Help with fencing (not the type using swords!)

[Student]

I need to replace an existing lightweight fence with something more robust. I’m OK with the woodwork side of this but I’ll need fence posts every 2 metres which involves groundworks. Many sources, including fencing suppliers, suggest digging a hole 30 inches deep, putting gravel in the bottom for drainage; putting in the fence post, levelling it in the two vertical dimensions, fitting braces to stop it moving and then using postcrete to fix it in place.

However, there are others who point to the problems of doing this as the post can rot at and below ground level. Their recommended solution is, I believe, to build concrete bases and then use post holders such as these to fix the post

https://www.toolstation.com/bolt-down-post-shoe/p72512

or, if not bolt down, these

https://www.screwfix.com/p/sabrefix-con ... pack/70197

However, if I go down the route of a bolt down support, I’m unsure as to how I get the concrete absolutely level in 2 dimensions since, if I don’t, a 3 mm discrepancy at the base could be 40 mm at the top of a 2 metre post. In the case of concrete in supports, although I can get the post level in 2 dimensions before pouring the concrete, I’m unsure as to how I get the base of the support to be at exactly ground level.

The solution is probably perfectly obvious but not to me.

 

[Trevanion]

I'm no expert on the subject but I've bored out softwood posts before that have been in the ground for 20+ years that were concreted in place with no rot whatsoever, I've also been told the postcrete is pants and accelerates rot to within a couple of years and you should use a proper mix if you want it to last.

I imagine it's all hearsay anyway, everyone will have a different opinion on it.

 

[Billy_wizz]

I wouldn't use bolt downs! What type of fence are you doing?

 

[Blackswanwood]

Hi - is using concrete posts an option?

If not I would put a piece of ply with a vertical piece of timber attached to mimic the fence post and use it to check the surface of the concrete was level when trowelling it flat after filling the hole.

 

[Homers double]

Why not set concrete posts instead of wooden ones?, there’s not a massive price difference between concrete and wood posts, but it’s will save you any further issues with the posts, if your doing close board fencing you could set Concrete spur Posts and then bolt wooden posts.
I used the slotted posts myself and built a frame within the slots then Fitted close Board slats on to the frame, it all got painted in Bedec barn paint which cost a bit more but it lasts way way longer than any fence treatment.

 

[Richard_C]

I replaced posts and panels on the short side of my garden last year and I'm about to embark on the 17 panel long side. It's been there 30 years. It was installed with concrete spurs, I think they call them Godfathers in some part of the country. It makes replacement a breeze, remove or in some cases grind off old rusted bolts, bolt new wooden posts on, no groundwork needed, leave them a bit slack until you get the panels in place, tighten it all up, job done.

It really is a good investment if you expect to live in the same place for a long time. To my mind they look better than full height concrete posts, and are lighter to handle, because mostly they are hidden behind plants in the border.

In contrast on another side it was wooden posts cemented in with all kinds of rubbish including chunks of hard flint and soft chalk. Posts rotten at base, again after almost 30 years. The effort to dig out the old cement was immense even after buying a cheap sds hammer. I hated that job.

So for future proofing, concrete spurs or posts seem to be the best answer.

 

[rafezetter]

What's the budget and how long do you intend to stay at the property?

If it's a long time then you might want to consider the concrete repair post (spur) option and then bolt the wooden post to that. It's a halfway house between full concrete posts and wooden ones, but the bottom of the main wood posts can be elevated a bit off the ground, enough to allow them to dry out, thus extending the lifespan.

For getting them vertical in the postcrete (which is fine for this application) prebolt the wood post to the concrete one about 100mm below the bottom hole (and do them all the same), drop the concrete post into the ground and use 2 or 3 long bits of wood, roofing battens are good for this and screw to wood post at right angles to level it up vertically with a spirit level while someone else holds it.

Personally I would make the hole deeper than required so that the concrete post IS NOT touching the bottom of the hole when the wooden post is resting on something like 2 pallet slats atop each other that span across the hole. This way you can get all the posts to the same level (assuming the ground is levelish), and you're not faffing trying to dig the hole to an exact depth to ensure the tops of the fence posts align, which visually is pretty critical.

This would give you a fence system that is much sturdier than just a wooden one, without the issues of rot and should last a long time indeed.

Another bit of experience I would pass on is don't cheap out on the featheredge boards, spend a bit more and get something thicker - thin cheap carp ones with knots everywhere will twist and warp and cup and do allsorts in the first hot weather, gaps will open up between the boards and it'll look truly awful, as our fence done by previous owners will attest, it's been an eyesore that the landlords won't pay to replace even though the gaps between the baords are 20mm in places and at the right angle it might as well not even be there.

 

[AndyT]

I'd say the simplest option is the metal spike that clamps onto the post, this sort of thing

https://www.screwfix.com/p/sabrefix-fen ... pack/50094

I've used these (not this brand but similar) and they have lasted 20 years or so already. Admittedly, they are holding up posts which only hold light trellis, so they might not be suitable for a tall solid fence on a windy hilltop.

Quick and easy to install. No concreting needed. The timber post can finish an inch or so above the soil level. Minimum disruption to existing plants.

 

[heimlaga]

In my oppinion there are three sane ways of doing this.

!. The old way. Digging a hole. Placing either some gravel or a flat stone in the bottom. Putting the post in place. Filling with stones of the size you can lift around the post placing them so that they fill out the hole and lock the post in place the best possible way.
What you get is a replaceable post. You can dig out the stones and replace the post at any time.

2. Pouring a concrete base and using a metal bracket of some sort to which you can bolt the post once the concrete is set. What you get is a post that will last until your children have died from high age and then be easy to replace at any time.

