Setting different thicknesses of tile for inserts

by Roger

There are numerous really cool mosaics and liners which can be installed as an accent into your main field tile to add a unique touch to an otherwise standard tile installation. These are products such as glass and natural stone mosaics, individual painted tiles, or custom accents.

The biggest problem with these, however, is they are oftentimes not the same thickness as your main tile – they are usually thinner. This is especially true of most glass mosaics. I usually solve this problem with Schluter Ditra. Although I use ditra as my example in this post, you can also use regular 1/4″ backerboard if your inserts are significantly thinner.

glass mosaic insert

Photo 1

See that glass (and metal) mosaic right there? (Photo 1 – You can click on it for a size larger than a small dog) It’s setting inside the main linear mosaics I’m installing on a backsplash. See how much thinner it is than the surrounding tile? That’s what we’re gonna fix. When you have your tile installed you want it all to be on the same flat plane without either tile sticking out (or sinking back). The best way to do this is to have an additional substrate behind your thinner tile to bump it out flush with the rest.

You want to cut your ditra about 1/16″ smaller than the overall size of your insert. You want to make sure you have enough support behind the insert, but you don’t want it larger. (Photo 2)

glass mosaic insert with ditra

Photo 2

glass mosaic insert with ditra

Photo 3

 

 

 

 

 

 

 

In Photo 3 you can see where I’ve flipped the ditra upside down so the fleece side is out. You want to install your insert onto the fleece side rather than the plastic, dovetailed side. this is much easier, especially with smaller tiles, and gives the insert more adhesion on the backside once installed. The thinset will ‘lock’ it to the wall doing it this way.

Photos 4 and 5 show how the ditra bumps it up to the same height as the field tile. If your insert is a LOT thinner, it may be better to use the 1/4″ backerboard, although you can double-up the ditra to make it thicker.

glass mosaic insert with ditra

Photo 4

glass mosaic insert with ditra

Photo 5

 

 

 

 

 

 

 

Once you get your ditra and inserts cut to size (cut all of them at once) get your thinset mixed up and cover the entire fleece side of the ditra inserts. Make sure the entire surface is covered, most mosaics are fairly small and any uncovered areas may lead to just one or two pieces not being adhered well. Spread it just like these here:

glass mosaic insert with ditra

Photo 6

glass mosaic insert with ditra

Photo 7

 

 

 

 

 

 

 

 

Then place your inserts onto the ditra and press down slightly – only slightly! Before you firmly press the inserts and the ditra together you want to flip them upside down. Doing this ensures that the face of your inserts, the shiny part that makes people go ‘ooooh, pretty’, is completely flat. Flipping them upside down, then pressing down firmly, will get the entire face totally flat and get a full bond onto the ditra. It is always best to use a flat surface on the back, squeezing them between the flat surface and the flat countertop or bench – whatever your wife lets you use. Like these:

glass mosaic insert with ditra

Photo 8

glass mosaic insert with ditra

Photo 9

 

 

 

 

 

 

Once you get them all installed to the ditra, flipped, and pressed down firmly to ensure a full bond – leave them alone! Give the thinset at least three hours to cure and get a grab, ideally let them set overnight. Really, leave them alone. Stop staring at them. Go have a beer Pepsi and have some dinner. We’ll get to them later.

glass mosaic insert with ditra

STOP STARING! GO AWAY...

Once the thinset is cured you can fill the dovetails with the flat side of your trowel, then comb on the thinset with the notched side and install them into your design. You can cut your main field tile with spaces large enough for your insert (don’t forget the measurement for the grout line around the mosaics). And tile away. When you’re finished you should have two different tiles, with different thicknesses, installed flush on the same plane. Like this here:

glass mosaic insert with ditra

Finished

This method works for backsplashes, shower walls, even tile floors. As long as you have good contact with the insert to the ditra, and good contact behind the ditra to the substrate, you should have a nice, flush tile installation which makes people go ‘ooooh, pretty’. Like these here:

glass mosaic insert with ditra

Ooooh, Pretty...

Porcelain backsplash tile installation with glass mosaic inserts in Fort Collins, Colorado

Ooooh, Pretty < See?

