Anchoring a garden arch

[Steve Maskery]

This was triggered by Steliz's post.

I have laid a new garden path from the house down to the workshop (well, I have laid it out, no granite chips yet as the supplier has been closed for the last three months, but you get the picture). I would like a garden arch at the bottom end, not quite a pergola but a bit more than a bit of trellis. This sort of thing:

Whilst it will be fairly sturdy, I don't want any chance at all of it being blown over in a storm, so I need to decide how to anchor it. I plan to sit the four feet on slate pads (I have lots already), but they still would not be anchored.

I was thinking of drilling a hole in the slate pad (~20mm thick) and having a piece of rebar into the the bottom of the upright and into the ground. Does this seem sensible or would it be a case of "It will last 5 minutes, Steve"?

Experiences welcome.

 

[Trainee neophyte]

I have a similar thing all around my house, 15 years old, and the uprights are all still sound. I assume that this is because they are all raised 2" off the ground by metal brackets. I have failed to find exact examples on the internet, but they look a bit like this:

Mine are more wrought iron than industrial stainless steel, but they keep the bottom of the wood away from the ground, and the insects.

The horizontal timbers are all rotting out - a combination of sun, plants to trap moisture, lots of winter rain, and being flat on top which allows the rain to collect in the cracks (it's all cheap, pressure-treated pine, so full of shakes, or is it shivers?) Luckily they are 4 metres up in the air, so no one can tell.

Next time I may round over the tops to try to shed some water - not sure if it would help. Some roof tiles would be better, but your thing would end up looking like a Chinese temple entrance (would that be bad?)

 

[Steliz]

This was triggered by Steliz's post.

I was thinking of drilling a hole in the slate pad (~20mm thick) and having a piece of rebar into the the bottom of the upright and into the ground. Does this seem sensible or would it be a case of "It will last 5 minutes, Steve"?

Experiences welcome.

If you put a medium sized lump of concrete on the end of that rebar it will be solid as a rock.

 

[Steve Maskery]

I'd not actually thought of that! I was more worried about the rebar rusting through.

 

[MikeG.]

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The fifth one is what you want. It raises the foot of the post off the ground, and it doesn't have any horizontal "shelf" for water to sit on. I try to make the bolts a bit more subtle than that, and have the horizontal plate under the post foot smaller than the cross section of the post so it's not visible. For a top job, let it into the bottom of the post. I don't have adjustment (as per 4) because that also allows twisting, which oak will do at the drop of a hat. You just have to put them in position properly.

 

[Steve Maskery]

That is all fine for preventing rot and all that, very good, but it doesn't address the issue of actually anchoring the thing down so that it doesn't blow over in a storm.

 

[MikeG.]

That's bolted to concrete, Steve. Or better still, cast into the concrete.

 

[Steve Maskery]

OK. But mine will not stand on concrete. I have soil. I also have some substantial green slate pads, like giant pitas, a good 12x8".

So the layers are Soil, Slate, A.N.Other, Post.

 

[MikeG.]

You dig a little hole, the size of a small trenching spade, square (so 9 to 12 inches square), and maybe 12 to 15 inches deep. Fill it with concrete to just below ground level. Insert your post foot shoe, and wait for it to dry. A nicely marked up batten (or bigger) helps line up all the steelwork, and you tamp down the concrete when everything is properly in place.

 

[Doug71]

I put one up for a friend the other day, was a real cheap kit that didn't fit together properly.

It came with four of the metpost type spike things, the metposts were for 75mm and the arch legs were 56mm so they needed packing round.

I give it about 3 years.