On 22 Feb 2007 15:02:04 -0800, "
wrote:

Tim

At least Phil offers a sensible sollution to your dilema. However dont
worry too much about making up a week concrete. It will resist water
better if made stronger so you will get more time out of your fence.
In addition bring the concrete slighly above ground level in a cone
shape so that water runs off.

I built a carport recently. I read and was told that if you set a
wooden post in concrete the worst rot will happen in the post just
above the top of the concrete.
Assuming that you do some decent concreting the section of the wood
that will be stuck in the concrete will be quite protected and stay
healthily moist and the worst rot will happen where the concrete ends
and it isnt quite dry or wet. Additionally it rots worse if you do the
concrete so it can puddle round the post.
Looking at my wooden posts I can see where they change from wet to dry
just above my concrete.

I set my posts by digging a hole and putting a 6 inch concrete base in
it (normal wet mix even if it is underwater works fine). Leave that to
set then drop the post onto it. Fill round the post with normal wet
mix concrete and like Calum says bring the concrete up the post to
above water level and slope it so the water runs off.

An alternative (so long as you or your neighbour isnt growing veg next
to the fence) Is to soak the ends of the posts in used engine oil for
a few days prior to putting them in. This greatly increases their
life, and any garage will give you some for free. You can then take it
to a car breaker, or back to the same garage for them to dispose of.

I also did this. Get buckets or whatever you can and leave the post
standing in it for as long as possible. I only had a couple of days
and a big post standing in around 2 inches of engine oil soaked it up
to 4-6 inches.