So…when we first moved in (~15 years ago), the yard was a blank canvas. New build. It’s still not done, but one of the things I did was drive 6 metal fence posts into the ground (the kinds with the nubs), and ran three wires between them to serve as a trellis for grape vines. We had grapes at our old house, but for some reason we never could get them to fruit here. Regardless, over the years the wire has sagged a bit.
I went out and tightened them up, but I think the root cause is that there is no opposing force on the two end posts. The wire just pulls inwards unopposed. I know the solution the city has for wooden power poles in that configuration: embed a thick steel post (probably in several feet of concrete) and attach the end post to that. My application is much smaller, and I’d rather not have to dig a hole big enough that the concrete won’t move, and mix a bunch of concrete, to put an anchor in the ground to supply the opposing force. But maybe I have no choice. Is there an alternative anyone can think of? Just putting another post won’t really solve the problem, I don’t think. The only solution I see is to dig at least 2’ down, dump concrete, position a metal anchor, and when it is set and hard, tie off the end post (two of them…one on each end).
Do the metal posts have channels like this? How were they set? Just driven in, or in concrete?
Two feet of cement sounds like overkill to me. How about taking a post like that and driving it in at an angle, leaning away from the existing fence. Drive it in about as deep as you can make it, then secure the bracing wire at the soil line. Another couple of wacks, then cut the post off at the ground level.
Or maybe a ground spike like this, with six inches of 4x4?
I might also consider chain rather than wire. With turnbuckles.
I think you are putting the solution on the wrong side of the end post. Put a much smaller blob of concrete - (go for diameter) so the tension in the wire is pushing into the ground, not pulling out.
Wire fences are common, and preventing sagging has many solutions
A common technique is to drive two posts, and put a third post horizontal between the two, near the top.
Like a H
Called Horizontal H brace.
This usually has a wire angled between the uprights, too. Sometimes the wire is wrapped around the uprights at the height of the horizontal post.
Step 9 in the H-brace, link.
Another common technique is to drive an “end” post, then drive a brace post, on the tension side, at an angle from ground level upward against the top of the end post.
End post, brace post … Tension side.
I
Called a Floating Brace at the link.
There are lots of variations.
I’ve seen two uprights with X wires between.
Long wire pasture fences often have a “brace” at regular intervals.
ralph
For whatever reason, TMF will not let me insert an image. Hmmm.
Yes, the posts were nubbed, and -as I recall- did have that flange that was driven into the ground. I drove them in with a post driver (heavy metal cylinder that you whack the top of the post with). No concrete. Today, I’d do concrete. Back then, I didn’t think about that. I thought driving about 2’ into the hard clay soil would be good enough.
It’s possible the posts have slightly bent over time. They don’t look completely straight now. I’d have to put my level against it to verify (I may do that, but it won’t make any difference at this point).
I don’t think a simple spike will be enough. I could -as suggested- drive a smaller post (at least 2’?) at an angle, and then tie it off near the ground. On one end it would be a tripping hazard, but on the other it would be less so.
Go to Amazon, search heavy duty ground anchor screw in. It will hold hundreds of pounds of tension, and all you have to do is screw it into the ground once. (Buy a piece of rebar or other metal pole to give yourself torque). They can be used to hold up a large awning tent, shed, or other edifice without a foundation; I’m sure they’ll do for a few fence posts.
Put a turnbuckle in the line between the fence post and the ground screw, and adjust it as necessary. You may have to tighten it up every year or so, depending on if the ground shifts under the posts.
