New Ceramic Over Ceramic

Old 07-05-03, 12:43 PM
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New Ceramic Over Ceramic

This is the situation. We remodel the bathroom first and installed Standard 12X12 ceramic tiles on concrete subfloor (foundation). Later we did the rest of the house. We installed 3/4" solid oak over 3/4" plywood subfloor. At the door of the bathroom there is a huge difference in height between the two floors and my wife says that that is ridiculous. We decided that since we have to fix the height of the bathroom floor, let's just go ahead and re-do the bathroom floor with another tile. Old tile is in good condition and is not loose or anything.

Question/s. I have a 1 1/4" height difference what should I do?
Do I have to remove the old tile to install two layers of plywood to bring everything to height? or Can i install either playwood or backerboard on top of old tile or both?

Question/s 2) If I install plywood and backerboard on top of it as a subfloor, where is the toilet bowl suppose to seat on. the plywood or the backerboard and will the bowl be way to high from the existing plumbing to still have a good tight seal?.

If I was not clear please let me know.

thanks in advance.

Old 07-05-03, 05:55 PM
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am i to assume that the wood was put on a sleeper system?it sounds like what you wopuld have to do is to sand/cement the bath floor andd bring it up to the needed heighth and then tile over that as you cannot put plywood over the tile then wonder board then tile.being in you should not have trouble finding the sand a fine to med. here in st.louis it is called meramac sand and plain ole ready mix cement.mix at a ratio of 4sand to 1 cement blend together then slowly add water and mix until you can make a ball in you're hand and gently bounce it in you're hand a nd not fall apart.Lay some wire mesh over the tile that is in and bring the floor up to desired heighth throwing the mud on the floor and patting softly to pack it and using a level or a straight peice of wood screed the mud level across the floor.If this sounds like too much there are plenty of mud men in cal. that im sure could take care of this for you this a detailed project that requires pateince and a little knowledge maybe a little more than what we can give here
Old 07-05-03, 08:29 PM
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Thanks floorman, I think that within my knowledge it will be better to take off the ceramic tile and bring the height in an easier way like with plywood and backerboard.

Now, any suggestions on in which layer of subfloor the toilet bowl should seat. I would love to sit the toilet bowl on top of the new tile but I am worried that it will be too high to ensure a tight seal with the wax ring.

Any comments,

Thanks again


Old 07-06-03, 08:56 AM
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If it's not too much difference you can use a wax ring with a flange and a ring on top of that. You may need to raise the toilet flange itself not on the tile though
Old 07-10-03, 09:43 AM
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Thanks Daniel and floorman:

This is the new plan.

Take of the existing tile.

Bring up the height using the appropriate Plywood and backerboard. Underneath plywood I will lay a 6 mill moisture barrier.

Toilet bowl will sit on backerboard layer. It will probably be one inch higher than now.

New tile will be laid around the toilet bowl.

Seal everything and that is it.

Please comment on the plan.

Regards and thanks again.

Old 07-10-03, 04:55 PM
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I very strongly advise against setting your toilet on the backerboard and tiling around it. Set the toilet on the tile. If you don't trust wax rings (the thing least likely to go wrong of all the things in your house), then you can trust the flange extenders.
Old 07-10-03, 05:05 PM
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Dude! Your on your way to a disaster!!!

Floorman gave you the proper procedure, for a mud bed. The only recommended method for your circumstance.

I'm wondering if you could mail me the cash before you throw it down that toilet, your worried about the wax ring sealing on.

Plywood over concrete, even with a moisture barrier(then thrown in a bathroom installation into the mix) is asking for trouble. Even with the CBU.

Your going to need a plumber to extend the flange!

The toilet needs to sit on top of the tile. What happens if that toilet gets broke? You think your going to find the exact bottom on a toilet?

Why do it twice, when you could do it right the first time? Oh ya, it isn't in your budget. Is it in your budget to do it again, only the next time with a mudbed, and without cutting corners to save a buck now? Pay me now, or pay me big time later. So now you will pay 3 times what it should have originally cost, after it fails. Sounds like a bargain!
Old 07-10-03, 10:28 PM
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Thanks John and CDW:

Toilet bowl to sit on the tile, I got it.

Wax Rings I trust but I think that the flange will have to be extended.

Mudbed will be hire out I got it too. I will not call a plumber to extend the flange, what is the point for this website then?

I will post all the headaches and screwups along the way so it might help somebody else.

I might recommend calling a plumber after I'm done.

Thanks again guys


Old 07-11-03, 06:00 AM
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Originally posted by Urip
what is the point for this website then?

I didn't say you couldn't do it.
We are here to keep you from throwing money down the toilet. As you were headed that way.

We are here so you have lasting enjoyment from your flooring projects. Not constant headaches and repairs.
It sounded like you were being fed information from a Home Depot employee. They lead so many people to disaster.

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