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Don’t let your tile accent strip look like this

How to install tile of different thicknesses flush, flat, and even with each other

glass mosaic accent tile
Mosaic tile installed as an accent


Getting your mosaic and glass tile accent strips to be flush and flat with the surrounding tile can be difficult unless you know a trick for it. Here’s a technique for building up the thinner decorative tile so that it’s even with the thicker tile without creating a huge mess of thinset oozing out of the grout joints.


But first you might want to try this

Roger has a technique posted on his site that accomplishes the same thing, but in a different way. The method that he showcases is easier, but it doesn’t work in every situation. I encourage you to check out his post Setting different thicknesses of tile for inserts.


See my post on the Proper Placement Height of a Tile Accent in a Shower


tile spacers cut same size accent tile
The tiles to each side were cut out of scrap and are the exact size as the accent tile and are used as spacers

1. First install the field tile with spacers

I cut spacers out of scrap tile that are the exact same size as the glass accents, so I can install the wall tile first. Once the wall tile is dry the spacers are pulled out. I put the plastic blue tile spacers in where the grout joints will go on the top and bottom. (See photos to right)

2. Create your very own custom tile tool

Get yourself a plastic putty knife that is wider than the decorative accent band and cut it so that it will trowel slightly deeper (no more than 1/16th of an inch deeper) than your mosaic accent tile.

3. Make the channel the correct depth

tile spacers in accent channel
The spacers are used to space the accent channel

Tape off both sides of the accent channel and fill it with thinset. Use your putty knife to trowel the mortar to the right depth paying special attention to the corners and the ends. Make sure to run it on both the top and bottom of the channel. Keep clean water and a sponge to make sure things stay clean.

4. Install the mosaic or glass accent band

Take your same putty knife and turn it into a notch trowel.  I used an 1/8″ x 1/8″ notch trowel as a template, marked out the notches with a sharpie, and cut the notches with my tile saw.

Then trowel more thinset into the channel using your plastic notch trowel and install the mosaic tile. I use a grout float to beat it into place. Use spacers to center it in the channel.

putty knife cut into trowel
Create a trowel out of a plastic putty knife


There’s more than one method to get your mosaic accent band flush with the rest of the wall tile. Although this method is time consuming I feel it creates the nicest finished product.

Please let me know if you have any questions.


thinset in tile accent channel
Use the trowel to get the thinset mortar to the correct depth







mosaic accent tile being installed
Install the mosaic in the channel and use a grout float to press it in. Then install spacers to make it even and straighten it out.
accent tile installed flat straight
mosaic accent installed flat and straight









notch trowel putty knife
A custom made notch trowel for installing the mosaic
crooked uneven accent tile
Using this technique will help prevent this.








  1. Thanks for posting this..I am a remodeling contractor and have always had difficulty in getting this done efficiently. I always ended up with a great looking job, but fighting the lippage and thinset was always frustrating. I should dope-slap myself for not finding your method sooner. If you’re interested I’ll keep you posted on my latest project – I’m actually not dreading going to the jobsite this morning after learning this.


  2. What I do is….lay mosaics face down on flat surface….next skim coat back of mosaic…..next day it’s 1 stiff piece. Mosaics are 100% flat. Then bond to wall with a few dabs of mortar.

  3. not a bad process….fill the area with thinset where the mosiac/listello/decorative tile is going be installed…take a piece of 1/4 plywood and make a screed stick….notch the screed stick to the thisckness of the mosiac and a a little for the thinset to be applied for installation….screed the area that you filled with your screed stick and let dry…after it has dried apply the thickness of thinset desired and then install your mosiac/listello or decorative tile. no matter how thick the bottom or top of the tile you installed is with a screed stick it will balance itself out as you make ur pass in the thinset….after installation of you mosiac it will lie flat and even with your wall tile.

  4. pete…when installing tile in a wet moist area such as a shower the industry standards is 95% or better of thinset coverage and contact to the substrate surface. dapping thinset is below industry standards…..spot setting tile in a shower is an old timers way….nothing but warranty problems with a greater chance to fail.

  5. How about building out mosaic area with Kerdi material and thinset

    • What I’ve shown here is simply one way of doing it. There are other ways and the way that you had mentioned is similar to the link that I posted in the beginning of the post that Roger has shown at his site.

  6. I’m trying to install a 4″ wide mosaic accent in a shower. The mosaic tiles are about 3/32 thinner than the base tiles. I want to try your method, but have a couple questions:
    1) when I fill the channel with thin set (step 3), can I let that dry, or partially set, before the next step?
    2) I’m concerned about the thin set sagging. Do you mix it “thicker” to prevent this?
    3) would it be OK to butter the back of the accent tiles in step 4, rather than using a notched trowel in the channel?

