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Trowel Size Matters

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1/4 inch v notch trowel size
Thinset combed with a 1/4 inch V-notch trowel to install Spider Web II Uncoupling Membrane

There are a lot of ways to screw up tile installation. You can have not enough mortar underneath the tile and it won’t stick. You can have too much and it comes up through the grout joints and makes a big mess! The tiles usually don’t tell you which trowel to use. So what’s the secret? Can you just buy one size of trowel and use it for everything?

Why all the different trowel sizes?

All a notch trowel does is provide a way to gauge how much thinset mortar you put down. You use the notch trowel and you can put down the same amount of mortar every time. What you want to do is put down enough mortar to get complete coverage underneath your tile.

Different tiles require different amounts of thinset. Also different underlayments require different amounts of mortar.quarter inch square notch v-notch trowel drawing

How are notch trowels measured?

Trowels are measured by the length, depth, and spacing of the notches, or teeth.

U-notch vs Square notch

I’ll be honest with you. I don’t really know the difference between the U notch and square notch trowels. It’s my understanding that there is a slight advantage to the U notch but I couldn’t tell you what it is. For the purposes of this post I consider square notch trowels and U notch trowels to be the same thing. If I list a 1/4″ x 1/4″ square notch and you purchase that size in a U notch then you’ll be ok.

Subway Tile Installation: Three Basic Tips

What is the best trowel size to use?

This depends on a lot of factors. What are you installing? Membranes, cement board, tile, or ? What size tile? Which membrane? Are you looking for the best trowel size for subway tile?

Below I have some general guidelines on which trowel size to use for different situations. This is just a guideline and you’ll have to try it out for yourself. What you want to achieve is the best possible coverage without getting too much mortar down.

Some of the factors involved in this are:  The size of the tile, the thickness of the tile, how big and deep the depressions on the back of the tile are, the consistency and type of thinset being used, and the surface that you are installing over.

different notch trowels
Different trowels for different applications. The 3/8″ square notch (2nd from right) is an uncommon size. A 1/4″ x 1/2″ is more common.

So start with this list below and you may have to fine tune things from here.

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1/8″ x 1/8″ notch trowel : Primarily a trowel to use for installing thinner membranes. After all, the Kerdi trowel is simply a 1/8×1/8″ notch trowel. Use it for installing kerdi, Valueseal, Hydroban sheet membrane, USG Durock shower membrane, etc. I can’t think of any tiles that you would want to use this trowel for.

1/4″ x 1/4 ”  (3/16) V-notch: I use this trowel and the Ditra trowel interchangeably. So this is a great trowel size for uncoupling membranes. Also I use this trowel for small thin glass tile mosaics. This may also be a nice trowel size for thin mosaics up to say 2×2 inches.

Which Thinset to use: Infographic

1/4″ x 1/4″ square notch: The most common trowel size in the tile industry. Use this trowel to install cement board on floors. Yes, you need thinset under your cement board and, no, construction adhesive isn’t the same thing. Also, use this trowel for installing Ditra Heat and Prodeso Heat membranes.

A great trowel for installing small ceramic tile such as 4.25 x 4.25, 6×6, and 3×6 subway tile is this 1/4 inch square notch trowel. This may also be a good trowel size for thicker (5/16+) mosaics.

1/4″ x 3/8″ square notch: Use this for 8×8’s and some of the 5/16″ thick 12×12 builder grade tile. Even some of the 4×12+ bigger subway-type tiles. Home Depot 4×16 Restore tile and such.

1/4″ x 1/2″ square notch: The 1/4″ x 1/2″ x 1/4″ square notch trowel is good for 12×12’s and 13×13’s maybe even up to 16×16’s no more than 3/8″ thick.

Euro notch trowel
A euro notch trowel from Rubi tools

1/2″ x 1/2″ square notch: I use this trowel size for any large format tiles. 15 inches and larger. Including 12×24’s, 16×16’s, 18×18’s, 12×12 marble and granite, and the popular 6×24 porcelain plank tiles.

3/4″ x 9/16″ U-notch: Anything bigger than what’s listed. 24×24’s maybe. Larger 24 inch natural stone. It’s rare that I use this trowel size.

