Cutting the top rail of a chain link fence, or other options?

[winchman]

We need to replace a line post on a six-foot tall chain link fence with one that's a larger diameter. The new post will extend above the top rail, so a short section will have to be removed so we can install caps and strap clamps on each side of the new post. The new post is going in the middle of a twenty-foot section of fence. The new post is necessary to hold the rollers for a cantilevered gate.

The top rail appears to be in quite a lot of compression from the tension of the fence fabric. How should I go about cutting the top rail? Should I weld a brace around the section that's going to be removed before I make the cuts, or just remove the clamps on one end to take the tension off the fence fabric?

The other option is to fabricate some brackets to hold the rollers to the existing post. That approach would avoid cutting the top rail and replacing the post, but it wouldn't look as neat as having a new post of the correct size.

The existing post is 2 3/8" diameter, and the new post is 4". The rollers are only made to fit a 4" post. The upper bracket would have to extend above the top rail, but that's not much of a problem to do.

[Black Forest]

In my experience your easiest and fastest way will be to unfasten the fence fabric completely and get it out of the way. It is only twenty feet of fence, correct? You will spend more time trying to work around the fence fabric than it will take you to re-install the fence fabric.

[Normanv]

Why not just put the new post in next to the old one?

[winchman]

OK, here's the fence. Taking down the fabric entirely isn't an option. We cannot install a new post into the ground because there's concrete in the way, and we don't want to have to jackhammer through it like the fencing company did.



Here's the existing gate posts with the rollers.



Because of a snafu in the contract (which was impossible to correct or alter), the gate opening is too narrow for the truck and trailer traffic that will routinely use it. We're going to cut the left roller support post off at the ground and cap it. We're going to cut the line post off several inches above the ground, weld a plate around it, and weld the relocated roller support post to the plate. We'll then add a ten-foot extension to the existing gate over to the relocated rollers.

New idea. Rather than deal with the top rail, I'll just notch the 4" post to fit around it. I can weld a piece of square tubing into the notch to close the opening and keep the strength. The upper roller will attach above the notch.



Do you think that'll work?

Oh, that's our new outside covered work area behind the welding shop. I should rate at least one "ya suck" for having all that space to fill up.

[Paul Alciatore]

Seems easy to release the tension there by removing the end clamps on the fence fabric. Then just push a couple of feet of the fabric out of the way and replace the post.

[koda2]

I am not a gate engineer but here's my recommendation. Start over and do it right.

Reasons:
1)The new gate will be, what 6,8,10 ft longer? It will have to be beefier in design, especially if cantilevered. The existing gate structure, IMHO, will not hold up.
2) The gate will be opening and closing routinely and will wear out long before the fence does.
3)If you have cobbled it up or altered the structure, your company is responsible for fixing it, not someone else, plus it won't look as professional.
4) There is a bit of a grade on the fence line and that will have to be taken into account on making a longer gate.
5) A portable concrete saw and a few minutes of jack hammer work will pale in comparison to the cost and struggle over time to keep the current altered system functional.

I go into and out of a similar cantilevered security fence sometimes several times a day. The gate is built wide enough to handle tractor-trailors and large trucks. It is much, much stouter and it still gets some kind of maintenance every few months.

If you can't work with the existing fence company in a cordial fashion, hire a new company and build the gate the way you want it. Then reconnect the fence. Over the next ten years, everyone will be much happier.

Dave A.

[Black Forest]

OK after seeing the pictures I know what I would do. Before cutting out the post which is now the left post for the rollers put a come-along on it to the other post with the rollers that will remain. That will take the compression off the top rail that runs to the corner on the right. Then just cut your top rail an put your new post in. This way you wouldn't have to release the fabric at all.

[projectnut]

Take a closer look at how the top rail and fabric is connected to the posts. We have an almost identical situation and I remove the fabric and top rail on an almost annual basis to trim shrubs that have grown through it. The end caps on the top rail have a tab. The tab has a hole through it so a bolt can pass through the clamp on the post and the tab on the rail end cap. The rail retainer on the shorter line post has a self tapping screw through it to the post. The 20' piece of top rail is only in place by 2 bolts and a self tapping screw.

The fabric is held to the end posts by 3 of the same style clamps that hold the top rail in place. In this case they are attached to the metal strip in the second or third weave of the fence material. Just disconnect the bolts, disconnect one end of each wire that holds the fence to the line posts and top rail and roll the fence back. It takes me less than half an hour to remove and replace the top rail and fence fabric for a 20' section of fence. I spent more time in the past trying to work around the fence and top rail than it takes to remove it, trim the bushes and replace it.

I do buy the retaining wires by the bag from the local fencing company. They usually only last for a couple times of untwisting and re twisting them before they eventually break.

Before just cutting off the line post investigate as to how it's secured in the ground. In most cases fencing companies cement in corner and gate posts, but only drive line posts into the dirt. If it's cemented in it might be strong enough to support the weight of the gate. If it's only driven into the ground I doubt it will last a few months before the action of the gate causes it to tilt one way or another in the hole.

Consider just either pulling or cutting off the line post and replacing it with a larger diameter corner post in the proper place. You can easily core drill through the concrete or asphalt. Make the hole large enough to use a manual post hole digger to get a hole large enough in diameter to cement in the new corner/support post.

Also keep in mind the post and top rail are galvanized. When you weld on them you'll remove the galvanizing and eventually they'll rust. I would think it would take less than a day to properly remove the top rail and fence fabric, remove the errant posts, replace the line post with a corner/support post, cement it in place, and reinstall the fence. You could make the necessary changes to the gate before any work is done on the fence itself. Then when the post portion of the project is complete the gate can be rehung without any loss in security.

[winchman]

Well, I got one gate extension done, and the bird's mouth on the post worked out well. It turned out that the line post I had to remove and the top rail was offset from where the relocated gate post needed to be.

I cut the gate post off, and capped the opening. This area will be paved over in the near future.



I put a temporary support under the top rail, removed the line post, and added a plate for the relocated gate post. You can see the chalk marks that show how the gate post needs to be offset.



I cut the notch in the gate post, and welded the insert in place.



It fits nicely around the top rail.

[winchman]

It looks neat enough from inside the fence, too.



I added the extension, and installed the rollers on the relocated post. I put short sleeves inside the pipes to aid in getting them aligned.



I haven't been able to test it because they didn't leave me a key for the lock, but I'm confident it's going to work fine. I still need to install some ties on the fence fabric and barbed wire, and install some stops.



The opening is almost seventeen feet now. The gate itself is a little over twenty-seven feet.

I'll fix the gate on the other end next week.

[craigd]

Good job. Thank you for sharing.