Pressure treated 4x4's in the ground -- what to treat them with to make 'em last?

[Raspy]

As mentioned earlier, coppergreen is the ticket. You can even use this on untreated wood and it will last for many years. Also, if you use pressure treated wood and cut it you will have to treat the area that was cut because the treatment only goes in so far. Use copergreen for this too. Excellent.

Either ask for it at the hardware store or Home Depot. Also called Terminate.

The bottom of your posts should not be capped in concrete, but against gravel or sand or just the ground.

 

[/pine]

As mentioned by several others...Pressure Treated lumber is graded for ground contact...
Some "PT" is only meant to have "casual" contact with the ground...other "PT" is meant for subterranean applications...

Copper Naphthenate used to be available...not sure if is still legal to obtain...

I always found it interesting that they use copper to preserve wood...but copper (as in a large nail etc) will kill a tree...

 

[whistlepig]

Dig the hole and put the post in. That's all that is needed. I pour 120# of Sackrete around my corner posts and 60# of Sackrete around my line posts. I then pour water on the Sackrete and let it set up for a day. Then fill and tamp the dirt. Or you can look at what the pros do at Redbrand Fhttp://www.redbrand.com/installation/index.aspence.