How to prep and level part of my garage when there is a 6" difference in hight?
I’ve used Gypcrete over concrete slabs and various wood structures.
I think it’s rated up to 8” thick per lift. However, it can’t be walked on, etc. because it will wear. You’ll need provide a covering.
It goes in like tomato soup, so it will seek its natural level. It hardens in a couple of days.