Pergola Anchoring Considerations

[Egmel]

Hi Guys,

I'm thinking about getting one of these jobbies http://www.edecks.co.uk/shop/product.aspx?pid=2053
but I'm a bit concerned about how to anchor the posts.

My first thought was to concrete them in, but then I wondered how deep they would need to go. Other posts on here suggested 12"-18" but when it's only 2.4m (7'10") tall to start with, I realised that if I did that I'd be loosing the height and would likely end up with something where I'm going to hit my head on hanging grapes! (I'm 6' and my bloke is 6'2" so he'll just hit his head on the beams ).

So I then started looking at concrete embedded post anchors, but they all appear to be for square posts and these are round! Plus I'm not sure that they're suitable given the height of the structure.

Finally I started to wonder if I could concrete in some short metal posts and then bolt the pergola legs to them.. this seems to be the best option so far...

Any other ideas or suggestions on how I can attach these 70mm round posts to the ground without losing too much height. My soil is ex-allotment so the top 2' is lovely and sandy, great for gardening, useless for bedding posts in, even the bird feeder caused me trouble!

Cheers
Helen

 

[merlin50]

it is erected by simply digging the uprights into the ground.

simples

 

[Egmel]

it is erected by simply digging the uprights into the ground.

How deep? any more than 6" will reduce the height too much but I don't think 6" will be enough for it to be sound. My soil is too sandy to be secure on its own, it would need to be concreted otherwise when the wind blows it'll end up down the garden taking the plants with it.

Simples if I were 5'3 and on a clay soil, as it is, not so simples....

 

[freddiemercurystwin]

They should be concreted in so the posts need to be longer, about 18" will be OK but maybe deeper if the soil is poor. Wouldn't take much handy work to make it up out of timber from a merchant rather than buying a kit.

 

[ladylola]

I'd just go with merlin to be honest and not bother with concrete,, at 7' 10" you could still get a foot into the ground and have headroom.
That said if you are really kean on concrete but are also really worried about there not being enough in the ground then there is a simple solution.
Fix metal strapping to the bottom of the posts , screwed would be fine and then concrete into the hole.
This sort of thing -
http://www.screwfix.com/p/roll-edge-restraint-strap-bend-500-x-100mm-pack-of-5/85398
cut to lenght and about 3-4 to each post would do the trick.

 

[Egmel]

Wouldn't take much handy work to make it up out of timber from a merchant rather than buying a kit.

True, but I've not seen the rounded posts at our local timber merchant (Champion Timber Guildford - happy to try others if anyone has a recommendation).

Though I have just discovered that the kit isn't pre-drilled so full DIY is now a more viable option if I can do it within budget as it won't be any more work.

 

[Egmel]

Fix metal strapping to the bottom of the posts , screwed would be fine and then concrete into the hole.
This sort of thing -
http://www.screwfix.com/p/roll-edge-restraint-strap-bend-500-x-100mm-pack-of-5/85398
cut to lenght and about 3-4 to each post would do the trick.

Oooh, now there's an interesting solution, half way between concreting it in and the metal post idea...