    • Hi Duane, I’ll answer the questions as they are numbered:

      1) Yes
      2) Yes. More peanut butter-y than say yogurt-y.
      3) No. The problem is that the thinset will show through. A lot of times I skip the notched trowel step and just put the mosaic in. I don’t even let the thinset dry. But if you’re worried about sag then it’s probably best to do it in 2 steps.

      Additionally, you can adjust the amount of thinset in the channel by varying the angle of the plastic knife. For instance if you hold it straight out at a 90 degree angle you’ll have less thinset in the channel than if you held it at an angle.

      So you might be able to do it that way using the same plastic putty knife for both steps and without making notches in it.

  7. My problem is the other way around. I have marble accent tiles that I want to use that are about 1/16″ thicker than the surrounding wall tiles that I have already purchased. Is there a solution for this?

    • Assuming that none of the tile is installed yet, I think you’ll find that once the bigger wall tile are installed that this problem will go away. The mosaics shouldn’t stick out past at that point.

  8. AS a long-time general home improvement guy, this post has been truly helpful. I do a fair bit of tiling, but his definitely helps to raise my game. Thanks!

  9. Ok, I am a first timer trying to tile an outdoor patio table top. We have never tiled anything. I looked all over Pinterest for inspiration and have been googling how to tile, what to use, etc. I am using an old electrical wire wooden spool for my table (60″ round). My husband wrapped a piece of steel metal around the edge of the spool leaving about 1/4″ above the top. I am laying a Mosaic pattern on top with 4-18″ square porcelain tiles with 4″ tiles around the outside and filling in between the large tiles and the outside tiles with 2″ tiles in between. I wanted to cover the top with backerboard but my husband refuses. He thinks it will be fine to just tile on top of the wood. I said we should at least lay a thin set of the mortar first to kind of even out the boards (not flat and have gaps) – let it dry overnight and then do our regular mortar to set the tiles on. Will that work for this purpose of trying to get by as cheap as we can since it won’t have a lot of weight on it like a floor? Also the 3 tiles are different thicknesses. And since it a random pattern would be hard to put something behind each one to build up the not so thick ones. Is there a way to place them on the mortar and then lay a board or something over them after placing them to kind of push them in to the mortar the same depth?

    • Interesting question. I don’t think it’s advisable to tile over the top of a wooden spool. I don’t think it’s going to last. The absolute best way to go about it would be to use a foam board like Wedi board between the tile and the wooden table top. However, foam board is a bit of a specialty product and isn’t cheap. So my next suggestion would be to use cement board or hardibacker board.

      With the varying sizes of the tile I think if you can install them upside down that would be the best and flattest. In other words arrange the tiles upside down and adhere the backerboard to them. Let it dry and pick it up and flip the backerboard over and install on the spool. Depending on how much difference there is between the tile thickness and how much thinset you put down you may find that some of them don’t stick.

      So with cement board you are supposed to screw it down as well as thinset it down. If you adhere the tiles before hand then you wouldn’t be able to screw it to the spool top. But if you use a high quality thinset then you may be able to get away with not screwing it in this situation.

  10. I’m wanting to change the stripe on my bathroom tile without using paint. Is there a product out there that you can stick on over top of ithe stripe. It would have to be very thin so it doesn’t stick out and look like it’s part of the tile.

  11. I have recently cut a strip of Schlueter Deidre to raise my mosaic deco an eighth of an inch. I found this to be the quickest easiest and most precise way to make it flush with the adjacent field tile . My field tile was half inch porcelain .

  12. We hired our contractor to tile our shower with epoxy grout; however I just found out they are planning to use Fusion Pro Grout. I read a lot of terrible reviews about this grout and understand that it is not epoxy grout. Several reviews said it could not be used in shower pans and that water will erode away the grout. Is this true, or is the erodability a function of poor installation? If installed properly, will this grout be stain resistant, water resistant, and hard and durable for the long term?

  13. If you hired the contractor and specified epoxy then you should get epoxy grout. Epoxy and Fusion aren’t the same thing. Epoxy is a stronger and more durable grout.

    I’ve used Fusion several times going back to 2013. I haven’t experienced any problems with the grout and have had good success with it. I have heard of the shower pan issues but don’t know what the cause is or if it’s even more than rumors. For the time being I am holding off on using it on shower projects until there’s more clarity.

  14. Are you suppose to let the thinset dry between step 3 and step 4?

  15. i am installing a glass mosaic tile, paper front,brick layout in a channel between 1/4 (plus thinset) tiles. How much thinset should there be between thes glass tiles and backer board once installed, what size trowel should I use. My last time trying to install squeezed thinset out too much,created a mess, and therefore took the tiles down.


