Just a quick few thoughts while sorting the fencing at the start of the shed build. Nothing too scientific but hopefully worth showing what to avoid where possible. Of course, as well as concrete and composite posts there are endless sleeve type products and preservatives to protect the timber further. 👍
I'm a fencer and tree surgeon by trade, I've done an awful lot of fencing over the years and wanted to point out.... nothing really, great video, spot on advice! It may be worth mentioning that the length of post in the ground should be a minimum of 1/3rd the length out of the ground, so an 8ft post will suffice for a 6ft high fence... BUT, there are many caveats to that, if it's soft ground, go deeper, if it's hard, well compacted rocky ground... well you'll be probably be fine to skimp on a couple of inches if needs be, obviously the fence run's angle towards the prevailing wind should play a part in determining how deep it needs to be, as well as how exposed to that wind it is as well. Although it certainly happens on occasion, it's very rare to see a post that has failed due to not being put far enough in the ground, it's almost always as a result of rot at ground level. A mistake I see far too often is people using absurd amounts of concrete to set their posts in (the worst I've seen is a row of 3x3 posts set 3ft in the ground, surrounded by 2ft of super hard concrete on each side... to hold up a 4ft high larchlap panel fence!) and / or using a ridiculous mix (like 2 to 1), it's pointless... and makes the job of extracting the post a nightmare! Postmix is ideal when it's feasible to use it. Oh one last tip (not applicable to the post you showed when considering it's purpose): If using an auger to do the holes, and the ground is a bit loose or soft, then square up the hole a little with a graft, it increases the surface area in contact with the ground and will help resist movement, you can also "bell" the bottom of the hole out a little, this means more of the ground will need to be lifted before the post will move, and saves on concrete or postmix.
Great video with some excellent thoughts, and good additional points from "Sinule". An observation I made from my time putting up stock fencing for farmers in the UK (where we just thumped the post into the soil) is, as you noted the post almost always fails due to "rotting" around the "neck", where the post emerges from ground level. When we first started fencing we used untreated posts, but after a few years some of these would start rotting through and breaking at the neck, so to improve the longevity of the fencing we then began using treated timber posts instead. However, we found this made no particularly discernable improvement to the working life of the post, they were still rotting away around the neck and braking. So over a period of time we went back and looked at some of our old fencing jobs with both the treated and untreated posts, we also dug a few of the broken posts up and a few unbroken ones as well to compare them. And we always found the end of the post in the ground was damp/wet but had not rotted, and the end of the post that was out of the ground was generally dry and not rotted, but the neck was always the problem, why did it always rot here even when treated? Eventually we found the answer one day when talking to a boat builder who explained what the issue is. What happens at the neck is the wood goes through a cycle of wetting and drying which causes the wood to continually swell and shrink which in turn causes the structure of the wood to brake down and gives the appearance of having "rotted" away. Which explained why treating the timber made no discernable improvement to the posts working life. As someone said in another reply, the only real way to improve the longevity of the wooden post would be to use a "better" species of tree for the post (typically oak, here in the uk) or to keep the post out of contact with the ground, using one of the many ways mentioned in the video and the comments. Hmm, a long winded comment, but just trying to give some context to my understanding of the problem.
Bitumen paint the post part going into the hole or you can theses heat on post sleeves, put a layer of gravel on bottom of post hole and post mix to ground level troweling round the post to make drain away. Check out Charlie Diyte video
I’d agree with you apart from the gravel. It sounds good in theory but the postmix will completely encapsulate all around the gravel meaning its drainage potential is completely lost
Concrete spur/repair posts for fencing. You bolt your wooden fence post to the spur that way it's not in contact with the ground. Post rots or breaks unbolt it and replace. Costs more to begin with but it should last a very long time 😀😀 Love the videos they have motivated me to crack with my DIY projects.
