First post but I've been reading the topics here like crazy lately. Already this forum has been a life saver!
I am mid way through a demo and renovation of a 1950s bathroom and have run into a problem.
The original floor had a 1" or so mud floor and unfortunately I wasn't able to save it. After tearing it out to the subfloor (12" planks) I have found that the toilet drain pipe (not sure of the exact term) which is the original cast iron does not sit flush with the sub floor. The original builders put a tin cover over this and there is a noticeable hump where this occurs. I assume this wasn't a problem for the original builders because it would have been mudded over and then leveled out.
I was planning on using 3/4" ply topped with cement board and then tile on that.
Now I can't lay my plywood directly over this raised area, so would my options be. I thought about cutting a notch with the plywood and then using some sort of mud or concrete to fill in the notch so I can tile on that. Another option I can think of is using 2 sheets of plywood with the notch on the first layer and them solid sheet on the second layer.
I don't have much experience with mud/concrete so I am pretty clueless about the best way to correct this, but would appreciate the help.
Here are a few pics: