Fence post mounting

The recent winds have seen the end of a boarded arris rail fence. The posts are 100mm x 100mm, 3m apart and the fence about 1.6m high with 3 arris rails per section. It was probably 30 years old. The posts rotted off at ground level about 15 years ago, and I hammered post sockets into the ground and lifted the posts with the panels attached into the sockets (which was one hell of a job - they were damn heavy). I think it did well to last another 15 years, but now both the posts and arris rails have rotted, and I think that's it.
I intend on mounting the replacement posts so they stop above the ground. One possibility is to reuse the post sockets, but the one I've uncovered so far under the undergrowth and collapsed fence is no longer vertical, so they may have had it too.
Another thought is to use concrete repair spurs set in concrete, with the posts bolted to these. There are some repaired posts in the garden like this already - they've been there 20+ years and and rock solid.
Any thoughts on concreting these in? I can't believe one bag of postcrete is enough for a 1.6m high fence on 3m spaced posts. Is postcrete a compromise over using a real cement mix? If so, what's a good volume per post, and what concrete mix?
Also, is there a different name for arris rails which instead of being flush with the post faces are mounted on the surface so the boarding is spaced slightly away from the post faces? Instead of triangle section, they are almost rectangular but the top surface is cut with a slight slope to prevent water pooling. (This is what I would like to use and have seen elsewhere, but not what the fence used before.)
TIA Andrew Gabriel
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Thursday, 14 March 2019 21:35:14 UTC, Andrew Gabriel wrote:

Andrew Gabriel, is that really you?
Over the countless years I've been on this group I don't think I recall ever seeing a question from you - you've always been the one helping others! :-)
(And, apologies, no advice from me to offer other than I've heard nothing but good things about Postcrete and that it generally is considered perfect for its job and not worth trying to improve upon, even when it is an issue of quantity)
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Thursday, March 14, 2019 at 11:36:36 PM UTC, Mathew Newton wrote:

+1 - I *always* read what Andrew Gabriel has to say on uk.d-i-y, even when I have no interest in the actual subject ;-)
Sorry Andrew, I too have nothing substantive to pass on to you. I hope you get some better replies that ours. But at least some of us heartily appreciate your presence here...
J^n
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 15/03/2019 08:15, jkn wrote:

Wow guys, thanks!
--
Andrew Gabriel

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Thursday, March 14, 2019 at 11:36:36 PM UTC, Mathew Newton wrote:

ver seeing a question from you - you've always been the one helping others! :-)

but good things about Postcrete and that it generally is considered perfec t for its job and not worth trying to improve upon, even when it is an issu e of quantity)
Installing a rabbit proof fence about 30 years ago we used pressure treate d timber for the posts but ran short for the last 3 posts where we used ata ndard round posts. Having given up on the vegetable gardening 20 years late r I decided to remove the fence posts. Every pressure treated post came ou t as new and in fact I reused them but the atandard posts had all rotted at ground level. We get these posts from a manufacturer of telegraph poles so they are the genuine pukka article. I dont believe in setting timber posts in holes back filled with cement The timber wille inevitable shrink away freom the concrete and allow water in.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Thursday, 14 March 2019 21:35:14 UTC, Andrew Gabriel wrote:

The problem is even worse now, wood preservatives are such crap these days. The fencing spikes are the best solution to rot I find. Plus give the ends of the posts a good soak in creocote/similar. In exposed situations, braces at 90deg. to the fence run are the best solution if you can fit them in. OR https://www.tekplas.co.uk/shop/pvc-fencing/outdoor-fencing/?gclid IaIQobChMI9Z7Pqc2D4QIVE53VCh169AeLEAAYAiAAEgJXh_D_BwE
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 15/03/2019 07:19, harry wrote:

I had reasonable success with delaying the rot in wooden posts by taking the concrete used secure in the ground to above the soil level. IMO the mistake most people make is to put in the postcrete/concrete and then fill the rest of the hole with soil. The post always rots at a soil/air boundary.
--
mailto : news admac myzen co uk

