Concrete Post Rot Myth BUSTED - Does Concrete Rot Fence Posts?
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- čas přidán 10. 07. 2024
- When you fill in your post hole with concrete, it traps in moisture and makes the fence post rot, right? WRONG! Does concrete really rot fence posts? Today I'm busting the concrete fence post rot myth and explaining how this is false. Check it out and let me know what you think!
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I am a fence contractor in Florida, with over 2 decades of experience. We've removed hundreds if not thousands of wood fences. From first hand experience, I can tell you that it that wood posts that have no concrete versus with concrete, rot at the same rate. I can also tell you that the posts with concrete are much harder to remove from the ground then those without. I've had many more customers complain that the previous contractor did not use concrete, and as a result of a hurricane or storm, it caused the fence to lean or fall down. Because of the mostly sandy conditions in my area of Florida, I recommend concrete on wood. I can also tell you that most posts rot at the surface, where there is no concrete. Conditions are the biggest factor as to what causes posts to rot. If you have a lot of standing water in your yard, you can bet that it will rot quicker. If you don't maintain your yard i.e. clearing leaves, mulch, grass etc., it will rot quicker because of the moisture yard waste holds against the wood. If you have a particularly wet yard, and/or you don't want to be bothered by maintaining wood or having to replace it every 10-15 years. I would highly suggest a PVC/Vinyl fence instead. Yes, it is true there are some products out there that you can use to cover the wood posts to prolong wood rot, or metal posts instead, however the costs of these products usually ending up costing the same or more than a PVC/Vinyl fence. That's why I would highly recommend PVC/Vinyl instead of wood. Also, keep in mind that in 2003 the EPA banned CCA in lumber treatment,. The treatments they use today are not as good, and as a result wood fence do not last nearly as long as they used to. Fences installed prior to the ban could last 20-30 years, versus now, which is about half of that. That is likely where most of the confusion is coming from. I think most consumers are upset that wood is not lasting as long, for good reason. But the chemicals used for pressure treating lumber are the biggest factor for wood fencing rotting at a much faster pace. Just think about all products that have been produced in the past 20 years. Do they last as long as they used too? In most cases no. And in my opinion, most industries do this with purpose. So, you by their product again sooner, rather than later.
Well said. The world we live in today, one word comes to mind. PROFITS. Well GREED too.
My fence gave up the ghost after Ian, it was a warrior for 23 years. Had to replace a couple panels because of storms but, concrete is a must to counteract the influence of a heavy, rain soaked 6’ sail lol.
Florida soil(sand) is different than the rest of the country. You dig a hole in Florida and you have water. Water will rot stuff faster
Should I bring my concrete footer a few inches above the ground level in SWFL to avoid the surface rot? Does finished cedar last longer than pressure treated down here?
In regards to vinyl here in Fort Myers... I've seen so many vinyl fences blown off their posts after Ian.
@@jobney drive a few nails halfway into the post, then put a little rather dry mixed concrete in the bottom of the hole put the post in on top of that then pour in the rest. This encases the post protecting it. hen If you bring the concrete up above the level of the soil it will help prevent the post from rotting as quickly. the nails help keep the post from loosening in the concrete. If the concrete is below the soil the wood in contact with the soil will rot at the same rate as if it were direct buried. Treated is still gonna last longer than cedar. Cedar is only bug resistant and slightly weather resistant. Moisture and fungi will still damage it.
I did fencing for ten years and replaced many rotten posts. When I dig up the posts, the part surrounded in concrete is still solid. It's the part that is exposed to soil an inch or two below the surface that rots.
Right. That's because rot is a fungus that needs oxygen to survive and the deeper you go underground there's no oxygen.
I am actually surprised by how long wood can last (untreated) even in soil. My garage was very poorly built in the 1960s, and a lot of the studs were somehow under soil, semi rotten, but I cut the rotten parts off, and literally 1cm above soil level, the studs were completely solid good lumber. wtf. I think I am just going to glue and nail 2x4s to the bottoms and pour concrete and have another few decades added to this crappy garage lol
@Boogie Man you have to bring the concrete slightly above the soil tapered away from the post so no water gathers and it will prevent the rot. It rots were the soil touches the post. If your not going to do that you might as well just do a footing and call it a day. It’ll rot one way or another.
@@speakyourmindnow3548I’ll never understand why fence guys can’t seem to understand this. Concrete isn’t a solid material. IT’s absorbs moisture. It will release the moisture into the post. You have to put a vapor barrier of some form down to prevent this and it’s just not functional with fencing. You would have to
Put a trash bag in every hole before you set the post and
Poured the concrete. Pour a concrete pad and watch to sweat. Moisture is going to draw through it to come out and it just keeps absorbing and releasing more. Sooner fence guys actually learn this the better off they will be.
