On Wed, 19 Jan 2011 11:17:17 -0000, Charlie Pridham
wrote:
snip
I would say that it is a toss up whether the the metal post bottoms rust
out or the posts rot before 10 years are up I had replaced the 4x4"
tanalised wood posts on my large pergola 3 times in 27 years before I
gave up and built masonary posts with reinforced concrete cores
I know I live on the wetter side of the UK but the disruption to the
garden at each rebuild was very annoying and it worked out a lot cheaper
to build masonary in the end for the size of the posts

I can only repeat that I have Metposts that are 20+ years old and
they, and the posts in them, are perfectly sound (and as near
perfectly vertical as dammit save for one which was deliberately
skewed to get around a tree on the other side!). I had to replace some
fence panels that were damaged by wind last year but that's all. I
make sure that the bit of the spike that holds the post is above
ground - I've seen some driven right in and maybe that is why they
fail - rust at the weld between the spike itself and the "container"
on the top.

Cheers
Jake