More tips for installing wood look tile flooring

Smaller than 1/8 notch:  A trowel size smaller than a 1/8″ square notch trowel is usually for glues. While I occasionally use glues with some of my installations (Noblebond EXT for example) it’s not very common. The manufacturer of the glue will usually have a trowel recommendation for their product.

Euro notch and slant notch:   The Euro notch and slant notch trowels are trowels that are supposed to give more complete coverage. The idea is that they form notches in the mortar that are easier to collapse and leave less air pockets. However they really aren’t necessary to achieve proper coverage underneath your tiles.

The proper notch trowel size is important to a successful tile installation. This guide should get you started in the right direction. If there’s something that hasn’t been covered please let me know in the comments.

Reader Interactions

Comments

  1. Hi Jim!
    I was wondering if a 1/4 x 1/4 square notch trowel would be suitable for 7×20 tiles that I am laying down in my kitchen? I went to a tile shop and they told me it’d be okay. I am seeing many posts on 1/4 x 3/8 but no one really mentions the 7×20 tile I will be using. Appreciate the help!

    Reply

    • My post is simply a guideline. It’s up to the installer to determine the Trowel size that will give the best coverage.

      However for most tiles that size I would probably use a 1/4×1/2 of even a 1/2×1/2. You could probably use a 1/4×1/4 and use the notched side on both the floor and the back of the tile. This would kind of like be using a 1/4×1/2.

      Reply

      • I appreciate the input, I will take that into consideration as well. Great site, it has definitely helped me with my kitchen project. Keep up the great work, Thank you!

        Reply

        • I hate to say it but- it depends. The key is to get enough mortar under the tile. Will a 1/2 x 1/2 inch trowel do that? Possibly. But this is where floor flatness, mortar consistency, and tile warpage come into play.

          So I think the question to ask is: Am I getting enough mortar under my tile?

          I would check this frequently by picking up the tile and looking underneath it. You may find, for example, that the center’s aren’t getting enough mortar. You may find that you have to notch both the floor and the back of the tile. This may require two different size notch trowels. You may find that you have to notch the center of the tile and back butter (flat trowel) the ends. The trowel is just a tool to gauge the mortar.

          But I typically start with a 1/2 x 1/2 notch trowel and adjust from there.

          Reply

      • I have an 800 square-foot install of 12“ x 24“ plank tiles. The homeowner wants no grout lines. After the install it looks like crap because of all the crowning and not even joints. Now I understand why. This has been very informative and I thank you. Rick at qualified maintenance

        Reply

      • If they are thin, maybe 1/8 to 1/4 inch, then you’ll want a 1/8×1/8 or a 3/16 v-notch trowel. If they are thicker then a 1/4 inch square notch trowel would be more appropriate.

        Reply

  2. Hello, putting down large profile trav in a french pattern. I need very exact measurement at transition to the
    new hardwood floor…..
    I have to build up the subfloor of this tile entryway 2 1/4″. I will use a combo of plywood and hardie board. 1/2″ trowel thinset……should I estimate the thinset at 1/2″ or 1/4″.
    So in your estimation how much is the thinset compressed?
    Appr your thoughts

    Reply

    • I just ran into this situation and chose to bring the floor up with mud (drypack) rather than plywood/hardi. However, to answer the question I would say that a 1/2″x1/2″ notch trowel would leave less than 1/4 inch of adhesive. Probably more like 1/8-3/16. But you can always bring things up rather take away material. Your probably best leaving yourself about 1/4 inch and adding a bit more adhesive at the entry if necessary.

      Reply

      • People often forget to calculate based on the angle of the trowel. For example, a 1/2″ square notch is usually said to leave a 1/4″ bed once the half inch notches are all flattened out. However, since you comb the trowel at a 45 degree angle, you are effectively reducing the height of the notches to SIN(45)=.707, or 71% of their actual height. The 1/2″ square notch then leaves a .25*.707=.176″ bed; or just under 3/16″.

        Reply

        • Correct! Also, the metal teeth wear down in a non-uniform way. It’s basically impossible to come up with an exact measurement for mortar thickness for several reasons. But your measurements are probably the best answer so far.

