On Dec 23, 11:28*pm, "Brian G" wrote:

That is untrue, I have seen rotten tanalised timber - and in fact, the life
of such timber in certain circumstances is around 5 years.

Tanalising has become a bit of an abused generic term to mean anything
dipped in a vat of green liquid. It should mean something treated to
the Tanalith process and spec.

Nevertheless, AIUI cut ends should still be treated so even the real
deal is not totally fule proof.

And one of my joys was calling a rather arrogant rep back five years after
using his firms so-called "guaranteed for ever" treatment, to show him a
lovely piece of joinery thoroughly rotten and totally useless - that's life.

AFIAK, the best preservatives are based on copper and give the wood a
nice green colour. Most anything else will leach to some extent,
especially from end grain.

Sikkens recommend in their bumph that joinery be given a coat of stain
*all round* before assembly, this would help minimise leaching (but
adds a little to time and cost)

I usually give hidden surfaces a coat of water based stain, dries in
next to no time if the wood has a low MC.

cheers,
Pete.