Tiling over tile - new cement board?


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Old 03-18-17, 12:32 PM
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Tiling over tile - new cement board?

I am remodeling my master bath. I started to remove the 12x12 ceramic tiles only to find 2x2 ceramic tiles underneath them. I had these 2x2 tiles in the guest bath when I remodeled and they were a nightmare to get up.

I know I don't want to lay new tile (most likely porcelain) over the existing tile directly. My question is can I put a sheet of cement board over the existing tile and use that as my base? I am talking floor only. Any downside to this? I could use 1/4" or 1/2" and the height won't be an issue. I would screw the cement board down pre-drilling through the grout of the old tile and into the plywood subfloor.
 
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Old 03-18-17, 12:38 PM
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What type underlayment do the 2x2's sit on? If it is cbu, then take it all up in sheets. Not sure why taking the 2x2's will be such a bear. I would not recommend what you are planning. You won't be able to ensure you are drilling in the grout line, you will bust up tile inadvertently and make laying the cbu a nightmare.
 
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Old 03-18-17, 12:53 PM
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It was a nightmare because the thinset/adhesive were strong and they were coming up 1 tile or even part of a tile at a time. Given there were hundreds, it was time consuming. I am pretty sure it is on plywood, not CB but I could be remembering incorrectly. If I had a rotary hammer, I'm sure it would be easier.

In the other bath, the wall tiles were coming off with pieces of the cement board. I just ripped it all out and replaced the cement board.
 
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Old 03-18-17, 01:28 PM
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I cant imagine attempting to tile over a layer of tile, let alone 2 layers of existing tile without having some serious installation issues.

There must be around 3" of material on the floor, how would you even make the transition to any other floor?

I will admit I've only torn up a couple of tile floors but nothing a pry bar and chisel could not remove.
 
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Old 03-18-17, 01:38 PM
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It wouldn't be 3" of material. I would be removing the top layer of tile and putting CB on the first layer. It would be 1" maybe.
 
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Old 03-18-17, 01:41 PM
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I would suggest you head to the nearest Harbor Freight and get yourself a rotary hammer and SDS chisel. You can usually find coupons online or at the checkout. You should know that you need to tear it ALL off. Not just one layer.
 
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Old 03-18-17, 08:51 PM
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Yes, a demo hammer and a tile bit will make the job easier and more managable. Trying to get them out with a hammer and chisel would be a daunting task. Take both the tile and the cement mud bed out and let us know what you are left with. Most likely will need to add a layer of ply and then cement board.
 
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Old 03-19-17, 03:47 AM
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a hammer and chisel would be a daunting task
Not really, tile/CB/Mortar are not strong in shear, get between the layers they just pop off, getting down initially is a bit of work.

Good thing about doing it manual, you cay use a shop vac at same time and the entire job, and house, stay cleaner.
 
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Old 03-19-17, 10:11 AM
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Most likely the tile mosaic is set on top of a mud bed and not cement board. This will be reinforced with wire lath and not easy to get up manually. I've ripped out a ton of these and even with a demo hammer is is a task. After removal, normally a 3/4" ply layer and cement board plus tle will bring the level up so you don't have to reset the toilet flange.
 
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Old 03-19-17, 01:25 PM
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The lower tiles are on CB. They come off with a chisel/prybar and heavy hammer, but 1 or 1/2 tile at a time. How common is it to have to replace the CB after demo? I've only done a small area so it is hard to tell how it will look at the end.

I thought about renting a demo hammer, but have to imagine that would tear up the CB more. We are talking only about a 25 sq ft area so probably not worth the rental (the rest is shower and wall and just has the bigger tiles). I have a compressor and could get buy an air hammer too.

Edit: If inevitable the CB needs replacing, I may be able to rip pieces of that up with the tile on it saving time. There is plywood under the CB.
 
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Old 03-19-17, 02:38 PM
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That is what we have been saying. Rip the tile and cbu together. You can't effectively salvage used backer.
 
 

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