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

In general I don't use concrete at all if possible, it tends to keep water/dampness around the post where it enters the ground. I have a lot (probably one to two hundred) wooden posts around our smallholding and the longest lasting ones are simply banged into the soil. The quality of the posts is important, I have some original ones (which were good ones!) which are now well over 20 years old and are still sound whereas other not so good (and not so old) ones have failed.
It's quite difficult to be sure which suppliers' posts are best, ones where the supplier talks about UC4 (or HC4) treatment are probably good. Good 4"/100mm by 6' long posts now cost around £5 or more, back 20 years ago I could shop around and find them at about £1 each!
... and modern preservatives are not so bad, apparently failures reported to a wood research centre that studies this sort of thing are no more now than before the CCA (copper/arsenic) treatment was banned. Just make sure that the posts you get *are* UC4/HC4 treated, they will often be date stamped and even have a 15 year guarantee.
--
Chris Green
·

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

+1, and with flaunching around the top of the postcrete to direct rainwater away from the post.
--

Chris

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 15/03/2019 07:19, harry wrote:

I've got some raised decking sitting on those. They are rusting away. I'm not sure they'll last much longer than wood would have.
Andy
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Andrew Gabriel wrote:

I built a pergola last year, and used
<(Amazon.com product link shortened)>
I decided that the metal to be embedded was a little short, so dug the hole big enough to stand them on a couple of old bricks, embedding the whole lot in 1.5 bags of postcrete.
Being a structure, I suppose I am more concerned with the whole lot lifting/ pulling out, rather than blowing over.
I also have some timber posts for a trellis that I postcreted in about 6 years ago, and are still in good condition.
There seems to be a product data sheet and calculation tool here:
<https://tarmac-bluecircle.co.uk/product/postcrete-trade/
Chris
--
Chris J Dixon Nottingham UK
snipped-for-privacy@cdixon.me.uk
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Thu, 14 Mar 2019 21:35:11 +0000, Andrew Gabriel wrote:

It's how far into the ground the post goes that stops it falling over rather than a mass around it. Postcrete is just a quick and simple way of filling the space around the post. Rammed earth will do just as well. Best if the post is snug in the hole, so a post borer or post hole digger thingy rather than an 8" spade. Rule of thumb is 1/3 total post in the ground so 6' out of the ground, 2' in - 8' post.
--
Cheers
Dave.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 15/03/2019 11:47, Dave Liquorice wrote:

Is it just me or...
--
Robin
reply-to address is (intended to be) valid
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 15/03/2019 11:58, Robin wrote:

No.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 15/03/2019 13:11, newshound wrote:

though it (a) is a reflection of the common advice to sink 1/4 to 1/3 of the post - depending on soil, wind load etc. and (b) possibly to be welcomed as part of a cunning programme of neurological stimulation for declining Usenet users
--
Robin
reply-to address is (intended to be) valid
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Thu, 14 Mar 2019 21:35:11 +0000, Andrew Gabriel

This is what I used to repair a 7ft high fence which catches the wind as it comes around the building. The original wooden posts set in concrete had rotted and broken (albeit after 20 years)

I used Postcrete on the advice of a builder. One bag did one post. It has lasted for a few years so far and enabled me to continue to use the old fenceposts (sound above the rotten base) which I attached to the concrete posts using stainless steel rod rather than coach bolts.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Thursday, 14 March 2019 21:35:14 UTC, Andrew Gabriel wrote:

In our last house, which only had a short fence, one post lasted without ob vious damage while the rest all suffered right up to total failure. The one that lasted, I had made quite a large hole. Put fairly coarse gravel the b ottom and made it dead flat and tamped down. Stood the post on the gravel a nd then filled the sides with concrete (might have been postcrete - far too long ago to remember). That meant any water could, eventually, drain away.
In our current house, the builder has done what looks like a fine job with every post wrapped in something that looks a bit like roofing felt to about four inches above ground. Only about three years old so not really tested.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.