I have a slope and my fence installer only dug down into the clay hardpan 1.5 feet for a 6' fence. He put concrete in the hole but I think it's way too shallow. Since the land slopes I am thinking of building the area up with soil around the posts which would add the needed depth but I don't know if I should use concrete around the posts, since it would need to bond to the concrete just poured this week. Any ideas? Make a shorter fence or pull them out and start again?
Only 1.5’ down for a 6’ fence is unacceptable. The first wind will cause the fence to lean...then eventually fail.
Adding soil to the top is pointless. You want the posts in undisturbed soil.
I’d remove it and start again...minimum 30” down.
Yes. Piece of mind says redo this with 30" depth posts.. You'll be happy you did.