Cuz that's where there is oxygen for the fungus to grow that eat the wood.
My experience. I built a 40' long bridge over the creek behind my house 20 years ago. I water jetted the posts into the creek bed and did not put any concrete around the posts. The bridge is still there and posts are all firm. That same year I installed 400 feet of cypress fencing closer to the house with and put concrete around half of the posts. Several of the fence posts have already failed and in each case the ones that failed had concrete around them. In each case, the post was rotted off just above the concrete and just below the concrete. I live in South Florida and the ground is wet the entire year. Personally, I will not be putting concrete around any future fence post installations, as they seem to last longer without it. I also have to question the quality of the pressure treated lumber these days compared to the pressure treated lumber 20-30-40 years ago.
A youtube account called Peter Ward has many videos showing professional restoration of centuries old timber framed houses in England. It gets a bit much actually how often he is cursing and picking away at concrete which seems to cause the wood to rot everywhere it touches. Only lime mortar is safe to use on these old houses. The footage of concrete rotting wood there is plentiful and convincing. Concrete seems to provide a surface for anerobic microbes to harbour and spring into life every time temperature lowers and the surface hydrates. It seems to cause wood to rot over time simply by being in contact with it. Peter wards videos even show it rotting old stonework.
then the concrete was trapping moisture around the edges of the concrete rims.
One of the most interesting topics…. Love to hear the differentiating opinions. Truth be to about what I know in that most posts “break or rot” right at or above grade. In the many hours of research I’ve done I have found the best method it to set the post in concrete and use a trowel to make the concrete slope away from the post, and then don’t back fill it with dirt! Even though this won’t entirely prevent the rot from occurring it will definitely slow the process. Also, one thing to note is that WOOD WILL MOVE. Even if you set it in concrete, the post is more than likely wet when you place it and therefore when the post begins to contract (due to moisture loss) then a small gap develops between the post and the concrete which will also invite water to hang out next to the post. I do think that it is funny how many fence guys use gravel in the bottom of the hole… to help the water drain out of the bottom of the post…. Thai is a very funny concept to me as in the area I live we have lots of clay and rain. There is no way any amount of gravel would keep the post dry.
Also, I recently dig up a few posts that weren’t rotten at all, but the previous fence contractor set the concrete about 10” below grade and tree roots had actually grown through the post and broken it off. Thus another reason that the concrete should go all the way to the top of the soil or grass line.
you got this right, I've had to dig up too many posts and concrete due to rotted posts at the surface, those completely surrounded by concrete were still intact those with gravel were gone at the bottom and rotten on the way up
I dont know if I buy this one. Concrete is porous and also has moisture of its own. I've also removed many posts sealed with conrecete that had rotted bases and perfectly fine tops.
You beat me to it.
Does the post sit in water when it rains or is the concrete mixed right? I have found capping wood post with a cement dome helps keep the puddled water away from the post
EVERYTHING is porous, but, concrete does contain water because water is a lighter molecule than the concrete pores unless the pour wasn't done correctly, which is why I always tamper my pour to get out air bubbles. you ever see a nuclear reactor? their made of concrete. then you'll get those who have had to seal up the basement walls (there's actually a special paint for that) this is due to sweating or a bad pour
Reading around the issue it seems it's less about how the post is installed, and more about where the post is installed. The type of soil... water table... etc... I live in a heavy clay and the bottom of the posts are thus rarely exposed to water because the clay doesn't let the water permeate in the same way as a loam soil allows it to filter down. In addition, while I'm at the bottom of a slope allowing runoff and underground water flow, I'm on a raised section where there's a two foot drop into the next garden so the water has a place to run. All that considered, a fence post of mine rotted out at the surface level, so going forward the low permeability of the soil and next door neighbour not having a gutter on their shed where the post rotted indicates I'm more likely to have a surface issues on posts, rather than rotting in the ground problems.
A well mixed and poured concrete should not be porous. Any moisture that may come to the post later could be from the soil underneath.
There are a ton of theories, many that make some sense to me, but what is missing is a good ASME publication on the subject of wood post setting in soil best practices. It would cover different soil conditions (clay, sand, frost, dry & wet). Thoughts: Is the concrete used hydraulic (not porous to water), or porous? Is the soil wet 300 days a year or dry? My gut tells me that if the soil is basically dry 300 days a year, having a mini French drain at the bottom and around the edge of the porous concrete would be best, or even using only 3/4 crush base rock to allow it to dry right after any rain etc. In all cases the burred post up to 6" above grade needs to have treatment (0.40 lb/cf or better) or it will rot and get eaten. In my area, we have heavy clay with some loam, and get about 40 days of rain per year, mostly in three months. I think it would be good to have the post be basically dry 85% of the time, and the ASME guys are the one to guide us on how to achieve that.