          Reply

  3. Hi, and thanks for your service to us all!…..installing 48″x8″ planks……slab on grade floor, i tore out previous 12″x12″ ceramic..of course, previous thinset still VERY firmly on floor…but pretty darn level!…..do you reccomend a leveler type product to cover previous trowel lines?, or as long as its flat, im ok to go over?….. ive done tons of ceramic, but these are my 1st planks…(using in my kitchen)

    Reply

    • The proper way to do it would be to grind down the old thinset. Probably using dust-free grinding equipment (shop vac, dust shroud, etc). But if the thinset is down good then you can probably go right over it and have the tile bond to it. Obviously your floor height will be higher than before.

      Reply

  4. Nice article. I’m getting ready to start my first tile job in my small shower. Using 10×13 tiles. I plan to use a 1/4 x 3/8 trowel, or would a 1/4 x 1/2 work better? Also, what trowel can I use to apply thinset in the niche? Would it be ok to back butter the tiles instead of spreading it on the back/sides in the niche?

    Thank you for the help and great site!

    Reply

    • I would start with the 3/8 trowel and see how that works. I would think that would be the one to use. And it’s OK to back trowel the tile. A best practice would be to flat trowel the surface also. In this case that would be the niche.

      Reply

  5. Great article, I cant find a good answer to this though. I am about to start 3 tile projects all of which are on a slab. The first is Wood look tile (LFT) in my kitchen so i plan to use LFT Thinset and a 1/2 x 1/2 trowel. The Second and third are just a little out of my “norm” meaning i just have never laid Mosaic tiles on a floor application. My master bath we have 12×12 sheets of white marble mosiac tile each tile on the sheet is roughly 2″x2″, I was planning to use white thinset and a 1/4 x 1/4 Square notch. I am not sure that it will make a huge difference, but i was thinking to maybe use the 1/4 x 3/16 V notch instead? These tiles are roughly 1/4″ thick if that matters, Any input?
    Also, my quest bath we are using a 12×12 ceramic tile mosaic (the small circles that are about 3/4 to 1” each). these tiles are thinner, like 1/8” thickness. Originally i was going to go with the 1/4 x 1/4 square notch but there are too many options. Do you think ones better than another for these tiles on a floor application?

    Reply

    • The 1/4 inch square notch might work for the 2×2’s or it may be too much. If so, I would step down to the 1/4 inch V-notch. The same V-notch will probably work for the smaller round tiles.

      But you always have to make your own assessment.

      Reply

  7. installing 6 by 6 cheap Home Depot tile on shower wall, what size grout lines do you recommend? also, what size trowel would you use?

    Reply

    • The 6×6 tile have built in spacing lugs on the sides. So you can set them tightly together if you like but you’ll need to use an unsanded grout. You can space them further apart if you like also.

      A 1/4 x 1/4 square notch trowel would be the best for those.

      Reply

  8. When it comes to level systems using straps, caps and a plier, what is the best way to determine how many of each are needed with 6×48 tile? It’s a large job- 2400sqft
    The manufacturer didn’t list this size in the formula.

    Reply

    • I just looked at the download page for MLT systems and it looks like they figure 5/per tile (1 side only) for 16cm x 120cm plank tiles (6×48). That’s if I’m reading and converting things correctly. It’s Italian and in metric. Here’s a link to their download page and I downloaded the layout chart.

      The only wedges (or caps) that you will need are enough to keep busy for a day. They can be reused the next day after removal.

      mlt system layout calculator

      Reply

  10. I am applying a custom mosaic floor tile in my 1920’s home. The individual tiles are 3/8″ square and I am also using 1″ hexagon mosaic. What trowel notch size would you recommend for such a small tile size?

    Reply

    • It’s hard to give a definitive size but a 1/4 x 5/16 V notch towel would be a good one to try. Also a 1/8 x 1/8 square notch may work for the smaller tile.

      You want as much thinset as possible under the tiles without the mortar coming up through the grout joints.

      Reply

  11. I will be installing 7″ x 71″ ceramic plank tile on walls and a ceiling in a commercial setting. Trowel size is detrimental to the safety and quality of the finished product. I do not want too much thinset as it could keep the product from firmly staying in place while curing. Would love your recommendation for an appropriate trowel for this task.