I just can't see the point in using concrete with fence posts. It doesn't really reduce rot, it doesn't make the post that much more stable (proven by the fact that you pulled yours out the ground so easily), it is faaaaaaaaar more time consuming to do than just pushing a bare fence post in, if you have put enough concrete in to hold it still more than just being a bare post in the ground a bit further then you haven't got a hope in hell of removing it without a tractor / digger, and finally when you do end up needing to replace it (which you will at some point) you now have a load of concrete to get rid off whereas before you could just burn the ex-fence posts. I do a lot of fencing (and particularly strong stuff as well because it's got to keep horses in and if they want to they can snap most wood like match sticks) and I have always found that concrete is far more effort than it's worth! The only time it's been worth it is for 10' / 12' gates with steel galvanised posts which won't rot/rust. The issue with wood in concrete is that wood expands and contracts a lot compared to the concrete, so you will always have a crack down between the post and the concrete. This allows air in (which is the real reason wood rots near the surface, not the water per se). SO, this is why posts in clay last a hell of a lot longer than normal or sandy soil which last a hell of a lot longer than concrete because the air can't get as easily down next to the post (just think of Venice, built entirely on untreated over a 1000 year old posts which are completely sodden in water and haven't rotted / degraded at all because the air can't get to them). I've pulled over 100 year old untreated gate posts out of the ground and thought they were in such good nick that I repurposed them. We've got bare fence posts in the ground that are chopped up (to about 6' by 3 - 4") creosoted telegraph poles and they've been in for almost 40 years, and were in the ground as telegraph poles for probably another 50 years before that! Moral of the story, concrete is waaaaay more effort, for no more (or even less) gain! Just stick them in bare with some creosote or good preservative on it.
another option to increase longevity is timber species. Generally pressure treated products rely on the chemicals to prevent decay but species such as larch are very durable in ground contact and will outlast pt products every time. Then there's sweet chestnut which will last for even longer, robinia even longer.
teatimetraveller I saw some ‘tropical hardwood’ sleepers on eBay. Reclaimed but not more than 0.5 cm rot. Might not be the most economical or eco friendly though!
@@alun101 well if they're reclaimed then its a good solution. Jara is the one to look out for. From Australia, they used to make sleepers out of them and the most durable timber in the world.
Im building a 6ft concrete post fence. Im using 8ft posts. Sounds great saying yeah we'll go down 3ft, but you try digging down 3ft through clay! 2ft and the posts feel very solid. Im going with the prevailing wind here anyway so there isnt massive amounts of horizontal shear.
@@alun101 true, but of the holes I dug half hit concrete /bricks which needed the sds to get through. If I'd hit that with a post hole digger it would be a bit bent 😂
I cut out the old 2 1/2" pipes from the orignal oil heating system out of the cellar, welded on brackets then concrete in. Have since replaced the fence panel after a 11 years post are still as good and made putting new fence panel in a day job.
Austin Anderson The concrete is very viscous. Would it run under the post? I put it in before the post. Then it settles at the bottom. Top rot is the real issue though, as the videos says.
Also, out company doesn't like to use tar and chemical treatments. So for us this is probably the best and most environmentally friendly option to avoid soil contamination
Stick any part of the post that will be below ground level into a fire to burn the wood for a 1/16" - they will give you 30-40 years service. This is how farm fences were/are built. No chemicals, no cost, no messing. A bit of gravel at the bottom so the base can drain is good too.
If you staple a strip of plastic around the post at ground level it will last years longer. One thing to mention if you stand any building structure on a concrete pad it’s then classed as a footing. You can lay a flat concrete block down to support but you have to be careful with footings. Footings are building structures and may need permission. This is why people sit things on blocks and spreader plates. You can build huge sheds as long as the sits on the ground not in it.
Might be different in the UK as all planning for outbuildings is based on height, footprint and distance from boundary. The structure itself is not really a deciding factor, unless I’m wheels I guess.
The Restoration Couple I am a house builder in the uk. You can put a garden building in up to 4 meters high as long as it’s 1m from a boundary line. Planning officers if called by neighbours will look at what the structure is built on to determine whether it’s okay to stay. Even a concrete slab as a shed base can be taken as a raft foundation. There has to be a deciding factor as to whether something is a build that needs planning permission or a garden structure and footings is it. Just a bit of info for you.
Height rules change at 2m from boundary usually otherwise the new workshop design would have benefited. 😔 Still never heard that a freestanding structure is exempt, shipping container maybe, but even a shed with a regular timber base/floor sat on gravel still classifies as an outbuilding in the world of planning/permitted development. I’d love to be wrong though! 👍
FYI. I put in fence posts that have been tanerised in new fashion with post knocker into regular wet ground and they have lasted only 5 years and rotted at the ground level. A local chap has ordered some new posts from Sweden that use old chemical preservatives. J
If your not going to put concrete and drainage around them they are just going to rot no matter how they are treated. They are wood! Did you watch the video?
