Hi, this is my first time posting on this forum, but I have come to it before, looking for answers. I have been installing tile for a long time, it's what I do for a living. Right now, I am in the middle of a job where I have torn out the old tile, and mud-bed, in a bathroom and discovered several "floor coverings" under what was there. The house was built in the 20's, I believe, and this bathroom was an after-thought. It appears to have been built partially on part of the porch, so there are porch pavers, a strip of bricks from a foundation wall, some pine boards and some vinyl or asbestos tiles that leave a tar-like substances behind when you pull them up. The floor is pretty out of whack in terms of level, as you might guess. I am looking for suggestions about the best way to approach leveling this thing out, and getting it ready for some really cool marble.