    Thank you

    Reply

    • I understand what you are asking but understand that trowel size isn’t a detriment- the trowel is simply a gauge of how much mortar goes underneath the tile. The bottom line is that you want to achieve is 80% minimum mortar coverage underneath your tiles. How you get there is open for debate. I would be absolutely shocked if a 1/2″ x 1/2″ trowel will get you 80% coverage. I don’t think it will get close. So that means that you are going to be putting a lot of mortar under those tiles.

      Too much thinset isn’t your enemy. Too little is. I’ve installed plenty of tile on ceilings before. If you want to skimp on mortar then make sure that you wear a hard hat because too little will cause them too fall off and crash. A generous amount of mortar will allow them to suction onto the ceiling. The suction is what you want.

      Reply

  12. From what I understand the only advantage of using a U notch instead of a square notch is when you push your tile into the thinset, the U notch spreads from the bottom out and the square notch has a greater chance of folding over and trapping air. I still prefer square notch over U notch though.

    Reply

  13. Though enthusiastic, I have minimal previous tile experience, but plan to do quite a bit of it in a small house under construction right now. First up is a pad under a freestanding woodstove. It’s about 31″ x 40″. We’ve got concrete there now. The tile I’m planning to use is sandstone 12 x 12, 3/8″ thick, smooth on both sides, with a border of 1 inch mosaic tile. I watched a very credible YouTube video (he’s a pro!) that said natural stone tile should be buttered smoothly on the back, in addition to the notched application of thinset on the floor, and coverage should be at least 95%. Does that sound reasonable to you? It sounds like you would recommend a 1/2″ square notched trowel?

    Reply

    • Yes. What the installer is referring to is called “back buttering” and it is a best practice.

      For a trial size, a 1/4×1/2 notch trowel would probably be perfect. You’ll run into some issues with the mosaic border, though.

      You might check out my post on shower accent strips for a way to install those. But do the big tiles first and save the border for last.

      Reply

      • It is either the best practice, or it isn’t. It can’t be “a” best practice, because that would suggest it is one of many best things. Only one thing can be best. Stop letting marketing folks mess with you.

        Other than that… 🙂

        Thanks for the tips on the accent strips. Good idea, there.

        Reply

        • “A best practice is a method or technique that has been generally accepted as superior to any alternatives because it produces results that are superior to those achieved by other means or because it has become a standard way of doing things, e.g., a standard way of complying with legal or ethical requirements.” ~Wikipedia [emphasis mine] https://en.wikipedia.org/wiki/Best_practice

          Reply

  15. Hi, I saw a similar comment and response to a guy installing 7×71” plank tile. I will be installing something similar in size, that being 8×68”. I didn’t quite understand your answer. You didn’t think he would achieve 80% coverage with the 1/2”x1/2”. For my application on a wall, would you recommend the 3/4”x 3/4”? How do you know when you have good coverage? Your tile will stay on it’s own while drying?

    Reply

    • The 80% coverage guideline is for dry areas but if it’s a wet area, like a shower wall, then the guideline moves up to 95%.

      So to achieve that would require at the very least a 1/2 inch notch trowel and probably more like a 3/4 inch and you still may not get there.

      You may have to notch the back of the tile in the middle in addition to the wall. The tile may not require a 1/2 inch notch- you may only need a 1/4 x 1/4 inch square notch. But the middle of the tile is where you’ll see the lightest amount of thinset.

      To check for coverage, simply pull the tile back up after installing it. You’ll have to guess the amount of coverage that is there but if you see thinset notch lines then you don’t have enough mortar under the tile.

      Reply

  16. What size trowel would you recommend for a 6″x36″ plank tile? Can’t tell if this one falls under the “larger than 15” for 1/2 square trowel or the “bigger than listed” 3/4.

    Reply

      • Thank you. What are the consequences of using too much mortar because the notch size is too large other than going through the stuff faster and paying more? Is it more important to not use too much with thinset like CBP flexbond vs medium-bed mortar like the large format tile stuff like CBP ProLite?

        Reply

        • Besides what you’ve mentioned, the consequences are that:

          1.you can exceed the limits of the mortar by it being too thick of an application. This is more of a danger with thin bed mortars than it is with medium (LFT) mortars.

          2. It makes for a messy installation as the mortar will come up through the grout joints.

          To much is probably preferable to too thin assuming you’re within the thickness limits.

