"The Medway Handyman" wrote in message
o.uk...
It occurs to me that any wooden post concreted into a hole in the ground
is going to rot eventually, tanalised or whatever - it's got to be a
matter of time.

The worst area is going to be the end grain by my reckoning, since end
grain is the most absorbent and is going to absorb moisture faster than
any other part of the post.

Soaking the end in wood preserver is one option, but are there others?

A couple of inches of gravel in the bottom of the hole would provide a
natural drain, but might weaken the installation.

Wrapping the post in a plastic bag could work, but again might weaken the
installation because the concrete wouldn't bond to the post.

Piece of DPM in the bottom of the hole?

Any thoughts?

Solutions I have used:

1) Use concrete - lasts about 60-70 years, to judge from the age of the ones
I had to replace.
2) Use oak - not a lot more expensive than pressure treated softwood and no
signs of any deterioration in the supports 10 years after I built a pergola
of it.
3) Wrap the post at ground level - a bit below and a bit above - with the
bitumen backed foil sold for flashing repairs. I find gentle warming with a
hot air gun on the bitumen side before application makes it stick and seal
very well. Adds, perhaps, a couple of years to the life of an ordinary
wooden post.

Colin Bignell