It's when rain water or watering the area around the fence, when the ground is above the concrete that water travels down the post into the hole. The post is being kept moist from the retention caused by the dirt. The same concept of why you mulch around trees. Just took out three post set in concrete. The one that had concrete above the ground came out in one piece. The two others below ground level were rotted and broke off and what was in the concrete was completely soggy.
That is my experience too. There is no need to set a wooden post in concrete. Water will almost immediatly get trapped between the wood and the concrete and the post will never dry. It will rot after a few years. I've seen this time and time again after 37 years in the construction business.
I removed some posts that had been set in concreted holes for forty years. Still solid. When I set posts in concrete I trowel the concrete to stick above the ground and slope away from the post toward the outer edge.
I appreciate you sharing your experience and process!
I recently saw an advertisement for a post wrap that actually glued to the post at the ground line. They have a 20 year warranty if you use their product and they showed how the product works and it seem to have some merit. Have you heard of any of this?
I’ve pulled out many wood posts. I’m my experience, the rot is always near the surface. Never in the concrete.
Agreed 👍 🤝. Did this on deck 4 x 4 posts. And still working
Joe, I am in Minneapolis and frost line is about 48 inches. The best I can get with my auger and cleaning out by manual auger is 44 inches.
So pour concrete then pull it up a little too let it seal. What concrete do you suggest? My father in law says high strength stuff that takes a long time to cure. Im just not sure if that or the quikrete that you add water to in the fence hole is best.
TLDR what's better.. 80lb bag of high strength concrete or more expensive "fence post" concrete you add water to after it's in the hole.
Ever notice a tree stump covered in soil wil rot but when it's not covered it will not rot so when it's covered it has right conditions for microbes. So I believe concrete pier with anchor bracket is the way to go along with side load bracing ?The only way it can rot is if water penetrats wood
Thank you for the no BS Q&A. I'm beginning my life as a do-it-yourselfer and have a lot of questions. Hehe.
You’re very welcome, thanks for watching!
0:40 Will the post still _"act like a candle"_ if the top portion of the post is stained and sealed (such as the Expert Stain and Seal) with regular reapplication maintenance?
I am looking at building a fence, and am looking at the "char and tar" method for the part going in the ground, with a nice mahogany stain and sealant on the post. I'm curious if I'm destroying any breathability in the wood with that method, though, and thus promoting rot/decay.
Would it be a bad idea to add dry concrete mix to the bottom, add the post and then surround it in concrete. Essentially encapsulating the post from the ground down in concrete?
Down south they use a concrete meant for this. You don't even add water it pulls moisture from the ground you just pour in the bag and setup post. Northerners make fun of these "hillbillies" but I've met some old timers that are far from stupid and their work has held up longer than I've been alive
Okay, first off when you set the post in concrete you just make it harder to replace. 2nd, you don't want water to wick into the wood, that's what causes rot in the first place. Build your fence like you would build a roof. You want to keep water away and give it an escape path. If the post has a really heavy load to carry key it. There are times when concrete is helpful but like everything it's a tradeoff. Best to avoid it if you can.
Will post rot below 18 to 22 in of concrete ? Gravel footage, post with 12" dirt, then 18" to 22" concrete to above surface? Will there be rot and at what point?
Good info but ... What he did not take in consideration is that the wood shrinks at least a quarter inch that space allows water in and creates a "bathtub" for the post. The gravel below will allow the water to drain out of the bottom. Installing signs in the ground for 30 years I learned this.
You are exactly right.
Even if the post shrinks, if it's encased on concrete, there's no way for the water to get in, except in theory at the very top above ground. So you should make sure to add a layer of concrete around the post above ground, sloping away from the post. Then you should keep any gap that opens there sealed (with polyurethane silicone for example) to prevent any water getting in.
I agree somewhat, but the wood shrinks and separates from concrete which it leaves a gap between concrete and the post which fills with water. To add concrete to the top sloping and filling with silicone is a good idea, but 2 problems. 1. no fence builders are doing this. 2. When I install post for the best look you want to leave 2-3 inch of the top of the concrete to be covered with dirt or sod so the concrete is not seen. A wooden post that has the least amount of moisture will shrink as it dries out and leave a gap between post and concrete, Metal will not do this.@@JoeQuinn-Sott-net
Any thought on bags being used, I've seen a couple of videos where guys use plastic bags as a vapor barrier? Also, should you pour a small base first and let it set so the under bottom isn't sitting on dirt? Sorry if these questions sound dumb, I'll be putting my first fence up sometime come next spring.
it is a good idea to paint with regular paint bottom of the post which will be in a concrete ?