    • You might have to experiment a little. With glass you want enough thinset behind it for proper coverage and also because you’ll see if there isn’t enough thinset through the glass. But, like you said, if there’s too much on there it will come through the grout joints and make a big mess.

  16. Hownin the workd can you have confisence that you are building up the thinset just the right amount, and uniformly over a flat surface? Using just a plastic trowel and holding at an angle and just eye-balling it? Really? What am I missing?

    • It works. Use the accent tile to set the notch on the plastic trowel. You can hold a test piece of the accent in the channel to make sure you have the right depth.

  17. I think it is important to consider the depth of the grooves in a mosaic panel so that the walls of wherever they are installed are relatively smooth and even. My wife and I are thinking about renovating our kitchen and have been considering getting some mosaic designs for above the sink. I appreciate the design tips, I’ll have to consider getting glass if we ever go through with remodel.

  18. I am installing a 4″ row of 5/8″ mosaic accent tile in my shower. I have installed the 13 x 13 inch thick porcelain floor tiles on the walls up to the point where the mosaic tiles will go, having started the job with ledger boards. I don’t have the tiles above the mosaics in yet. I need to back up the mosaic tiles and like your method, but without installing the tile above them, can’t see it working right. Since the porcelain tiles are heavy would I have to use ledger boards again above the mosaic location to make the method work, the install the mosaics?

    • Yes! You can see in the photos above that I made spacers out of tile. You can use a ledger board if that’s what you prefer although you have to be careful to keep the spacing consistent all the way around.

      • I picked up some Ditra that seems the perfect thickness to put in behind the mosaic tiles to get level with the wall tiles. If I were to install the Ditra and mosaics in thinset first and then add on my top row of 13 x 13 inch wall tiles after they are cured, do you forsee any issues with spacers on the mosaics to mount the tiles, assuming the mosaics are in straight.

        • You can try it but I think it’s going to be a bit challenging because when you go to wedge the top 13×13 the only place to wedge off of is the small mosaic tiles. I think it could break some of these loose. However, if you do try it then I recommend installing the Ditra backward with the mosaic on the fleece side.

          • Jim,

            I followed your lead and used spacer blocks to set the upper row of wall tiles adjacent to the mosaic tile accent band area. I ended up cutting the exact height on my wooden spacers that I needed using a miter saw with a stop block. It worked great.

            So when you screeded on thinset for the mosaics in step 3 with a flat trowel, did you allow that to dry fully? Then in step 4 add more thinset and trowel with your improvised notched trowel? Would a normal 1/8″ trowel work just the same if the initial layer was fully set?
            Thanks for your help.

          • Yes, in the blog post above I did allow it to dry then used my homemade notch trowel. Since then, I’ve evolved into not letting it dry and just doing everything in one step although sometimes the depth of the channel doesn’t allow for that. It can be too deep and the thinset will need to dry first.

            But you can use a 1/8 inch notch trowel as long as it will fit in the groove. Oftentimes, they are too wide to fit in the channel.

  19. Great Article…. Wish I had read some of these comments before attempting to lay a decorative 36×36″ in my Foyer… This was my search “how thick must thinset be to adhere” The reason for that search is I was wondering how thick does the thinset need to be to have a good stick/foundation. I deduce 1/8″ since that is the smallest trowel I’ve seen. The reason for a thin application is due to the tiles that meet-up to my mosaic are a bit lower than desired (moved the mosaic planned) . Hence me thinking Mastic and off down the rabbit hole on the Net. Great tips and tricks, I will add that tid-bit about thin set on the back to have a ‘stiffer’ mat to work with.

    Thanks again,

    • You may also want to experiment with mounting them on a foam panel first. You can get foam board in 1/8 or 1/4 inch thicknesses. That may solve the problem that you are having.

  20. Thank you for your thorough post. Very helpful.

  21. Hi, if the contractor installed the glass and stone mosaic wall tiles in my bathroom as a decorative stripe and they are all uneven, not flat, I have the right to ask him to redo them, or correct them, right? This is my first time ever remodeling my bathroom, but to me it seems wrong if they want to give it to me like this…. Please advise, thank you for your feedback. And I am not talking about a millimeter here and there, larger, 5-6 millimeter depth, mosaics sticking out, etc etc. Not flat or even with the surrounding tiles at all…. Please tell me what you think….

    • Yes. Unless the look of it is supposed to be uneven which it sounds like this is not the case. So if it looks uneven with lippage then it should be redone at the contractor’s expense.

  22. Good heavens! Thank you! I thought I was going to lose my mind this past week. Never could get it flat. Now I know what to do!

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