 

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Tim

I’m looking for advice &/or tips. I am installing tile in a new bathroom shower and have chosen to use different size tile. My tile is 18″ x 18″, 9″ x 12″ and one row of 2″ x 2″. Where I bought the tile told me I need to use a 1/2″ notch trowel for the 18″ tile and 1/4″ trowel for the 9 x 12. I have since noticed that the 18″ tile are thicker then the 9 x 12. Should I use a different trowel for the different size tile or just use the 1/2″ for both to make up for the thickness difference or use 2 different trowels and a backer?

Reply

Roger

Hi Tim,

You can use the 1/2″ for both and compensate for the thickness with thinset.

Reply

Marsha

I have a tile installer telling me that the mosaic that i have picked out are too thin (there is quite a difference between the wall and decorative tile). He is suggesting i find something thicker, but after reading this I dont see an issue. Sounds like on the strip that i want the thinner tile used he just needs to build up with some type of a backer. He said that the thin mosaics that i have picked are tradionally meant to go over existing tiles…. help…….

Reply

Roger

Hi Marsha,

That’s bullshit, no tile is manufactured to go over another tile. It can be done, perhaps you need to find a contractor who knows what he’s doing. I do it (literally) every week. :D

Reply

Joe

I saw you mention not using Ditra on your entire shower wall as the dovetails can retain water…

Is it acceptable to use Ditra in a 12″ strip from floor to ceiling in my shower, waffle/dovetail side to the wall, fleece side to tile, with polymer modified thinset between the Ditra/Redgarded walls and then between the Ditra/Penny tile?

If it matters, it is a 12″x36″ strip from the floor up, then a niche that’s already tiled, then a 12″x24″ strip to the ceiling.

Thanks so much for your expertise.

Reply

Roger

Hi Joe,

Yes, that’s fine.

Reply

Joe

Hi Roger,

Great site! I’m thinking of using this method in my shower, where I have mostly 3/8″ thick tile (just installed) and will be installing a 12″ wide accent strip of 1/4″ thick penny tile going from the floor to the ceiling (ready to install). As it’s a larger area of the penny tile and not small accent pieces, what would you recommend? Install the Ditra to the wall first, let it cure, then install the penny tile to the Ditra? If so, would the dovetailed side go towards the wall or tile? Thanks!

Reply

Joe

Just saw the “previous comments” link and found the answer a page back. Thanks!

Reply

Roger

Hi Joe,

Install the ditra first waffle side toward the wall, then install your mosaic. You don’t need to wait for it to cure.

Reply

Ed

As a follow-up to my previous question…2 things. 1) I checked websites and found that Ditra comes in 1/8 thickness and 2) I measured the height diff between main field tiles and mosaic inserts, and it’s only a 1/16 thickness diff. Maybe i should just try and build up extra thinset in areas left for mosaic tiles, after laying and drying main field tiles?

Reply

Roger

If it’s only 1/16″ then thinset is the better option.

Reply

Ed

Roger…thanks for the great idea. I am just about to start on a bathroom floor, tiling for the very first time! I noticed a difference between the main 12×12 field porcelain tiles and the mosaic ceramic tiles. Looks to be about a 1/8 inch diff in thickness, but does Ditra come in such a thin size? If not, what else could i use?

Thanks again,
Ed

Reply

Roger

Hi Ed,

Ditra works just fine for 1/8″ (That’s how thick it is).

Reply

Mike Greenfield

I currently have a tub with three rows of 4 1/2″ square thin tiles above the tub and am having a shower installed. we would like to use 12″ square tiles above the rows currently there. The 12″ tiles are thicker than the 4 1/2″ tiles. The installer says that he can grout between the two to form a transition between thicknesses. I would appreciate your comments on this.
Mike

Reply

Roger

Hey Mike,

I think it’ll look like shit. :D It will be more of a ramp than a transition. If the new tile were thinner than the existing it could be installed flush, but given what you have there’s really no way to make it look ‘normal’. Maybe a transition strip of mosaics or something between the two? It would at least not be as noticeable.

Reply

Dave

Thanks, Roger, for the great tip on this issue and for a truly helpful web site! I was contemplating the (probably disastrous) method of trying to build up a thick layer of thinset to accomplish an even plane of different thicknesses. Now I will be using one or two layers of the Kerdi fabric I used in the shower for my three inch wide mosaic accent band in my 18 x 18 shower wall tile field. Thanks again!