3. Using a metal spike that cramps onto the post and is driven into the ground.
What you get is a cheap and easy substitute which is fully adequate for a low fence not subjected to heavy loads.

Setting a wooden post in concrete only makes an awful lot of work for someone to do in the future. The post will rot and once rotten it will be very difficult to replace without a good sized JCB.

If I was to use the bracket method my brackets could be a lenght of hot rolled U-channel. Set in the concrete and held upright by a few braces while the concrete cures. Way easier to align than those short ones sold.
Or maybe a bracket held by bolts to the leveled surface of the already cured concrete. You can drill the bolt holes in appropriate positions after the concrete is cured so you need to get only one plane right when pouring.

 

[LarryS.]

To align the posts my method is to get the two ends posts in and put string lines between them. Depending on where you put the lines you can give yourself a very easy set of guides to height, vertical, and front face plane


Sent from my iPhone using Tapatalk Pro

 

[Rorschach]

The post will rot at the place where air and water meet, in a buried post this is at ground level and at the top. It's a just a given for a wooden post no matter what you do and the best you can hope for is to slow it down.

How long do you want it to last?

 

[Suffolkboy]

I'm no expert on the subject but I've bored out softwood posts before that have been in the ground for 20+ years that were concreted in place with no rot whatsoever, I've also been told the postcrete is pants and accelerates rot to within a couple of years and you should use a proper mix if you want it to last.

I imagine it's all hearsay anyway, everyone will have a different opinion on it.

20+ years ago they used to treat fence posts with preservative that actually worked.

When I started as a student I was told the lifespan of well erected stock fencing was 50 years.

You are lucky to get 5 years out of the ***** we get today.

 

[HappyHacker]

I do not have the answer but can tell you one of the things that do not work well:

Wooden posts in concrete. Gravel etc at the bottom of the hole makes no difference in my experience, the post will, as Rorschach said, rot at ground level, even if you continue the concrete above ground level and slope it away from the post, this may give it another couple of years. A 9 inch square post may last up to 20 years, smaller posts less. This is based on putting fencing up for my garden and fields for horses and regularly replacing it for over 40 years.

The stick in the ground/bolt on tin post holders, five to ten years if not galvanised, they are not good for anything other than light fences.

Concrete posts last but don't look good especially when not properly concreted in and they start moving. Tree roots also push them around over the years.

A neighbour, a farmer, fed up with replacing wooden gate posts now puts steel RSJs in on the basis that by the time they rust he will be long gone.

The advice to use good wood rather than thin feather boards is good, the little extra cost will be repaid in less maintenance and better appearance over the years.

I had a 6ft high hit and miss fence professionally erect about 15 years ago. I have noticed a few of the posts are no longer doing much and I will be trying to fix then this summer. It will not be an easy job given their position. I may stick another post or two either side just far enough away to miss the concrete of the original post.

I have not tried the other suggestions but there must be better alternatives to wood stuck in the ground.

 

[Rorschach]

I have not tried the other suggestions but there must be better alternatives to wood stuck in the ground.

There is, a wall! :lol:

Seriously though the absolute best solution is a breeze block wall set onto a foundation. It will last forever with zero maintenance. But it is ugly. You can render and paint it but that means maintenance in the future.
If you like the wooden look you can clad the wall to make it look a bit more like a fence. The wood should last a decent length of time since it isn't in ground contact and not subject to much wind etc. Easy to replace later on as well as it is only an aesthetic change rather than structural.

 

[Geoff_S]

Have you thought about composite fence posts? They just do not rot.

 

[Student]

My thanks to all who have responded and for all your positive comments. Your responses have made me realise that I should have been more specific about what I am hoping to do.

First of all, the fence in question is only about 10 feet long between the end of next door’s garage and a tree lined hedge. The ground slopes down quite sharply and there will be a difference of some 18 inches over the 10 feet. I want to put up a picket fence 6 feet tall so will need three posts although one may be able to be bolted to the side of the garage leaving two to be fixed in the ground. I installed a picket fence in my front garden a couple of months ago but, in that case, was fortunate that there were concrete posts already in situ to which I could bolt the fence posts.

The existing fence being replaced consists of three 6 foot high by 3 foot wide square trellis panels supported by 50 mm square posts held up by drive-in post supports but, as mentioned in my OP, this is too lightweight and I want something stronger.

In answer to Rafe’s questions, we’ve lived in our house for over 40 years and, at our ages, may not be here for more than another 10 or so although I would like the fence to be around longer than that. Budget isn’t a problem for the length involved. Taking into account the various views expressed, I think that I’ll go along with Rafe and Richard C’s suggestions of using concrete spurs.

Thanks again for all the positive and helpful comments.

 

[marcros]

is a hedge an option?

 

[Garno]

Not trying to be funny or anything here I genuinely do not know the answer to this.

What if (or is it possible) you encase the part of the post going into the ground with polythene or plastic or maybe the stuff used for damp proofing. As I say I do not know what would happen to the wood if done this way.

 

[Billy_wizz]

The obvious answer as someone who fixes fencing is to fit one post to the wall and one at the end of the run )wood with a concrete support post pre attached to side of the post) 4x2 rails then fix lose pales dropping a small amount with each one assuming the drop is fairly uniform! Would that be something that would work for you?

 

[Tris]

Not trying to be funny or anything here I genuinely do not know the answer to this.

What if (or is it possible) you encase the part of the post going into the ground with polythene or plastic or maybe the stuff used for damp proofing. As I say I do not know what would happen to the wood if done this way.

Ag merchants now sell heat shrink tubing for exactly that purpose, basically cos the tanalith stuff is carp since they took the arsenic out.