Concrete/cement has been used in wooden boat bilges for over a century with no issues. In reality, the wood surrounding the concrete is generally in better shape than the rest of the boat as a result. Likely because of the highly alkaline nature of cement.
That is because the bilge is coated with lead paint and asphalt.
im with you on everything except the claim that concrete keeps moisture out. concrete absolutely does not keep moisture out and can very easily hold moisture itself. the only aspect in which concrete is better than just dirt is the capacity at which it can gain and hold moisture. so concrete is beneficial as far as reducing the amount of moisture but it is wrong to say it seals out the moisture.
...agree, in fact that actually demonstrates the whole concept.
If concrete would totally block out water then there was no way that water could be sucked up the post and evaporate because there would be nothing to replace that water drained at the bottom, inside the "concrete cup"
Im putting up a new wood post fence on my farm , ive treated the lower wood post with asphalt sealer , post are set in concrete, can i paint the above ground post with the same sealer creating a solid black post...thanks
Great info, Joe! The Fence Expert knows his stuff!
What if you place the sono tube section 4 inches above grade and pour to this height.
Seems to make sense to me since the post always rir at ground level 😊
Thank you!
Awesome explanation!
Thanks for watching and weighing in!
I understand your explanation but I disagree, Concrete holds moisture and in contact with wood will provide a steady source of moisture to the post. (I have never seen a post dry that has been encased in concrete) I have found the best treatment has been to soak pressure treated posts in oil (at least 4 to 6 inches above the soil line) and pack the posts with aggregate so the water can drain and get away from the post itself. I also see you can buy some commercially available post sleeves made with tar that have the same effect. Another tip that is good is to bevel the tops of your posts or cap them to keep moisture from sitting on the top. I "paint" the top of my posts with oil to seal them.
@Boogie Man You can use almost any oil most guys use used motor oil as it is free, but I have also used used hydraulic fluid as well. Packed with gravel I mean a little in the bottom and then all around the post (fill the hole with gravel) It allows water drainage and moisture to get away from the post itself.
You are correct.
Question....if the moisture is going to wick upwards and be evaporated out with or without concrete...why do I need to secure the base with concrete? I have seen other methods of securing the post without concrete...is there more benefit to using concrete rather than other methods?
YES THE POST IS STIFFER, GOOD FOR HIGH WINDS, ETC ETC, WHY WOULD YOU JUST COMPACT THE SOIL, THAT'S NOT ENOUGH, SOIL LOOSENS UP WITH MOISTURE
Put all my privacy fence posts four foot deep and no gravel under the pours, 20 years and still solid. Neighbor after my install didn't ask and just tamped around his with only soil. Second attempt he used gravel. The next owners replaced it with you guessed it concrete.
Where's the actual demonstration of this in action??? I am only taking your word for it at this point?? Not saying your right or wrong just where's the actual proof to backup your statement?? I have pulled up posts encased in concrete and the the concrete has been still thoroughly soaked in ground moisture as well so it seems as though the concrete would still act as a wick itself in most cases.
The problem is that the wood will shrink as it dries creating a gap between the post and the concrete. This is where the water enters and eventually breaks down the wood, right at the very top of the concrete. I had fence posts set in concrete at ground level (no soil touching the fencepost" fail after about 10 years. The posts rotted out just below the concrete. Then again, I live in the very wet PNW so I probably have more constant wet than most. My posts set in paver base stay strong year after year so the water can drain out. Our soil is glacial till, with clay, some sand, and a lot of rocks. It packs hard under dry conditions. Sandy soil likely doesn't pack enough for the paver base method.
Thank you
Will the concrete post heave on winter?
I've been wrestling with this subject the last few days. Mentally exhausting. I got some old telephone poles that I'm gonna use and what's interesting is that one has a metal tag that says Ozark Fence Co. Then I see that's you! The man himself. So anyhoo, I'm going with concrete, if I don't read anymore opposing views. :) The plan: Dry concrete at bottom. Maybe some water then mix a little. Set post with 3 long screws in the lower sides. Then repeat with the concrete. Slope concrete above soil. Roof tar applied a foot below and about 6 inches above on the post. Maybe even apply on top of the concrete slope. Going in a 3 foot hole wider at the bottom and I may carve a few notches at the bottom because of my OCD. I don't plan to ever remove, and if I need a new post I'll just move right next to it and do it again. I'm convinced at the moment that the post can be wet all the time and not rot underground, so I'm not gonna worry about treating the underground part any further. They are telephone posts so they have been treated already. My pond has an old dock and the posts cannot be moved. I am convinced that the trouble spot is just above ground so hopefully the tar will prolong it.
That’s awesome! The telephone pole had a ln Ozark Fence sign on it?
So what would be the fix if my deck post are rotten and already surrounded by concrete. Does the whole concret slab need to be removed? Or can post just be replaced and put on above ground concrete footings ontop of already exhisting concrete slab?
Could probably just mount the deck to the concrete at this point
It's accurate. I've seen the rot. When wood touches concrete it transfers moisture, but it takes years. I know a house right mow where they poured the slab after they had framed the house and the concrete is touching the studs and they're all rotting at the bottom. Now this house was built in 74 so it took a while, but now it's got to be fixed.
1:31 this myth doesn't hold water. Well played!
Right on man, 100 % agree from my personal experiences
I appreciate you sharing your experience!
Water seeps through concrete it doesn't matter what you do that post is still going to get wet
Yep, was gonna say. Not easy to make concrete that water wont move into if submerged.
I ALWAYS THOUGHT THAT BY ADDING GRAVEL AT THE BOTTOM WAS A FOOLISH IDEA, I RATHER STOMP THE SOIL DOWN COMPACT WITH THE POST ITSELF AND LAY IT FLAT ON THAT COMPACTED SOIL, MAKES MORE SENSE TO ME, GLAD WE AGREE VIDEO GUY
My experience (everyone is different- diff materials, geography, soils, weather, installs) is that rotting is generally where moisture and air can combine to support rot bacteria and fungus. That's generally at ground level or at top of concrete if soil is porus enough to allow oxygen to combine with H2O.
sounds like the soil just needs good drainage around and under the poles most of all with or without concrete. Also maybe also poke holes around the soil around the posts often to allow ground to get air and breathe.
I use prune and seal on bottom of post before I install it
I totally agree with this guy. Basic physics and makes sense.
What do you think of rotbloc type products?
I’m thinking wouldn’t putting the post in a sleeve actually not allow the post to be imbedded in concrete? Like the post could be pulled up through the sleeve if said sleeve wasn’t stapled to the post. Other than maybe protecting the post at and near ground level from rain not draining away or snow sitting a few days or more,, this just doesn’t seem right to me.
I’m not familiar with that product. I am familiar with PostSaver, which is heated to bond the sleeve with the post.
You ever heard of putting long screws in the sides toward the bottom of the post before being set in concrete so it creates an anchor of sorts?
you can also stapple a rattle chain or log chain around the lower part of a post to anchor it in the ground better or bolt or weld a disk blade to the the bottom of the post, extra anchoring is sometimes needed for heavier gates that might otherwise push down your first brace post or pull up your second brace post the gate is hung on
It’s not the concept that you’re trapping in the moisture, you’re trapping in black mold. Yes concrete causes the pole to rot faster much faster.
Great point, I hadn’t even considered mold!
definitely a great point ive never considered.
So do you have a video on how to Ezy way replace a cemented post if it fails?
A concreted post is easy to pull out of the ground (if you have a front end loader). They're a lot easier to pull than a driven post. All you have to do is move them side to side just a bit and they come out like a rotten tooth. However if the top of the post is gone good luck. Happy digging.
Why don't you have a plastic sleeve covering the post up to above ground a foot or so as I have heard of on pole barns? Then your post will be dry from day one. And how do you really see what's going on under ground?
I have rotted clothes line post holes in the ground where 10ish inch posts were.
Posts dipped in plastic. However they do that.
0:39 In a dry environment, this makes sense. What if the post is getting a substantial amount of water from above the ground? Is it going to be dry on top and wick moisture up and out? I doubt it.
What do you think to metaposts we call them in the Uk a spike with a Square top to fit the wooden post made of metal.
They are OK for smaller fences but any weight and the metal spikes shift in the ground. I use anchor shoes large steel ones, however even those don't hold the Post like a 3ft hole filled with concrete - nothing dies. Except come 15 years I won't repkabe the post as it drys out as not in contact with porous arterial - cobreye or soil. If I have replace post I will unlock it and usvrew attachments lift out a d respite new one.
This not only makes sense... I have a slab in my basement where somebody over 40 years ago (probably much longer) left the wood 2x4 edge form in place, and poured another concrete slab up against the same from on the other side, so it cannot be removed. The wood is exposed on the top, and is as dry as a bone with no signs of rot or concrete cracking at all after 40+ years.
I appreciate you sharing your experience!
Well your wood isn't in contact with moist soil...
I have a question. If wood doesn't rot inside the concrete, (if done right), then why does almost everyone stop the concreate a couple of inches below level of topsoil? Since that topsoil is what is rotting all the posts. If they just poured concrete to the level of the soil, problem solved.
here in Texas depending on the treatment concrete aound a post - fence will fall down in a few years
Good man. Sounds like the answer I wanted. Assume painting the bottom of the post in bitumen paint is a bad idea when setting in concrete? But top/cut ends in bitumen is ok?