Hey Tim, a quick question if you have time please.... Your pizza oven countertop, do you leave the ply under the concrete? If so, do you attach or leave that to the weight? Thanks abs keep up the great vids!
Allot of the life of the post depends on the treatment of the wood and the locality. Where I am (Texas) a wood post is often seen as a 10 year fence not because of rot but because that post is a filet minion to termites. And no they don't care about the treating chemicals. I have seen termites decimate railroad ties. My preferred method for a fence where I am is to use drill pipe. Drill pipe is cheaper than the cheap tubing posts often used however it is extremely heavy. It is anywhere from 4mm wall thickness up to 8mm depending on the usage. It lasts forever and they can be reused by hitting the pipe and the concrete will break off. The pipe is cheap because scrap metal places won't buy it due to it having a small amount of NORM (radiation) from the act of drilling into the ground. It is well under the acceptable limit but scrap metal places don't want to deal with it out of the lack of information about it. For light duty stuff that I see as temporary I will use a wood post.
@@alun101 It's just like it sounds. It's the drill pipe that is used for drilling gas wells or used for swabbing gas wells(cleaning the bore). Since well drilling is very common here there is allot of used drill pipe available. It usually runs about $1 a foot (delivered) and is available in 2 3/8 which happens to be standard fence post diameter. Sizes up to 4.5" as well. Very very heavy pipe in 31' lengths. They can't melt the pipe as scrap metal because of the small amount of radiation from drilling into the ground but it can be used for fence posts, posts for metal buildings etc. Just very heavy to work with. The 2 3/8 for fence posts weighs 6.65 pounds per foot AKA 3 kilo per foot so a regular 8' fence post would weigh 53 pounds ( 24 kg). I have about 250+ feet of fence to do at 8' tall so that means even heavier posts at over 10' long but they last forever.
Any thoughts on posts for raised decking (500mm or so)? I have an existing patio and I'm thinking of putting the posts straight onto the flags where I can but there is going to be a section that is over the garden and I was going to do something similar to what you have done for your shed and build a square base where I can bolt down a shoe.
I think booting would be fine but bitumen paint the parts that won’t be exposed to the air. Add fresh wood preserver to the other bits. You don’t know how long it’s been since it was pressure treated.
or use a bit of bitumen paint around ground level. or as i did, burn the lower portion "shou sugi ban" style . then bitumen on top of that, will last a lifetime then :)
It’s all myths. Painting doesn’t do much more than the chemical used to treat the post. Plus the concrete surrounds the bottom of the post so it never sees water. These post sleeves you hear of are shite, just a gimmick, the concretes the sleeve. Using halves of bricks in the post hole to plum the post creates voids for water ingress also, just get your concrete in and tamp it down, simple. The main part to rot is where the concrete finishes at the surface. Try to keep it sloped but if on grass it’s not easy(grass put back at ground level with soil). Just get plenty paint on or clear treatment every year. Fence posts can last a good 20+ years easy. Sloped tops help also. The worst part of fencing is the digging. Hi ho hi ho it’s off to work we go.......
Just a quick few thoughts while sorting the fencing at the start of the shed build. Nothing too scientific but hopefully worth showing what to avoid where possible. Of course, as well as concrete and composite posts there are endless sleeve type products and preservatives to protect the timber further. 👍
I'm a fencer and tree surgeon by trade, I've done an awful lot of fencing over the years and wanted to point out.... nothing really, great video, spot on advice! It may be worth mentioning that the length of post in the ground should be a minimum of 1/3rd the length out of the ground, so an 8ft post will suffice for a 6ft high fence... BUT, there are many caveats to that, if it's soft ground, go deeper, if it's hard, well compacted rocky ground... well you'll be probably be fine to skimp on a couple of inches if needs be, obviously the fence run's angle towards the prevailing wind should play a part in determining how deep it needs to be, as well as how exposed to that wind it is as well.
Although it certainly happens on occasion, it's very rare to see a post that has failed due to not being put far enough in the ground, it's almost always as a result of rot at ground level. A mistake I see far too often is people using absurd amounts of concrete to set their posts in (the worst I've seen is a row of 3x3 posts set 3ft in the ground, surrounded by 2ft of super hard concrete on each side... to hold up a 4ft high larchlap panel fence!) and / or using a ridiculous mix (like 2 to 1), it's pointless... and makes the job of extracting the post a nightmare! Postmix is ideal when it's feasible to use it.