          Reply

  17. If I get a trowel that’s a bit too big, like 3/4×3/4 instead of 1/2×1/2, can I compensate by holding it at a flatter angle as I cut the notches? I mean something like 30 degrees or less instad of 45 degrees.

    Reply

      • Could you please explain how the mix thickness would help? Seems like if I mixed it thinner I would get the same bead and the same coverage but there would be less actual mortar material behind the tile once it dried and the bond would be weaker.

        Reply

        • So one of the issues with having too much mortar is that it will come up through the grout joints and make a big mess. Also, it can work to not keep the tile high enough.

          By mixing the mortar thicker you can probably negate this result.

          On the other hand, if you find that your mortar thickness is plenty high you could mix the mortar thinner and maybe that helps counteract this issue. You may choose to do this if you are coming up on a higher section of a floor or if you need to meet up with a lower neighboring flooring such as hardwood.

          But, for the most part, you should just keep the mix consistent. A 3/4 inch notch trowel should do just fine for 12×24’s and larger.

          Reply

          • Typically, you’ll be OK if you simply flat trowel the back. Sometimes it makes sense to leave a little extra in the middle to compensate for the curvature of the tile.

    • Crossposting from the john bridge forum, sorry.

      I finally got to setting that floor and used a half-ellipse notch trowel that falls between 1/2×1/2 and 3/4×3/4. My problem was that tiles were floating on a thick layer of mortar, I had to press them into level and I think they ended up pitching and rolling on me. Since I’m not very good and under the gun from the mortar skinning over, it did not come out especially flat. Lots of oozing out of the joints but that’s less of a problem. Clips didn’t help much if at all. Sad thing is the floor was flat enough that when I laid the tile out without mortar they were flatter than the finished product. If that’s my starting point, would it be beneficial to use a smaller notch trowel so there’s less room for error? I’m considering ripping it all up and redoing everything (except it’s over ditra so it’s angle grinder then hammer and chisel a few inches at a time…).

      Reply

      • Sorry to hear about your experience but I would need to know what size the tile is that you are working with and if there’s a pattern then that’s relevant also. It’s unusual that they would go in worse than the dry-lay but it could be too much mortar or it could be the mortar consistency.

        Let me know the tile size and I’ll check back in later today.

        Reply

        • I may be exaggerating about the dry layout having been better, I didn’t examine it as closely as the set tile, but it was pretty flat. Flat enough that I thought it’d be just a matter of tweaking. It’s 36″x6″ tile laid with 33% overlap. Tile is rectified so the planks aren’t detectably bowed. The mortar thickness is around 3/16 or a bit more which is about what I expected but there’s a few spots where it may have built up to near a quarter inch. There were a few tiles that were way out of whack that I tore out but the rest are within a credit card’s thickness or just a bit over.

          Reply

          • With plank tiles, especially 36-inch, they are going to be tough to get flat. Even if you think the floor is flat you’ll find out that it isn’t flat enough.

            The best thing is to do one row at a time and place a level, or straight edge, across the top of each row. Any gaps between the tile and straight edge will need to be fixed prior to moving onto the next row. When you do move onto the next row you may find that the first row still wasn’t as flat as you thought. It can be tough. I still recommend using a leveling system even though they aren’t miracle devices.

            I have a hunch that using less mortar isn’t the answer. You may try to thicken the mortar slightly. It’s hard to describe but “peanut-buttery” probably is too thick although I guess it depends on the brand. Yogurt would definitely be too thin for large tiles. Milkshake-like?

            Pretty scientific terms, huh? 😉

  18. How do you estimate how thick a layer of mortar will be based on what trowel you’ll be using? I need to build the floor up to a specific level, the bottom of a cast iron toilet flange, and I know the thicknesses of all the materials except of course the mortar. I was thinking figure out the cross-section of the notches in the trowel per inch then multiply by sin(30 deg)=1/2 to account for the angle I’ll be holding it at. (so for a 1/4×1/4×1/4 square notch, it’s (0.25*0.25/(0.25+0.25))*1/2=1/16″) Sounds over-precise but I know it’s an estimate. Is there a better way?

    Reply

    • There really isn’t a reliable way of doing it. What further complicates the issue is the flatness of the floor, what size the tile is, and what the pattern is.

