Pergola - Fixing to the ground

[vonsworld]

Hello

I’m planning to build a Pergola in a corner of my garden as a support for Wisteria and am considering how to fix it to the ground.

It will be a free standing Pergola with 4 legs and about 8ft square in size.

Obviously I could just concrete the legs into the ground like a fence but was thinking of other options that would make it easier to move or repair the Pergola in the future especially if the supports eventually rot away.

How about concreting steel fence post supports into the ground and then simply inserting the posts?

The posts might wobble a little in these supports but I assume that once assembled the 4 legs and structure of the Pergola should make it firm and stable.

Perhaps even easier how about burying 4 pre-made concrete blocks in the ground and then attach the posts to these using steel brackets and concrete bolts. Since the Pergola is an open structure that doesn't catch the wind too much, would this be enough to hold it in place?

Finally how about just using post spikes with no concrete, would these be strong enough?

Your advice is appreciated

 

[blup]

Post spikes are a quick fix IMO not a long term solution, the concrete blocks buried in ground is over engineering the solution which leaves burying the posts in concrete or attaching to spurs.

Spurs will protect the wood above ground but the overall appearance will be compromised.

I would be minded to bury direct in concrete using treated timber, the whole appearance of the pergola will change significantly within a few years in any case.

Blup

 

[ETAF]

ignore wrong post

 

[JohnD]

I have a comparable carport and shed where I used steel post sockets, bolted to concrete blocks in the ground.

only the top of the block is visible, and you can use formwork to make the top few inches a neat square not much bigger that the steel shoe.

Unlike a fence, the legs are not subject to strong sideways forces trying to blow them over (the post sockets are poor for that) and the concrete mostly has to resist weight, so does not need to be as deep as a fence post.

In my case, I used dark brown masonry paint on the concrete, and corrosion resisting paint on the sockets, and stainless bolts and nuts, to blend in with the dark stain on the legs.

My posts are protected from rain and not in contact with the ground, so will probably last longer than I will, but if necessary they could be removed and replaced with new, or the blocks dug out.

I think my steel sockets might be structural, they are thicker than the post spikes I tried before (which have rusted away)