Originally Posted by Robdude
Two questions really. First, the fence posts I've got aren't very stable anymore. They move back and forth easily.
It looks like they were set in cement or concrete (I'm not sure what the difference it) but it's like the wood is smaller now or something and moves around inside the hole - if that makes any sense.
Can I just pour more mix down there - or do I need to dig up the whole post?
Secondly, I have some pressure treated lumber I was using on my deck it is 5/4" thick, and 6" wide. Can I use this on my fence?
Usually when a wooden post gets to feeling like it's smaller, it is because it is. Water gets down between the post and the concrete, and creates an environment for rot to begin to develop. Rot (mold) feeds upon the wood. It's a living organism that actually eats (well, more like chemically "absorbs" the fibers) the surface of the wood.
It won't just go away on its own. It will keep eating away at the post until the wood finally crumbles or snaps from pressure applied to the fence... usually by wind. The posts need to be replaced with new posts that have been coated with something that will keep the water from the wood... tar, pitch, creosote, etc.
Wood can get wet, no problem. But it cannot STAY wet. It has to be given a chance to dry out. Above ground, the sun and wind help with the drying process. But underground, it can't get dry, so it rots.... UNLESS protected as I mentioned above.