Quote Originally Posted by Steve Clardy View Post

If building a deck and setting pressure treated posts in the ground surrounded by concrete is a no-no, [First I have heard of this being a no-no] then what about a pole building [which is what I have] that is basically the same thing. 6x6 treated posts set 3' deep surrounded in concrete.
Curious Steve
Very common to install deck/fence posts with 4" - 6" gravel in the bottom of the hole (to drain water away from the post), then the post, then concrete. I seriously doubt there would be any problems within our lifetimes by using this method - plus is is one HECK of a lot easier than digging footer holes and cheaper than filling those holes with concrete. But - footers and brackets work well too, though bracket will fail before the post-in-concrete fails.

Be aware that there are now a number of chemicals used for treated lumber. The gold standard for 50 yrs +/- was CCA, but is no longer used for most applications - but it is still allowed for a few - including agricultural + industrial (read: pole barns + phone poles) and marine. Why? because nothing else works that well, and the big hoo-hah over the arsenic in CCA disappeared because, in the cold, sober light of actual science, there was no merit in the concerns. Negative PR caused the Borg to insist on a change from their suppliers.

Also - there are various treatment "levels" for any chemical, measured in lb/cu ft of chemical retained in the wood. Something like 0.15 lb/cu ft for non-ground contact (read: fence boards) all the way up to 6.0 lb/cu ft for seawater immersion (read: sea walls, dock posts, etc.). More chemical = more resistant to decay.

And - yes, I used to work in that industry. No longer, not shilling for them, just been in that rodeo. My info is a little dated, but should still be pretty much on target.