"Chris Hogg" wrote in message
...
On Fri, 31 Oct 2014 17:47:27 +0000, MM wrote:

For a couple of years the back fence (8 ft high) has been getting
increasingly wobbly in the wind, as one of the fence posts is loose in
the ground and allows the fence to move in the wind. The post may
either have rotted, or maybe just the movement caused by the wind was
enough to loosen it more and more.

So I'm going to get a new, treated fence post on Saturday (from e.g.
Baytree or Andrews) and will place it near the loose post.

I plan to dig the hole for the new post using my grubber, spade,
garden fork and whatever else that comes in handy. (I also have a
crowbar.)

I won't have much room to work, because, of course, the posts are
tight up against the fence.

Now, putting the new post in: Would it be best to prop it up so that
is properly vertical, then fill around the base with concrete?

Or should I just fill the hole with the earth I removed and tamp it
down?

And how deep should the post be inserted into the ground? These are
very sturdy posts (10cm x 10cm). None of the others shows any sign of
becoming loose; just this one particular one.

MM
IIRC the recommendation is that a post should be half as deep in the
ground as the fence is high. i.e. a 6ft fence should have its posts
buried 3ft deep. I find this a council of perfection and difficult to
achieve in reality, so get as near to it as you can.

As for concreting, use postcrete^ or postmix*. This is a dry concrete
mix, that you just pour as powder into the hole around the post, tamp
and shake it down to compact it a bit, then water it well with a hose
or watering can. It sets firm in a few minutes. It's a good idea to
have the concrete coming up a bit proud of the surrounding earth, by
an inch or so, and finishing off the top surface with a trowel so that
rain water runs off, away from the post. This helps keep the post from
getting too wet and rotting.
^ http://tinyurl.com/kc8jz2b
* http://tinyurl.com/mroklw8

Makes more sense to use galvanised steel posts IMO.