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Toilet pipe not level with subfloor

Author: halfmassive (IL)

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.

Thanks!

Here are a few pics:

Re: Toilet pipe not level with subfloor
Author: HelpMePlumb (FL) Pull off the galvanized metal and frame it up flush with the existing subfloor. Done.

Re: Toilet pipe not level with subfloor
Author: hj Take the metal off and put the plywood over the hole. If you are using 3/4" plywood, it does not need a "subfloor" anyway.

Re: Toilet pipe not level with subfloor

Author: halfmassive (IL)

The problem with just putting the ply right on top of the pipe are is that the pipe does sit slightly proud of he sub floor. If I build up he sub floor with ply wood could I jus cut a notch in one sheet of 1/2 and then later another another sheet of 1/2 on top of that?

The other option I'm contemplating is using 3/4 ply cuttin out a notch for the pipe and then filling that area with mud or thinset to make it flush with the 3/4 and the. Putting cement board on top of that. Could this work or would I have some issues with the ply and mud bonding with each other?

Thanks again for the advice I really appreciate your time and help.

Re: Toilet pipe not level with subfloor
Author: hj The pipe SHOULD be above the finished floor so it will be flush with the top of the new flange you will have installed.

Re: Toilet pipe not level with subfloor
Author: sharp1 (IL) Pull the tin off so that we can see what you are describing. Is there a hub under the tin holding it up or is the pipe running uphill towards the wall?

Re: Toilet pipe not level with subfloor
Author: Paul48 (CT) The way I read it....he doesn't want to use that pipe.

Re: Toilet pipe not level with subfloor

Author: halfmassive (IL)

Thanks again. I do want to keep the pipe where it's at since cast iron is out of my skill set and also my budget. I went to the house and forgot my camera but took some measurements. The pipe for the flange is about 1 1/2" higher than sub floor. The problem is the horizontal run of pipe behind the flange section. As you can see in the pic it is about 1/2 higher than the sub floor. The tin or steel plate makes it look more deformed than it is. The horizontal run of pipe sits right underneath the plate.

I still think the easiest fix would be to notch my new 3/4 ply and use deck mud or thinset to fill the void around the hump to be flush with the ply and then top the whole floor with 1/4 cement board. Does this sound stable and doable? I think my only other option short of a new pipe is 2 sheets of 1/2 ply - one with a notch for the hump and the other solid and then topping that with the cb.

Any suggestions?
Thanks very much

Re: Toilet pipe not level with subfloor
Author: hj relieving the bottom of a sheet of 3/4" plywood, for the little area the hub would take would NOT diminish its strength in the slightest. What you after the plywood is installed depends on what you WANT to do, NOT what you HAVE to do.