Oh one last tip (not applicable to the post you showed when considering it's purpose): If using an auger to do the holes, and the ground is a bit loose or soft, then square up the hole a little with a graft, it increases the surface area in contact with the ground and will help resist movement, you can also "bell" the bottom of the hole out a little, this means more of the ground will need to be lifted before the post will move, and saves on concrete or postmix.
Great video with some excellent thoughts, and good additional points from "Sinule". An observation I made from my time putting up stock fencing for farmers in the UK (where we just thumped the post into the soil) is, as you noted the post almost always fails due to "rotting" around the "neck", where the post emerges from ground level. When we first started fencing we used untreated posts, but after a few years some of these would start rotting through and breaking at the neck, so to improve the longevity of the fencing we then began using treated timber posts instead. However, we found this made no particularly discernable improvement to the working life of the post, they were still rotting away around the neck and braking.
So over a period of time we went back and looked at some of our old fencing jobs with both the treated and untreated posts, we also dug a few of the broken posts up and a few unbroken ones as well to compare them. And we always found the end of the post in the ground was damp/wet but had not rotted, and the end of the post that was out of the ground was generally dry and not rotted, but the neck was always the problem, why did it always rot here even when treated? Eventually we found the answer one day when talking to a boat builder who explained what the issue is.
What happens at the neck is the wood goes through a cycle of wetting and drying which causes the wood to continually swell and shrink which in turn causes the structure of the wood to brake down and gives the appearance of having "rotted" away. Which explained why treating the timber made no discernable improvement to the posts working life.
As someone said in another reply, the only real way to improve the longevity of the wooden post would be to use a "better" species of tree for the post (typically oak, here in the uk) or to keep the post out of contact with the ground, using one of the many ways mentioned in the video and the comments.
Hmm, a long winded comment, but just trying to give some context to my understanding of the problem.
Bitumen paint the post part going into the hole or you can theses heat on post sleeves, put a layer of gravel on bottom of post hole and post mix to ground level troweling round the post to make drain away. Check out Charlie Diyte video
The post saver sleeves are way to go - used widely by fencing contractors
I’d agree with you apart from the gravel. It sounds good in theory but the postmix will completely encapsulate all around the gravel meaning its drainage potential is completely lost
Concrete spur/repair posts for fencing. You bolt your wooden fence post to the spur that way it's not in contact with the ground. Post rots or breaks unbolt it and replace. Costs more to begin with but it should last a very long time 😀😀 Love the videos they have motivated me to crack with my DIY projects.
That's what he was saying should only be used on the corners, as they are not strong enough for straight bits (in his opinion).
The tar flame on post savers are worth it big time
I just can't see the point in using concrete with fence posts. It doesn't really reduce rot, it doesn't make the post that much more stable (proven by the fact that you pulled yours out the ground so easily), it is faaaaaaaaar more time consuming to do than just pushing a bare fence post in, if you have put enough concrete in to hold it still more than just being a bare post in the ground a bit further then you haven't got a hope in hell of removing it without a tractor / digger, and finally when you do end up needing to replace it (which you will at some point) you now have a load of concrete to get rid off whereas before you could just burn the ex-fence posts.
I do a lot of fencing (and particularly strong stuff as well because it's got to keep horses in and if they want to they can snap most wood like match sticks) and I have always found that concrete is far more effort than it's worth! The only time it's been worth it is for 10' / 12' gates with steel galvanised posts which won't rot/rust.
The issue with wood in concrete is that wood expands and contracts a lot compared to the concrete, so you will always have a crack down between the post and the concrete. This allows air in (which is the real reason wood rots near the surface, not the water per se). SO, this is why posts in clay last a hell of a lot longer than normal or sandy soil which last a hell of a lot longer than concrete because the air can't get as easily down next to the post (just think of Venice, built entirely on untreated over a 1000 year old posts which are completely sodden in water and haven't rotted / degraded at all because the air can't get to them).
I've pulled over 100 year old untreated gate posts out of the ground and thought they were in such good nick that I repurposed them. We've got bare fence posts in the ground that are chopped up (to about 6' by 3 - 4") creosoted telegraph poles and they've been in for almost 40 years, and were in the ground as telegraph poles for probably another 50 years before that!
Moral of the story, concrete is waaaaay more effort, for no more (or even less) gain! Just stick them in bare with some creosote or good preservative on it.
