Putting posts in the ground

[DTR]

Afternoon all,

Doris has asked me to build a pergola later this year. She wants to put plants around the perimeter so there won't be a concrete slab or anything of that nature. What is the best way of mounting the posts?

Thanks

 

[riclepp]

I would use eithe metpost or concrete in individual post so that there is no concrete slab as such.

 

[Waka]

I would also use the met post., but I would concrete these into the ground, should the post need replacing at a later date then this is easily done. The problem with cementing wooden post straight into the ground is rot, with a few years they will break off at the ground.

 

[nathandavies]

If you really want to use something cement based use postcrete, it's sooo easy, but where I can I just compact the earth around the post, which allows water to drain away, and is obviously greener and cheaper

 

[DTR]

I was thinking of using metposts but I wanted the forum's opinion first. I wanted to avoid using concrete / postcrete due to the posts rotting. I have heard that simply burying the post in gravel then tamping the gravel down is usually good enough. The gravel provides drainage while still holding the post solid.


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[AndyT]

I'd use Metposts too. I used them for fence posts in our back garden and the oak posts are still fine 20 years later. Also, I found it easy to get them to go in vertical, even though they had to go alongside a brick wall.

 

[Jamesc]

I used stainless steel threaded rods (available from screwfix amongst others). One end was glued into a hole in the bottom of the post the other into concrete in the ground. I actually conreted in a socket (overflow pipe) I could then use a nut and large washer to fine tune the height of the post. I deliberatly kept the post 3" above ground level
I did this 6 years ago in a area of my garden that is under water every winter, no signs of rot yet.

James

 

[Mark A]

Would coating the bottom of the posts in something like epoxy prevent them from rotting if they were set straight into concrete?

When we put up our fence six years ago we soaked the ends of the posts in creosote before placing in concrete and they're still solid.

Mark

 

[AndyT]

Would coating the bottom of the posts in something like epoxy prevent them from rotting if they were set straight into concrete?

Mark

I don't think it would. An impervious layer round the bottom end would keep any moisture inside the wood, promoting rot, pretty much the same as the concrete does. You can't stop moisture getting in - the wind and rain will see to that - but by lifting the ends up off the damp ground they will have a chance to dry out from time to time.

Metposts help a bit, but now I reckon JamesC's approach would be even better as it would expose the wood even more - Metpost sockets are good but do act like an impermeable cap to some extent, even though they have some perforations.

 

[Tierney]

I was going to suggest met posts, concreted in, and to put a spacer of some sort between the end of the post and the bottom of the met post socket to help avoid sitting in water.

JamesC's approach is even better and is similar to how you see some installations in public spaces.

For either of the above approaches you will need to add extra support to avoid lateral pressure on the structure. Not quite full cross braces; but, I would maybe connect a piece at 45 degrees, at about 600mm along the horizontal and vertical members.

I just don't get why anyone would put a wooden post in concrete, just creating a problem for 5-10 years down the line.

DT

 

[Hemsby]

Hi,

There is almost no perfect way of setting posts. Wood in concrete, wood in Meta posts even concrete posts in concrete all have a downside and will fail eventually.

Generally Meta posts are used for convenience, concrete posts for strength & longevity but if the main consideration is appearance then wood wins hands down.

First choice if you only need perhaps 4 posts would be Oak, if the cost is not prohibitive. Alternatively my choice has always been “Tanalised” posts (normally 15 years guaranteed)

Place a piece of stone (not brick) that is wider than the post at the bottom of the hole as the end of the post is the most susceptible for water ingress then concrete. The other point is that the concrete must finish slightly above the ground level then with a trowel slant the top of the concrete away from the post.

Using post hole mix or dry mix concrete is a quick and easy way of setting posts but using wet mix allows you to ensure that the mix goes down and flows around the post and sealing around the stone at the bottom. You could also use a waterproofing additive to the mix

At my last property I set all the posts using this method an after nearly 15 years we left leaving a solid fence still standing. 2 years ago I set 160 feet of fencing using the same method. Long may it survive!!!!!

The wooden posts may after a while shrink slightly where they contact the concrete which some may say is open for water ingress, so when all is dry just squeeze clear silicone around this area.

As I said at the beginning nothing is going to be perfect all you can do is take as many steps as possible to help.

 

[Alex H]

I was thinking of using metposts but I wanted the forum's opinion first. I wanted to avoid using concrete / postcrete due to the posts rotting. I have heard that simply burying the post in gravel then tamping the gravel down is usually good enough. The gravel provides drainage while still holding the post solid.


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I've done this for our garden gate - fine after 8 years

 

[Bluekingfisher]

You will need to use crushed aggregate, not concrete, which will hold moisture and eventually rot the post at the base. Make sure and tamp it in, it will be rock solid and not move. You can then apply a layer of top soil to keep SWMBO happy.

David

 

[DTR]

Thanks guys

 

[wellywood]

This is what I use. The spike is concreted in and the post bolted in to the saddle just clear of ground level.

 

[MickCheese]

I'm not a fan of met posts. As soon as they hit a stone or something it seems to knock them our of plumb.

Setting them in concrete seems like a good idea but the post fixator above ground looks to be the ideal solution.

Mick