I've seen different recommendations online so I'm looking for some clarification. I'm building a 4' tall chain link fence.
1) Do the terminal and line posts need 4" of base gravel in the post holes? I understand the need to do this for wood posts so they don't rot, but I don't know the reasoning for the galvanized steel posts. Some sources say you need the gravel.
2) Do the line posts need cement? I know the terminal posts need it, and most sources state that the line posts should have it too, but I've seen it both ways.
3) The fence I'm installing is replacing an old rotted wood fence. The previous owner had soil against the wood fence in some spots, which created a 6" drop from one side of the fence, to the other. Should I flatten this area, or should I just install the fence in the same spot as the old one? See drawing below for clarification.
Best Answer
The point of the gravel is not just for rot prevention. You want to dig down below the frost line, first and foremost, so that any water below the post won't freeze and heave the post out of position.
The gravel below the post allows water a place to pool until it eventually drains away completely. If you put the concrete directly in the ground then water could gather around the concrete at or above the frost level and cause heaving to the side. Having that extra drainage helps prevent that.
So in general it's a good idea to put gravel in ALL your holes. Critical? Not necessarily.
Your last question - kinda hard to visualize and definitely on a different topic from the first two. You may want to split that part out to a new question.