Reply

suz

Hi Roger I did the ditra and mosaic and have an issue with it. I used bostik modified thinset glued the mosaic to it. Let it set over night and it the thinset did not adhere to the ditra or to the tile. It loosened the glue that gel the mosaic to its netting and adhered to the netting but not the net side of the ditra. I know the thinset was Ok because where it spilled out onto my tarp its as hard as concrete. Do you have any idea what or where I went wrong? I used a 1/4 inch notch trowel on it. Thanks and thanks for the fan website. Ps any ideas now to salvage my mess since the mosaics are now pretty.much just loose tiles.

Reply

Roger

Hi Suz,

It may have been that you did not wiggle the mosaic into the thinset to get a good bond, but I believe it is the mosaic itself. On some of those they put WAY too much adhesive, and on some the adhesive is water soluble. Stupid, right? You do need to make sure to burn the thinset into the netting on the back of the ditra to get a good bond, but the mosaic should not have come off the netting due to the thinset. I don’t know how big your mosaic pieces are, but if they are still relatively in the right pattern you can turn them upside down, burn thinset onto the ditra, comb it then lay the ditra over the backside of the tiles and wiggle it around to get a bond.

Reply

Suz

Thanks Roger. I did wiggle them, there was thinset on the back of the tiles but it crumbled wherever the netting was. I believe that may have been the issue and there is some sort of slick piece of paper paper behind each glass piece. There were some tiles where I had cuts that had no netting or paper backing and the thinset stuck to those. I tried to redo a few of them today to see if it will work but what a pain. The tiles are 12×12 and I am cutting them into 3×10 pieces. I will check on them tomorrow. I found a forum that said some glass tiles need high polymer content thinset. I just used standard modified thinset.

Reply

Lou

HI ROGER,
Read all your books on design and tile tips ,looked at all the pictures too.I have a design question or problem.I want to use 12 x24 tile on floor and two walls horazonaly 4 ft. up. Then to tub surround to the ceiling. If i use the 33% rule and center at the tub how do the grout lines line up and if i line up with the floor, the opposite wall from the tub will not line up with the floor.one wall will have a free standing vanity covering most of that wall. It is 90 degrees from and next to the tub. 5×5 floor two 4×5 L shaped walls, then tub walls 3,5,3. Door and shower door on other wall. I also have a 2×6 hall way to enter the bath room and a toilet and closet on right of hall ,witch will all be tiled. Do I go vertical to center and balance tile or change size of tile. Small room 5×9, same problem for steam shower. I hope this all makes sense.

Question two. can ditra be cut to fill in small spaces and to save waste or do you need one full cut for each space. I have a toilet and closet area that can be filledin with left over from the bathroom with very little waste.

Reply

Roger

Hi Lou,

When doing an offset like that with perpendicular walls the grout lines will rarely line up through the entire installation, you always have walls which will butt the long side against the short side. Just lay out each wall so the grout lines DO NOT line up, and get them as close to the offset you’re using, in this case 33%, as you can. As long as the grout lines do not match, or are not closer than three inches or so to one another, it looks completely normal.

Yes, you can patch ditra in with small pieces, it works just as well.

Reply

Patrick

Roger

I have just removed all the slate tile from the stoop outside our front door and am about to retile the stoop using Kerdi and Ditra. We live in Canada, so the stoop is subject to freezing in the winter months. I was thinking, possibly dangerously, that I could instal the Ditra with the flock on the top. That way, no water will collect in the little squares with the bevelled sides and I should minimize problems with freezing and expansion of water collecting in those little upside-down plastic hats on Ditra when it is installed with the flock down. This is how the Ditra-Drain product works, but the hats have been replace with bumps. Please fill me in the problems associated with installing Ditra upside down. Thank you very much.

Patrick Cowan

Reply

Roger

Hi Patrick,

You won’t get a complete bond to the substrate with the waffles as you would with the fleece, and the bottom has cavities as well under the fleece, just in opposite places. Your best bet is to install the ditra right side up, then cover that with kerdi. That will give you the bond you need as well as waterproofing the surface.

Reply

Patrick

Thank you very much, Roger. This sounds like a wonderful solution which will make installing the Kerdi easier. Cheers!
Patrick Cowan

Reply

Julie

Hi Roger,

Love your website. Thanks for taking the time to do it! Hey,
I’m getting ready to tile my shower and I’m using 6×24 porcelain tiles that are 3/8″ thick with small glass mosaic strips that are not as thick. So, I like the idea of using Ditra as a backer for those strips. I even have some leftover from a flooring project! The problem is that the glass tile on top of the Ditra makes it a little thicker than the porcelain. Can that be dealt with by varying the thickness of the thinset when I’m installing the tiles or am I asking for trouble with that kind of thinking? Is there another material I could use as a backer? Thanks for your help!