      For example, you may have a hump in the floor 2 feet away from the toilet flange. If you measure the area right near the flange you may calculate one thickness. However, because of the hump in the floor you may have to build the tile up higher than you anticipated.

      But I think your calculations would be extremely close for an ideal installation. You can always make adjustments as you go such as double notching (the floor and the tile) or holding the trowel at an even more extreme angle.

      But if it needs to be exactly precise, I think buying the trowel and field testing is going to be most accurate.

      Reply

  19. I am about to install ceramic wall.They are 3/8 thick subway tile 3 inches wide by 12 inches long.Would love to know which size trowel would be best. It is a kitchen backlash on drywall.Thanks

    Reply

  20. Hi! I have a 2.5 x 8″ tile for a backsplash. Do you think the 1/4 x 1/4 square notch will work, or should I move up to the 1/4 x 3/8″? Thank you!

    Reply

  21. We are installing 12″x12″ blocks of penny tile for our kitchen backsplash. Will a 3/16″ v notch trowel be ok or should we go with the 1/4″?

    Reply

    • The V-notch will probably be ok for those. If you’re getting thinset in the joints then I would down grade to an 1/8 x 1/8. But the V-notch is what I would guess would be best.

      Reply

  22. I am installing 1×2 inch split face carrara tiles in 1×1 sheets on a wall.no grout. Will 1/4 square ntvh trowel work best?

    Reply

    • That will probably do ok. It’s best to pull a sheet back off and see how well it’s covered. If it’s not covering well then it’s best to step up to a 1/4 x 3/8.

      Reply

  23. I’m going to install 8″x48″ plank tile. I also want to back butter the tile. What trial size should I use for the floor and what size for the tile?

    Reply

  24. For a shower wall with hardibacker covered in Kerdi, and installing 12×24 porcelain tile, would you recommend 1/2 x 1/2 trowel, or 1/4 x 3/8 trowel with back butter? I think 1/2 x 1/2 with backbutter may be overkill?

    Reply

    • A 1/2 x 1/2 or 1/4 x 1/2 notch trowel should be fine. 1/4 x 3/8 trowel would probably work, as well.

      No matter what trowel you use you want to make sure that the thinset coverage is good under the sill.

      Reply

  26. I’m about to install a mosaic marble backsplash in my kitchen. The wall is painted and the Flexbond rep told me I can just sand it to get good adhesion. So I bought flexbond, but now I am not sure what trowel size to use. In the Home Depot video using flexbond to install backsplash, they use a 1/4″ square notch for small marble mosaics. I thought it should be 3/16 V-Notch. The largest tile in the mosaic is 1.5″ by 7″.. I bought a 3/16 V notch but I can return it if it’s the wrong one.
    What towel size would you recommend?
    Their video also shows mixing grout powder and then it becomes a huge mess over the marble. Would the pre-mixed grout be a lot easier to apply than the mix yourself?
    The video is here:
    https://www.youtube.com/watch?time_continue=207&v=2lRBvYsono4
    The grouting looks terrible.. and marble is easily discolored I heard. Your advise would be appreciated! My stone is similar to what they’re installing, but with wider pieces.

    Reply

    • I think a 1/4 inch square notch trowel would probably be the correct size but it always depends.

      White thinset mortar is what you are going to want to use. Yes, the kind that’s a powder and you add water to it. Premixed adhesives aren’t what you want for marble.

      For grouting, you’ll want to read the instructions for all products involved- including the marble. But presealing might be a good idea. Either with a natural stone sealer or with a grout release.

      Reply

  27. Sir i am installing 32″×32″ porcelain tile what is the recommended notch if i have very flat stucco and i also want to backbutter tile

    Reply

  29. Installing 18”x18” x 3/8 porcelain tile on a flat smooth concreat floor . Would A 1/4” x 1/2” notch trowel , be sufishent , and would you recommend back buttering as well ?

    Reply

  30. Hi Jim ,
    I have porcelain tile that is 4×24 and I was told by a tile guy a 1/4×1/4 trowel was ok . I am half way thru my house and read on another place should have been 1/2 x 1/2 trowel . This is my first time doing this so I’m confused and will what I laid so far be ok ?

