Level fencing

30 Mar 2015
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United Kingdom

I have a 12 metre deep garden which is on a slight decline. It slopes away from the house. this isn't particularly pronounced but is the case and actually helpful for water to drain away into a joining field.

I want to erect my fencing and would like to go for 5 ft high fence in this style:

Question, how can I install this so that the top of the fence is level? I don't want it to follow the slope of the garden and nor do I want to step it every few panels. I am happy to put additional gravel boards for instance.

Thanks in advance.


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Additional gravel boards is the way to go. Just install the posts by trimming the bottom off so that the tops are all level. Then infill the gaps at the base with gravel boards which will need to be either trimmed or better if they are sunken into the ground.

You may need to use deeper posts if the ground slopes significantly as you will run out of length as the ground drops away, your post holes need to be about 18''
Thanks for the response @r896neo.
I can envisage this approach if I was using lap panels with regular square posts but the fencing I want to do as per earlier picture, has these rails that go across and slots into the precut triangles in the posts. How will the suggested approach work for me?
What is the height difference from one end to other?
An approximate way of extending a level line, apart from using a proper tool, is to use a level at the top end, set on something so that it is level, along the line of the slope. Then using a string line stretched between top and bottom, fixed at the top along the level, move the string line up or down at the other end, until it runs parallel with the level.
Then measure from the line to ground, and deduct the height of the level at the top end, if it's above ground level.
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If the top of the posts has to line up, then the triangle cuts will have to line up also.That means the length of post below the bottom triangle will need to be variable by cutting or the hole depth be varied .
Can you get the posts cut as a custom job or cut your own notches or are there versions of the posts for a higher fence available?
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As tony says you either trim the bottom off the post or you get a post that I longer. The notched posts are not available where I am so don't know if longer ones are available with the same notch pattern?
If the position of the notches is an issue, just use plain posts and arris rail brackets.
It feels to me that I can only do what I am trying to do with square posts and then use the arris rail brackets. Anything else (short of cutting the triangles myself) wont work as the triangle cut outs wont line up.

Next question - are the brackets as robust as the cutout's or can I easily do the cutout's if this substantially increases the strength of the fencing?
The brackets are galvanised and robust. If you are unconvinced, fix them with (decking - e.g. Screwfix Turbogold XT) screws and then they are easily replaceable.
I am guessing Turbogold are rust resistant?
Some further questions please:

- When I fit in the arris rails in between the posts using these brackets, should the face of them be flush to the outside of the post so that the slats continue through uninterrupted or should they be set back so that the posts are visible? I hope this makes sense

- If this is the approach I am taking, should I use arris rails (triangular) or rectangular cross sections? I think they are called Cant rails. If yes, are there brackets available for these too?

- Finally, how can I be certain that when I nail on the slats, the overlaps will mean that I don't have a small gap left at the end when I am joining the post? The risk of this makes me wonder whether the cross sections should be flush with the post as suggested above.

Thanks in advance.
Yes, I always do them flush with the posts. I've never seen brackets for cant rails. Arris rail brackets should be about 80p each.

It's not just rust resistance per se. The coating on decking screws is non metallic to better resist the corrosion that you get from the preservative in the wood.

Btw typically, 5*3 posts are used rather than square.
That's great.
Final question - how do I get a straight horizontal line for my fencing? I don't own a laser level.

So, when all then posts are in, how do I determine where to pull the string and position the top of the panels? I've tried using the spirit level against a string in the past but find this very inaccurate.
You need to buy or improvise a water level. A hosepipe with a clear container mounted at each end will do. Mount the uphill side at the level you want to start from and take a guess at the other end using stakes of some sort.. Fill with water and see if the downhill side overflows or is a no show and adjust the height accordingly. You may have to wait quite a bit of time for the levels to equalise if it's a long run.

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