We've just had some new fencing installed, featherboard with capping rails on
4" posts. All from Jacksons Fencing, pressure treated and 25 yr guarantee. The posts have slightly sloping tops, presumably to encourage runoff. Should I put caps on these posts to protect against rain? I'd need flat-top plastic with sides so I could cut one side off and slide it up to the fence. Trouble is all those I've seen have pointy tops which would look a bit silly, sloping.
I don't usually bother with fence posts - the bases rot through at or just below ground level fast enough that capping them is largely irrelevant to their lifetime. I'm in wet windy North Yorkshire. YMMV
I do cap (with lead sheet) larger wooden gate posts which makes them last a lot longer. Otherwise sooner or later the top splits and leaves and junk accumulate until something grows in the resulting hollow.
I put in a new fence around 2001. I cut the posts at at angle at the top. Ignoring a couple of posts damaged by a car, the only one I’ve needed to replace rotted at ground level about 4 years ago. Even that one got ‘nudged’ by another vehicle or it would probably have lasted longer.
You should probably be OK. I habve some pressure treated stuff and (some of ) it failed after about 10 years below ground level, but the tops were all fine.
Did they come like that, or has the installer cut them? If the latter, it might be worth getting some end-grain sealer to stop water wicking into the grain. If they came like that I'd hope they are pre-treated.
I'm assuming wood for the posts. I have had fences built this way both concreted in and otherwise, always within ten years they are rotting near ground level since I don't think they make the preservative good enough now. I've also had them warp and twist, not got if its a gate post. Tops, well assuming wood, how would you hold them on and stop water getting in and sitting on the end of the post. I think I'd be tempted to put something like an extra coat of preservative on the ends and just down the sides as the bit at the bottom will go first if its got poor preservative. Brian
PS, I went for Concrete posts last time. You can replace panels far easier, particularly if they are the slide in sort. Brian
A common misconception if the panels have been in many years, and tree branches have grown across them. In that case, the panels cannot be lifted up far enough to clear the concrete post grooves. the only way is to cut away the tree branch, and Murphy's Law will arrange for a TPO to be position for that tree.
From my experience I would say yes with a sloping end being the next best thing. I have always capped timber posts and never had any rot just the occasional need to replace the odd cap.
I recently repaired some of my fencing following last Spring’s gales. Although we have concrete posts with one foot concrete base panels and 5’ feather board panels, one section dividing me from my neighbour has timber posts and one post showed severe rot from above. I have no idea how long the fence had been up since it was erected by the previous owner but it was notable that it was not capped and left flat.
As for sliding in panels between concrete posts all I can say it is easier said then done. Wany lap fencing which is quite light and flexible yes. Rigid heavy framed feather board is another matter even for two people with appropriate ladders or platform. During my repair session I did replace two of the feather board panels and found it easier to construct the panels in situ, but I am fortunate to have a decking and fencing yard round the corner from me and was able to get all the separate components mostly ready cut so no end treatment required probably worked out dearer than buying a complete panel but a simple one man job.
Since the effective anti-rot chemicals were banned long ago, even pressur treated wood will only survive for about 7 years when in contact with soil.
Local county councils used up a big chunk of S106 money in 2013 to create a series of steps on a footpath that had a significant slope. They used 6x2 pressure treated flooring joists cut to 1 metre lengths and secured with 2x2 battens hammered into the ground, then the soil levelled out between each 'tread'.
8 years on at least half the 6x2's have rotted away to nothing and had to be replaced.
Early rot, is a sign that "Above ground" PTL has been used improperly where it is not suited.
And when a post at least, is treated, the end grain in the post, picks up a lot of chemicals. You do not really want to be cutting the "good stuff" off the end of a post, if you expect to gain an advantage from the ends. Buy an eight foot post, and make a deeper hole, rather than cut the post and ruin it. Putting a cap on it, will prevent water from pooling on it.
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For some of the cheaper caps, the cap materials will fail, before the post does. I've seen plastic caps with a crack in them for example.
Well I'm just saying, the end of the post sucks up a lot of chemicals (because of the grain exposure).
What you do with a post, is up to you. If you buy a post at a building supply, it has square cuts on the end. And as delivered to the building supply, the PTL is "wet". No attempt is made to dry PTL after it's been treated. And it will dry in the lumber yard, as it sits in the sun.
The wetness of PTL makes a big difference to the weight of the item when you load it on your vehicle. I just about got a hermia, lifting a 6x6 PTL, because I had picked a "fresh" "wet" one off a new pallet of them.
The next one I picked up, was from a pallet of ones that had dried in the sun. And the one I took off there, felt like it weighed half as much as a wet one.
I think the highway department experimented with the "slanty" cut for guard rail posts (versus the previous flat cut that used to rot from the pooled water on top). The result ? They gave up on wood entirely, and now make the posts out of metal. Problem solved :-)
When they put power poles in a swamp here, they used hollow fiberglass poles. The poles were two sections, you fit the lower section to the swamp first (and make a pier out of rock around it). And then the upper section slides over the lower section. I didn't see it get installed, and that's just from looking at the finished work. I figured something should happen to a thing like that, but it's held up well, and no signs of failures of any sort. I know of only one stretch of road, using poles like that.
And the concrete poles, the ones made by loading up a hollow form and rotating it at speed until the concrete sets. I consider those to be a failure, because the rebar in them rusts. The pole can fall over, before maintenance people discover the rotted ones and replace them. Usually with wooden structures, there is a relatively long interval of "ill health" to give away that the pole needs maintenance.
Virtually all fence posts fail at the ground level where they are subjected to a continual cycle of being wet and dry. This is exacerbated by water penetrating via the end grain below the surface. With all my fence posts, I thoroughly seal the end below ground with thick bitumen and continue the bitumen coating up the post until 5" above ground level. Then I put roofing felt over the bitumen whilst it is still "wet". Guaranteed to last for decades and decades. At the top end, I apply a coat of gutter sealant. Never fails!
I'm minded to obtain some PVC sheet 1mm thick and cut to 4" squares to match the tops of the posts. Then get some of this:
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I can make three edging pieces to protect three sides of the top of the post, then cap it with the PVC square mentioned above. The whole to be fixed down with silicone. The fourth edge of the post is butted up against something, can't remember what just now.
I already used the 40mm version of the corner edging to protect our cat flap entrance which goes through a brick wall. Sealing that with silicone worked very well.
There is also the problem where after treatment the wood dries out and cracks allowing water to get behind the treated layer. I've seen this a lot of the top of posts where the cracks are in the end grain.
Friends installed 8 x 8 inch posts for a farm type heavy wooden gate just over a year ago and one of the posts now has a crack running down about 50% of the length and around 1 inch deep , possibly with a hairline crack running deeper.
A long time ago I learnt the lesson of wooden posts rotting first at the air/soil boundary and on subsequent installs of wooden posts I took the concrete fixings above soil level and fashioned the slopes away from the posts. This did significantly extend the life of fence posts.
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