outlawed years ago now, the stuff the railroad uses for ties is still better than anything pressure treated. You can also buy used oil field pipe and use that, far cheaper than new pipe and most times much thicker walled. I"ve seen a few guys who used old railroad rails cut to length, then welded the angle brace between the corner and brace post to help give the railroad rail some more support, due to rails not having much sideways strength, but for a fence, they seem to work fine and most scrap yards will sell them second hand, some guys even go with the five finger discount method as they lay along the rail bed after being replaced, but they tend to use some skid steers or loader backhoes to lift them onto flatbeds, old rails are not something you toss over your shoulder and carry out.
All the well built fence around here uses either Osage Orange, used drill pipe, or Black Locust for posts. An Osage Orange corner post will last a century no problem. Osage and Locusts post are basically free for me, I just have to cope with all the thorns coated in inflammatory esters or something.
It's hard to beat a good Osage Orange/Hedge post as they are commonly called here in MO. We have some on our farm that are more than 100 years old and still holding wire. The more they age the harder they get, which makes driving a steeple in an old post a chore without a steeple jig. But they work well, are easy to come by and last forever. We also set posts in 3/8" gravel instead of concrete to help with drainage. We've used pipe before for line posts. 2" black iron gas pipe works great and you drive it with the tractor loader or skid steer. Just make sure the end is cut fairly square or they try to lead one way or other when you drive em. John
When I use posts I try to select them with no heart wood exposed on the sides as the preservative can not penetrate it. When I concrete posts I slope the concrete away from the post and make sure the top of the concrete is inches above the ground. If the post is center cut the heartwood will rot leaving a large wooden straw. The top can be covered with a piece of thin sheet metal or lead cut and formed over the edge some use old hub caps. Down here all we have is treated southern yellow pine. At select places CCA is still available which comes in various treatment levels. Not for ground contact, ground contact, immersion service are all different applications. Many think "treated" good for all uses.
I was taught by both the power company and my dad not to use concrete at all for wood posts. Water will run down the cracks and fill the concrete hole and rot it that way. We dig the hole and set the post and back fill with the spoils and a tamping bar, strategically dropping in larger rocks and smacking them into place to angle the post this way and that until it is plumb and the angle you want it. Then when it's solid, continue to fill with larger rocks to brace it against undisturbed ground and pack the voids with dirt going in small lifts. Sounds complicated but once you get the hang of it it is quick and efficient. The poco has hydraulic tampers of course.