Uncoupling Membrane for Penny Tile

[pilotman]

Hello,

I am doing a tearout and installation of a new bathroom. I have 2x10 joists and 3/4 plywood currently. I have also reinforced the subfloor with sister joists and blocking (easy access from the basement) to stiffen everything up. There is virtually no flex.

My wife picked out 12x12 sheets of penny tile.

In doing research, I noticed that I *cannot* use Schulter Ditra because it is not recommended for tiles smaller than 2".

According to my research here, it seems some people use either Noble TS or Greenskin.

So, what is the best approach?

1) apply Noble TS or Greenskin over plywood, then tile over that? Do you just apply the Noble TS or Greenskin to plywood with thinset?

2) or just use cement backerboard, and this skips the need for an uncoupling membrane like Noble TS or Greenskin?

I can basically proceed however I wanted, there are no real subfloor height issues and the bathroom floor is very small, about 5x6 feet.

What is easiest/best method to get subfloor suitable for penny tile in these circumstances?

Thanks!

[Lazarus]

I have used Greenskin in the past and like it.

[cx]

Welcome, Brandon.

Originally Posted by Brandon

I have 2x10 joists and 3/4 plywood currently.

Doesn't tell us much without we know at least the unsupported span of the joists and the spacing of them.

1. The NobleSeal TS is applied directly over your plywood subfloor using thinset mortar. Greenskin is a very thin peel-and-stick membrane with much less background. Given the choice, I'd certainly go with the Noble product.

2. Neither the NobleSeal TS nor the Greenskin is an Uncoupling membrane and there is never actually a need for an uncoupling membrane. A CBU would be a suitable tile substrate in your application if properly installed.

My opinion; worth price charged.

[Tiger Mountain Tile Inc]

Cement board is the cheapest. It's not the lightest or the easiest to cut but that's what I use when tile is going over wood and is too small for uncoupling membranes.

Otherwise, Noble TS is a good product. Yes, you can install with thinset.

I don't know if Greenskin still exists anymore. Last I heard, was about a bunch of delaminating issues but that was several years ago.

[pilotman]

Thank you. And the joists are 16 OC and I already
sistered them and added blocking, so there is very little deflection

I'll probably just use CBU then.

Should I waterproof it with hydroban or similar or just buy the hardiebacker that is already waterproof?

This is for the floor outside the tub so definitely not a shower floor.

Thanks!

[jadnashua]

Neither the industry guidelines nor code requires waterproofing the floor of a bathroom unless you regularly flood it or it's part of a wet room...so, while you can do that if you want, regular cbu would be just fine. In a typical bathroom, if you were to flood it, it would flow out the doorway or maybe down around the toilet flange edges, or into the walls, or under the tub.

[Tool Guy - Kg]

Welcome to the forum, Brandon.

Keep in mind that these penny rounds will follow every little wave or bump in the substrate they are installed over. You want to start with a very flat substrate or you will be disappointed in the finished surface. You’ll have your hands full enough just placing the sheets perfectly so that the grout lines at the edges aren’t noticeable. Speaking of grout joints, you’ll be doing yourself a huge favor to pick a grout color that blends, rather than contrasts, so imperfections in spacing are more muted. But I’m straying away from your main question of your substrate…

Use cement board if you must. But keep in mind that cement board isn’t exactly flat. If you use it, prep it carefully do that you start with the flattest possible surface.

Rather than cement board under these penny rounds, I’d prefer prepping your plywood subfloor flat, then installing something like NobleSeal over it. This is an easier way to start with a very flat surface to tile over. Food for thought.

[jadnashua]

CBU will follow the floor, so if it isn't flat, while the CBU might buffer the imperfections some, it will follow them for the most part.

[pilotman]

thanks, I appreciate the advice.

Frankly I'd like to avoid using cement backerboard if I can.

I'm using Laticrete Hydroban Board for the shower, hate cement board.

i'll probably give the Noble TS product a go, it sounds a lot easier and cleaner than cement backerboard.

so I just get my subfloor strong and flat as possible, and then attach the Noble TS with thinset (or their Noble EXT adhesive) and I should be good?

I'm thinking of using Ardex WA epoxy because I understand that you can use it as thinset for the penny tile plus grout, all in one.

[Tiger Mountain Tile Inc]

You can buy a waterproof foam backer board in 1/4 inch thickness and install it on a floor instead of cement board. It's more expensive but it sounds like that might be a suitable solution in this case.

I'm not sure if Laticrete has 1/4 inch in their Hydroban board but they might. Otherwise, you can find it in other brands.

For epoxy grout, I think I'd set these penny tile in thinset then grout with an epoxy after. You're going to use up a good amount of epoxy on penny tiles anyway and that stuff isn't cheap.