Good ‘start-of-learning-curve’ stuff here!
another option to increase longevity is timber species. Generally pressure treated products rely on the chemicals to prevent decay but species such as larch are very durable in ground contact and will outlast pt products every time. Then there's sweet chestnut which will last for even longer, robinia even longer.
teatimetraveller I saw some ‘tropical hardwood’ sleepers on eBay. Reclaimed but not more than 0.5 cm rot. Might not be the most economical or eco friendly though!
@@alun101 well if they're reclaimed then its a good solution. Jara is the one to look out for. From Australia, they used to make sleepers out of them and the most durable timber in the world.
May I be the first to say, nice video! I usually run a piece of DPM around the post that goes a few inches in to the concrete and a couple above.
Good idea. The sticky bitumen sleeves do a similar job and I guess would reduced risk of water getting trapped between dpc and wood.
Im building a 6ft concrete post fence. Im using 8ft posts. Sounds great saying yeah we'll go down 3ft, but you try digging down 3ft through clay! 2ft and the posts feel very solid. Im going with the prevailing wind here anyway so there isnt massive amounts of horizontal shear.
Steve spark You could try a post hole digger. They’ll go down and down through clay.
@@alun101 true, but of the holes I dug half hit concrete /bricks which needed the sds to get through. If I'd hit that with a post hole digger it would be a bit bent 😂
I bought 6ft close boarded fencing as a kit, the posts are 8ft. I think a rule of 1/3rd of the above ground length makes sense.
I cut out the old 2 1/2" pipes from the orignal oil heating system out of the cellar, welded on brackets then concrete in. Have since replaced the fence panel after a 11 years post are still as good and made putting new fence panel in a day job.
Solid! Good thinking. Might be over kill for a chicken run though. 😃
I give the posts a tug upward after the concrete has been poured so some is able to slip underneath the post.
Smart
I wonder whether this might unintentionally create a sort of cup/basin in which water would become trapped?
Austin Anderson The concrete is very viscous. Would it run under the post? I put it in before the post. Then it settles at the bottom. Top rot is the real issue though, as the videos says.
Good straight forward information. Regards AJ
Yeah great video...
To be honest all your videos are brilliant 👍
Yeah, I use galvt 'H' ankers a lot. Bit more work, maybe? But no direct contact with the soil and easy to adjust
Also, out company doesn't like to use tar and chemical treatments. So for us this is probably the best and most environmentally friendly option to avoid soil contamination
Good information!
also look at burning (charring the surface) for rot protection.
Stick any part of the post that will be below ground level into a fire to burn the wood for a 1/16" - they will give you 30-40 years service. This is how farm fences were/are built. No chemicals, no cost, no messing. A bit of gravel at the bottom so the base can drain is good too.
If you staple a strip of plastic around the post at ground level it will last years longer. One thing to mention if you stand any building structure on a concrete pad it’s then classed as a footing. You can lay a flat concrete block down to support but you have to be careful with footings. Footings are building structures and may need permission. This is why people sit things on blocks and spreader plates. You can build huge sheds as long as the sits on the ground not in it.
Might be different in the UK as all planning for outbuildings is based on height, footprint and distance from boundary. The structure itself is not really a deciding factor, unless I’m wheels I guess.
The Restoration Couple I am a house builder in the uk. You can put a garden building in up to 4 meters high as long as it’s 1m from a boundary line. Planning officers if called by neighbours will look at what the structure is built on to determine whether it’s okay to stay. Even a concrete slab as a shed base can be taken as a raft foundation. There has to be a deciding factor as to whether something is a build that needs planning permission or a garden structure and footings is it. Just a bit of info for you.
Height rules change at 2m from boundary usually otherwise the new workshop design would have benefited. 😔 Still never heard that a freestanding structure is exempt, shipping container maybe, but even a shed with a regular timber base/floor sat on gravel still classifies as an outbuilding in the world of planning/permitted development. I’d love to be wrong though! 👍
Some good tips 👍
FYI. I put in fence posts that have been tanerised in new fashion with post knocker into regular wet ground and they have lasted only 5 years and rotted at the ground level. A local chap has ordered some new posts from Sweden that use old chemical preservatives. J
You can still get hold of the original creosote
If your not going to put concrete and drainage around them they are just going to rot no matter how they are treated. They are wood! Did you watch the video?
Hey Tim, a quick question if you have time please....