No it is a good idea as is surrounding the post with gravel.
I'm not using concrete for my 4x4 pressure treated fence post. I'm using Sika foam. Should I still use gravel? And, great job explaining your videos!
Theoretically hes right but the fact that concrete soaks up moisture from the ground cause the post to soak it up too and rot where it meets air. Use a footer and connect it with steel it wont rot
So the question then becomes, how do you encapsulate the bottom of the post with concrete?
@@JoeEverest makes sense!
@@JoeEverest would it work to just pour some of the dry concrete mix in the hole first and set the post on that?
Also do you dig the extra 6" or do you dig 2 feet and the pull the 6" back?
Toss a cheap red brick in for the post to set on, then pour. Lowe’s and HD sell em.
Do I need to FILL the post hole all the way to the top or can I top the set Quikrete with pea gravel
@@JoeEverest no this is bad advice. water will just go into the pea gravel and keep the post wet, then a few years latter grass clipping and stuff turn into dirt and now you have 6" of dirt in contact with the post.
I dip the base of the post in roofing tar after painting the bottom of the post in copper Marine rot resistant treatment
That seems costly
@@Couchlover47 I just had to replace a 6x6 post. It was cast in concrete and rotted form the top down. I'm not sure your method helps much though. The other gate post was the same age and is perfectly fine without any significant evidence of rot and it was set the same.
One more thing is....water in the concrete is used by the hydration process (a chemical reaction) of cement which creates the binding strength between aggregates and develops the strength of the concrete itself. So, that water is not just sitting there rather being used up by the concrete. That's why we don't pour concrete on the dry surface cause dry surface will steal water away from the concrete affecting its strength developing process.
In my opinion wood that stays wet rots no matter how you install it in the ground. If the post is stuck in the shade and never get a chance to dry out it will rot way faster than one that gets sun everyday.
We use wood in a lot of marine applications. Some temporary, other to last half a century. Wood completely wet and submerged under water may last centuries in fresh or salt water. When you look at piers, old docks, salt ponds, industrial supports, or marsh structures, the area above the water are strong decades later. The areas below the water are strong decades later. The areas we find fail to rot are the areas where the wet meets the dry. That border area that constantly gets wet and then drys over and over again. We regularly build fences through wet areas for security purposes at power plants, wildlife refuges, oyster farms, military bases, swim areas, and tourist resorts.
@@rfarevalo sounds like placing sea salt around wood posts might be helpful after reading that.
Try putting a shovel full of asphalt milling in bottom of hole tamp down for compaction set ur post an back fill with asphalt milling an compact. No waiting, instant compaction nice bug barrier
The only way I do this now is just installed a metal pipe With a vital post around it.
You have to vibrate the pipe all the way down
To last longer,which is better,pressure treated wood or ceder ?
I would love to know where this "expert" gained his expertise! A little background on me: I spent nearly 10 years building mostly above ground power lines. The only poles we set in concrete were steel and 99% of the time they were set on concrete not in it. The concrete was simply a stability footing that the poles were bolted to. I do recall removing galvanized steel poles that were set in concrete and the part of the pole below the concrete line was very degrated/rusted to the point of crumbling in some circumstances! In the case of wood poles there are basically 2 types used in power: disgusting creosote and what we called green which is simply pressure treated as familiar in lumber. Creosote is a far superior protector simply because water does not penetrant petroleum although it is very difficult for the creosote to penetrate to the core or heart of the pole which is easily seen pulling an old pole where the entire center is rotted out both at top and below ground. The creosote is very very good at protecting the outer most layers of the pole. I have personally pulled poles that were still partially in a usable state and had been in ground for nearly 100 years. Green poles are uncommon in the utility industry, however I suspect the same wood (lol) be true because they both use a pressure treating process and the cores do not get wetted nearly as well although the green treatment does permeate much easier. Lastly but most important which our expert failed to even touch on is the environment the poles will be set in; ie: soil quality,density and moisture content; cold,icy, anual snow and permafrost vs dry and arid(desert). Dependant upon the environmental factors expansion and contraction will exist, vary widely and are the biggest reason I have personally seen for rot below grade in concrete settings. Concrete does not contract at the same rate as wood therefore there will eventually be a gap around the pole/post below grade which will hold water and water permeates wood better than concrete! In summation you should know the conditions the pole will need to survive and can put safeguards in place to help mitigate premature degradation. Some utility companies adopted placing caps on the tops of poles to prevent the majority of the rain from eroding and rotting them. I read one comment here where someone mentioned coatining the bottom of the pole with a substance with high resistance to moisture and it was probably the best one I saw. There is another issue with this and that is dryrot however the bottom of the pole/post should not be coated which will help prevent this being a problem. Good luck friends
@@JoeEverest
Thanks buddy! It's nice to have a vlogger respond. Btw I saw a few more of your videos and they're great! We used the same a/b foam substance to set poles in that you test in your other vids. It is awesome stuff. Oh and as far as depth there is an old rule that still holds true in the utility industry: 10% of length +2'; ie a 50' pole gets set 7' on average. The dirt is tamped around the poles very tightly also. A step missing from many fence posts.
