New tile in Kitchen & hallway [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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04-11-2010, 11:59 AM
It's been a long time since I've been here.

I've seen similar posts but wanted to make sure I understand what I've read.

I tore up old kitchen tile and the 19/32 underlayment that it was installed on, that leaves me with a subfloor of 19/32 plywood. Two additional piece of info. I've got cabinets installed on top of the first lay of plywood and I've go hard wood that the original tile sat about 1/8" above and I lived with that for 10 years so I'm not opposed to the same arrangement.

Does it make sense to just lay a new layer of 19/32 and install the tile directly on that? I can't figure out how to add adequate sub-floor , backer board or ditra without adding height.

The joists are 9.25”, 16” on center (a couple that are 10” on center) with a span of 11 feet.

I've seen it said to rip out the sub floor and install a 3/4" subfloor and 1/4" backer board, but if I don't have to do that I don’t' want to due to the expense and effort.

If I install straight on to the plywood what type of thinnest or additive should I use.


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04-12-2010, 04:53 AM
Mike, tile on plywood applications have been around a long time, but they do require everything from the joists up to be exactly correct. I don't recommend it to DIYers, expecially when there are better ways to do it.

Assuming your current nominal 5/8" subfloor is in good shape (no rot or major demolition damage), I'd add a layer of 3/8" plywood (1/2" would be better), then either Ditra or Noble's membrane, then the tiles. Your floor will be closer to even with the adjoining hardwood. However, should the tile be higher, you can install a tapered wooden threshold strip (finsihed to match the hardwood) to make the transition less obvious.

04-12-2010, 08:47 PM
Thanks BB, how thick is installed ditra or noble? 1/8"?

My biggest issue is that I have cabinets sitting on top of the current 19/32" underlayment. I've got counter tops that I can't move, and I don't want to replace, does it make sense to use 3/8" plywood and a 1/4'' backer-board or to replace the with 19/32" plywood and tile on top of that?

Thanks again for any input

04-13-2010, 05:02 AM
Ditra is a bit over 1/8" installed, Noble is about 1/16".

Were it my kitchen, I'd install 3/8" plywood and Ditra. Leave the cabinets where they are, and deal with the loss of toe-kick space and transitions to the other rooms as best I could. Doing it your way doesn't save any height, and is riskier because your installation depends more heavily on the previous subfloor, which you don't know how was installed.

04-25-2010, 08:34 PM
Thanks for the reply BB. Got side tracked for a bit with work and the better half thinking she may want hardwood. That's settled and back to tile.

She wants the use 20" ceramic tiles and have them layed diagonally, any thought about using that big a tile and laying them like that? Is the subfloor good enough for the big tiles?



04-25-2010, 08:42 PM
Main thing with bigger tiles is the floor needs to be real flat, shoot for 1/8" in 10'. Fill in the low spots and sand the high spots. I'd also use a medium bed mortar like Laticrete 220 or Customs Marble & Granite to hold up those big things.

And I'd do as Bob suggested with the floor. Add 3/8 CC or better plywood & a tile friendly layer like Ditra, NobleSeal or 1/4" CBU.

04-28-2010, 05:57 PM
Thanks, I'm going to add a 1/2 layer of plywood glued & screwed and then either 1/4" CBU or Ditra (struggling with the added height or added cost) what spacing should I use for the screws. 6" around the perimeter? how about the rest?


04-28-2010, 07:00 PM
For the second layer of plywood, make sure no face grade is less than "C". So, AC, BC, or CC exterior glue plywood is OK. Install as indicated in the Ditra Handbook.

Link to the handbook over there ---> (it's Orange ;) )