Your pizza oven countertop, do you leave the ply under the concrete? If so, do you attach or leave that to the weight?
Thanks abs keep up the great vids!
Allot of the life of the post depends on the treatment of the wood and the locality. Where I am (Texas) a wood post is often seen as a 10 year fence not because of rot but because that post is a filet minion to termites. And no they don't care about the treating chemicals. I have seen termites decimate railroad ties.
My preferred method for a fence where I am is to use drill pipe. Drill pipe is cheaper than the cheap tubing posts often used however it is extremely heavy. It is anywhere from 4mm wall thickness up to 8mm depending on the usage. It lasts forever and they can be reused by hitting the pipe and the concrete will break off.
The pipe is cheap because scrap metal places won't buy it due to it having a small amount of NORM (radiation) from the act of drilling into the ground. It is well under the acceptable limit but scrap metal places don't want to deal with it out of the lack of information about it.
For light duty stuff that I see as temporary I will use a wood post.
Robert Adams Not sure we have drill pipe in the U.K. can you describe what it is?
@@alun101 It's just like it sounds. It's the drill pipe that is used for drilling gas wells or used for swabbing gas wells(cleaning the bore). Since well drilling is very common here there is allot of used drill pipe available. It usually runs about $1 a foot (delivered) and is available in 2 3/8 which happens to be standard fence post diameter. Sizes up to 4.5" as well. Very very heavy pipe in 31' lengths.
They can't melt the pipe as scrap metal because of the small amount of radiation from drilling into the ground but it can be used for fence posts, posts for metal buildings etc. Just very heavy to work with.
The 2 3/8 for fence posts weighs 6.65 pounds per foot AKA 3 kilo per foot so a regular 8' fence post would weigh 53 pounds ( 24 kg). I have about 250+ feet of fence to do at 8' tall so that means even heavier posts at over 10' long but they last forever.
What if it’s set in just concrete as in no soil near it at all?
Any thoughts on posts for raised decking (500mm or so)? I have an existing patio and I'm thinking of putting the posts straight onto the flags where I can but there is going to be a section that is over the garden and I was going to do something similar to what you have done for your shed and build a square base where I can bolt down a shoe.
I think booting would be fine but bitumen paint the parts that won’t be exposed to the air. Add fresh wood preserver to the other bits. You don’t know how long it’s been since it was pressure treated.
Motor oil / diesel mix and bitumen on the ends... will probably outlive me
Yip spot on👌
I've done exactly this to my back garden fence.
Here's hoping it works😬
Well, that's not environmentally friendly is it!
Not environmentally friendly!
@@googleuser4239 Is it not, why is that then?
Lot better than tipping it away or sending it to landfill...
The chickens were laughing!
I have dug out and put in way over 1000 fence posts why am I watching this.. Why do I watch half the stuff on youtube??
:)
Care to share some tips from your experience?
Yeap, dig a hole first 😂
@@zjzozn do I use a spade or a jigsaw to make the hole?
@@jacobhall979 Get someone else to dig the hole with the spade.
You can do the jigsaw while they dig
Be careful not to lose any pieces though
@@imeach2897 I lost all my pieces
Would have been interesting to knock the concrete off the post to look at the condition of the wood.
M&M In my experience it will be as good as new.
I recommend www.postsaver-shop.co.uk as the bitumen sleeve protects the area prone to rotting. Not cheap but worth the money.
or use a bit of bitumen paint around ground level. or as i did, burn the lower portion "shou sugi ban" style . then bitumen on top of that, will last a lifetime then :)
Chris C Nice. Never thought of burning and bitumen.
The ‘golden rule’ is 1/4 in the ground. Ie. 1.8m above ground, 600mm in ground.
That's a 1/3?
It’s all myths. Painting doesn’t do much more than the chemical used to treat the post. Plus the concrete surrounds the bottom of the post so it never sees water. These post sleeves you hear of are shite, just a gimmick, the concretes the sleeve. Using halves of bricks in the post hole to plum the post creates voids for water ingress also, just get your concrete in and tamp it down, simple. The main part to rot is where the concrete finishes at the surface. Try to keep it sloped but if on grass it’s not easy(grass put back at ground level with soil). Just get plenty paint on or clear treatment every year. Fence posts can last a good 20+ years easy. Sloped tops help also. The worst part of fencing is the digging. Hi ho hi ho it’s off to work we go.......