Great info. Thank you. But how does "dry rot" is prevented when bottom of the post is not coated? Post will soak the water and wick it up. "Dry rot" is just a misleading name for that fungus. It actually must have moisture to survive and eat the wood. May you explain please?
Wood expands and contracts and when temperatures change it can create gaps where the concrete was poured. If water gets into the cracks it will seep into the post cavity and rot the wood. I have built miles of fence and only use concrete on steel posts. This also varies on where you live. A place that have a lot of moisture won’t really make a difference. If you put a wooden post 4 feet in the ground there is no reason to use concrete. Save your money.
Part the gets me as a professional fence builder does not mention the soil conditions and why. Florida is not Oregon. Texas is not Washington. Clay Soil holds water
I got a privacy fence that's at least 10 years old. Some of the posts are rotting, but others are perfectly fine. How'd this happen? Neglect. Years of rotting leaves created a small 'hill' of soil which covered the posts, making them rot at the base. I dug some of them out, only one I could pull up straight from the ground because of how soggy the dirt was. So that's another thing to take into consideration.
I've thought of this idea recently... what about putting the posts inside garbage bags when placing them into the ground and then pour in the cement around the outside of the bags? If there are any crevices or cracks in the cement, the garbage bags would certainly keep out any outside moisture.
or hold all the moister once water gets in from the top or through some hole.
I know this is your business but you didn't present any data at all. Although I liked what you were saying, I just heard theory. What makes this method any better than the other methods? thanks,
... from my experience, anything made of wood that is in contact with cement that is exposed to the elements or any source of moisture is toast. As has been pointed out earlier, concrete holds moisture because of it's porosity. I've taken apart enough of my own work over the years to see it first hand. It may also depend a lot on where you live, your rainfall amounts. just my $.02...
@@user-vd4bk1ll9m just put a rock in the bottom and put the post on top that you don't need to put concrete at the bottom
I wrap all post with water and ice roofing material.
From the numerous studies done on this topic I was under the impression that rot is a living fungus that needs oxygen to survive. After about 6 inches of soil going down from grade level the post can't rot because the rot doesn't have the oxygen needed to live hence if there's rot happening it's happening 6 inches down from grade and up.
@Boogie Man the problem is that so many people are assuming the point of the concrete is to protect the post when its not. the point of the concrete is to provide a solid foundation.
davidclark6694 - Is there any evidence that some sort of tar product protects the post?
So if I fence in my 40 acres with treated fence post I'm supposed to set all of them in concrete? The ones I put around my 7 acres in florida I just stuck in the dirt 25 yrs ago. Their still good. I'm scratching me head on this one. 😷
Depends on the soil and type of fence. Sandy soil can pack, but the clay we have here it will move all over. If it’s a 4’ fence and your posts are set 3’ deep around a pasture can maybe get away without, but concrete keeps it straight and solid.
What about painting the post with marine anti-foul bottom paint?
Hmm, I don’t have any direct experience but it seems to make sense!
Has anyone tried placing lime or salt instead of concrete? Since it is porous but at the same time alkaline for fungi. In ancient times lime was used a lot, concrete did not exist.
Interesting, I’ll have to research this!
Concrete is expensive to make (environmentally), to buy, install, and makes it very difficult to uninstall/repair a post and disposing of. Much easier to just not use it. If you want to pre-coat a post with something,, not sure what, but that probably would be a reasonable solution. Perhaps just dip the base in concrete or lime.
Every time it rains a puddle forms around the base of my post.
I would create a diagnol slope with some kwikrete or something all around the 4x4 where it meets the ground. Then put paintable caulking in the crack where water enteres. Be sure you have copper green in all parts that will be underground / caution: If it gets in ur eye will cause irreverseable eye damage. Then have small rocks at the bottom of the hole you dig.
Just removed a 25 year old deck some 800 sq ft all the 4 x 4 were in concrete all were a bitch to get out like pulling an anchor out of the ground all intact no rot. The bottom of the posts were in the concrete and poured short of ground level .
Wat if you wrap the bottom of the post with roofing paper
water goes around roofing paper, anyways it's the 2" above the post and 6" below the ground that typically rots and causes failure, not the very bottom.