Reply

Roger

Hi Julie,

You can use any substrate that is rated for use in wet areas. I’ve used 1/4″ durock, 3/16″ kerdi-board or even kerdi. With kerdi it doesn’t add thickness, but you can build up the thickness of the thinset beneath it without it coming through the mosaics.

Reply

Mark Knize

Hi Roger,

I want to use Ditra to make glass tiles the same thickness as the rest of my tiles. I will be using 2 small tiles to form 1″ x 2″ tile inserts for our pattern. I see that latex modified thin-set should be used on my glass tiles, but unmodified thin-set should be used with Ditra. Which type of thin-set should I use?

Reply

Roger

Hi Mark,

Modified.

Reply

Mark

Hi Roger,

I have a Lowe’s near me that sells a couple Mapei products. Should I use Mapei’s white porcelain tile mortar (yes, its modified) to install the glass inserts to the Ditra?

Also, can I use the same modified thin set to install the inserts onto drywall? The main tiles are ceramic 6″ x 6″.

One last question- in your experience, do I really have to apply Mapei’s “multipurpose acrylic latex prime” on my walls before applying the thin set?

Thanks for the advise,
Mark

Reply

Roger

Hi Mark,

Yes, yes, and no, never.

That was easy, thanks. :D

Reply

Mark

Hi Roger,

I have finished my kitchen backsplash project! I want to upload pictures to show off my work, but I can’t get them uploaded. When I click upload, I end up on another page that asks if I am sure I want to do this, but there is not a button to confirm.

Reply

Roger
Lorann

Thanks for the great idea of putting ditra on the back of the thinner mosaic so they finish at the same level thickness. My question is – with the ditra adhered to the mosaic, can you use the wet saw to cut all of it together to the needed size as you are installing? I’m planning on adhering the ditra to all the mosaic pieces at once so they have plenty of time to dry (I got that memo:) ). I think if I try to pre-cut around the outlets for the mosaic before adhering the ditra, as I go along installing the cut ones I thought were perfect before everything else was installed, then won’t fit so well.
Thanks for your assistance!

Reply

Roger

Hi Lorann,

Yes you can cut it on the saw after it’s bonded to the ditra.

Reply

Mark Knize

Thanks Roger.

I found a place to order Ditra by the foot. When I told him I only wanted 4 square feet he asked “What are you trying to accomplish”? When I described your tile insert trick, his only replay was “that’s a good idea”. Your tips even impress other pros!

Reply

Josh

Roger,

I notice you say here that you can use 1/4″ backer to fix this as well. I think this is the way I need to go. I used hardi as the original backer. I was thinking of using 1/4″ Duroc to ‘fill in’ the difference between 1/2″ travertine and 3/8″ glass accent. If so, would I just thinset that Duroc to the hardi with something like Versabond? I am thinking I will tile up the wall to this spot, then set in the duroc, let cure for a day, then add accent and finish tiling up. Maybe just leave a space for accent as I tile up. Either way, is thinset the way to set the duroc to the hardi?

Reply

Roger

Hi Josh,

Yes, just thinset to bond the filler strip to the substrate.

Reply

Andy

Hi Roger,
Thanks to your very helpful website, I decided to add a shower to my basement remodel. I used Kerdi to waterproof and have begun tiling. Instead of jackhammering up the concrete for the drain, I am using a macerating toilet system capable of handling a shower as well. Due to this, the shower floor is a bit higher than usual. The vertical side of the curb is about 10″ and unfortunately not fully square. After tiling the top of the curb with bulldoze tile and keeping the center grout line straight, the bulldoze tile I used has an over hang that goes from about 3/8″ on one side (perfect so the face tiles will be nice and flush with the bullnose) to about 3/4″ on the other side. Can I use a layer or two of Ditra to build up the area so all face tiles are flush? Sorry if my description is confusing!

Reply

Roger

Hi Andy,

Yes, you can use kerdi, ditra, backerboard, nearly any proper tile substrate can be used to build it out where you need it.

Reply

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