My fence installer put my posts in with concrete but when it dried, there are now a motes around the posts that collect water. I want to mound up more concrete so the water will shed away from the posts but I don't know how to get the new concrete (or cement if I can use hydraulic cement) to stick to the old concrete. Any ideas on how to do this would be appreciated. Thanks for all the great videos!
use concrete bonding adhesive...sold everywhere. For extra credit, wrap your post in butyl tape at top to hold concrete off a bit and allow a good seal. Can add a bead of exterior caulk also, but best if something more flexible than concrete closes the last 1/4 inch
😉 it's not the concrete that rotts the post the part that rotts is the part above the concrete where it's exposed to air same as normal corrosion water and air b3st idea is when you concrete pack the concrete into a mound so the water can run away better if you leave a bowl where a puddle can form then your post will last half it's life expectancy 😎 C and S FENCING. FENCING Scotland for 20 years 😎
This debate is actually quite ridiculous. There are far, far too many variables affecting one side or another to ever arrive at a definitive answer. Wood rot is caused by fungus. Putting concrete around it or not is for all intents and purposes irrelevant. 1. The chemicals present in pressure treating wood are intended to prevent the fungus from attacking the wood, but not all pressure treating is equal. Take any cross section of pressure treated wood and examine the penetration of the chemicals. It is not uniform nor deep and as soon as something penetrates that layer … well, guess what? 2. Concrete is very caustic … the fungus won’t like it, but neither will the wood. 3. Temperature is another variable …. warm is better for fungal growth. 4. The type and prevalence of the fungi in the soil is important. 5. The availability of oxygen for the fungi is important as well. Continuously submerged wood may well cut off the oxygen supply to the fungi except where water meets air and that is where it will rot. The fungi like damp not submerged. The concrete will not eliminate an oxygen supply to the wood. 6. The list goes on …
The bottom line is that there is no simple solution to wood rot and one situation cannot be extrapolated to another. You haven’t busted anything at all, I wish you had, but such is not the case. Personally I choose to use just 3/4 minus gravel in my post holes simply because it easier to remove the damned things when they rot, not because it prevents the rot. Properly compacted by tamping it will survive as well as concrete, but the tamping is a lot of work with a heavy bar.
I appreciate the insight!
I also find alot of rotted posts because contractors concave their concrete towards post, instead of forming concrete to shed water away from post. I also find alot where concrete is slightly below grade which causes post to hold water.
As an MBA of fluid mechanics, your theory of wicking holds no water and is completely wrong.
They now sell vinyl coated 4x4 posts... Might be a good idea
@@JoeEverest yeah, hold off your enthusiasm... $42 each at Homies Depot.
Too pricey. Make your own sleeves or make your own oil wash for your posts or char them.
What if my fence gets wet during winter and freezes? could it break my fence? Thanks for the vids
Thanks for the responsa Just kind curious
💯% it’s the moisture trapped around the TOP of the concrete that causes post rot, usually if the concrete is dipped toward the post the water can’t run off, if you slant the concrete gently away from the post or even better, use a bitumen sleeve and also slant the post, the chances or post rot are greatly reduced.
Interesting theory. But you have any proof to back up this theory?
Nothing besides 24 years of experience? I’d certainly love to see some sort of study with peer reviewed proof, if available!
this only stands true if the concrete mix is done correctly. If done incorrectly, concrete itself is porous, and it not mixed correctly, can dramatically increase water penetration.
I'm fairly certain that no mater how concrete is mixed, it's porous or you wouldn't need to put a vapor barrier on a concrete slab before installing laminante flooring
@@TwoTall1988 of course, but concrete that is mixed correctly can withstand/slow down water penetration signifcantly.
@@TwoTall1988 Typically concrete is quite hydrophilic.
Did you check back on your fence posts in 20 or so years?
no prof just jibber jabber I am 65 I set posts when I was 14 they are still there we just took the time to tamp the soil from bottom to top, I have seen lots of post fall over that where set with concert
Agreed. Everybody is too lazy to set a post the way it needs to be set. It takes a little more time (plus a little know how) to set a wood post . Best method I have found is a little creek gravel and the dirt that came out of the hole. And tamp it in a bit at a time.
@@roykey3422 so you pack dirt around the wooden post? I realize it works because I do the same with base rock, but if my life depended on it, I would surround post in concrete with bitumen tape around post.
Joe, Conctete draws the moisture out of the post making it dry then rotting it’s called dry rot but if it’s a fence it’s common practice
No. Water is caught between the concrete and the wood. Wood being porous wicks that moisture even if it is pressure treated. The wood once it starts to dry out then shrinks make the condition even worse. Pressure treated lumber was never meant to be a constant state of wet.
What if you tar the whole post?
Not the very bottom. You’ll create a cup
@@badarticle9132 very bottom doesn't rot out. it's the 2" above and below grade that rots.