    Reply

    • Trowel sizes are only guidelines. The only thing that truly matters is how well the mortar is covering the back of the tile. You want to aim for 100% coverage. So I would check the coverage on the backs and let that tell you if the size of trowel is ok, or not. My guess is that you will need to step it up to the next size. You might also try back buttering the back of the tile if you aren’t already doing so.

      Reply

  31. i’m installing 12.01 x 12.01 x 10mm mosaic stone tile on a mesh backing for a kitchen back splash. the individual stones ar 9/16″ x 1-7/8″. what size notch trowel would you advise?

    Reply

  32. I bought some Purple Stained Natural Seashell Backsplash, 1″ x 1″ Square Shell Bathroom Wall Tiles (BK011) in 12 x12 sheets and am going to put a 16″ back splash around the kitchen above the counters. What size Trowel should I use?

    Reply

    • Looks like I missed this one. You’ll have to experiment a bit and see which one is right for you. I would guess a 1/4×1/4 v-notch trowel but you may find otherwise once you get to installing the tile.

      Reply

  33. Hello, I am installing 3×6 subway tile as a backsplash and am wondering which trowel to use. I was told by the employee at Home depot that the 3/16 x 5/32 V trowel is what I need but since the longest dimension of the tile is 6″ the adhesive states to use a 1/4×1/4 square notch. Who is right?

    Reply

    • Manufacturer’s instructions are always better than the store associate. In my personal experience, the 1/4 inch square notch is the way to go when installing the average 3×6 tile as well.

      Reply

  34. I’m installing 12 x 24 tiles next to hardwood floors, over Detra Heat 1/4″ membrane. Would a 1/4″ trowel be okay for the tile to make sure they are flush with the hardwoods? The hardwoods measure 3/4″, but with 1/4″ membrane, plus the tile, I only have about 1/8″ to the top of the hardwoods when I dry stacked them.

    Reply

    • The size of the trowel determines the amount of mortar underneath the tile to support it.

      No matter how thick the hardwood is you still need proper coverage underneath the tile and I don’t think a 1/4 inch trowel will get you there.

      Reply

  35. I’m using a 1/4×1/2×1/4 U-notch trowel with ProLite mortar. The combed notches are coming out too thin unless I clean and wet the trowel with a sponge before combing the mortar. I think the prolite is sticking to the trowel. Is this normal or am I mixing the mortar too thick?

    Reply

    • If you mean that they aren’t tall enough then that probably has to do with the angle of the trowel. But I think you are talking about width. This can be from having too little thinset that you are troweling but it’s also usually a sign of thin mortar- not thick. If it’s thicker mortar then you usually have no trouble getting the notches to take shape.

      Reply

      • I do mean width. Too much space between ridges and the ridges look like tall narrow v-notch ridges. That it’s too thin is surprising. It’s thick enough that if I pick up a gob with the margin trowel, hold it upside-down and shake it a bit, the stuff doesn’t really slump or wobble. The ridges I do get stay up on the wall very well. The light-weight stuff is tricky, I”ll have to play with it more.

        Reply

        • It’s hard to say. Measuring the water and dry mortar prior to mixing will tell you if you are in the right recommended range. If you are in that range then it should be OK.

          Reply

          • Mixing it according to instructions made for a better notch but thicker, wetter, stickier mortar and it’s harder to press a tile into it. Is it a bad idea to mix the mortar with a bit more water than the instructions specify so it’s easier to adjust a tile on the wall?

          • There’s a water range that can be used. So, yes, you could try adding a little bit more water if that’s preferable. But thinset is sticky by design. You might try wiggling the tile across the notches also to collapse the ridges of the mortar.

            Additionally, the mortar manufacturer will have instructions for how to mix. Usually, this is a certain amount of time (2 minutes?) and involves letting the mortar stand for maybe 5 minutes and then remixing. Each product can be different but following those instructions will help with the consistency of it also.

  36. Thank you for the information! I’m not sure which trowel size to use. We’ve got 3×12 inch tile for the shower so we’ll need 95% or more coverage, and I’m not sure if I should go 1/4 x 3/8 or 1/4 x 1/4. Your help would be appreciated!

    Thank you

    Reply

    • Those would be the two that I recommend. You might try one of each and see which one works better. It’s not possible to say which of those two will work better without taking in more factors

      Reply

  37. Our handyman contractor installed a niche on outside wall. He did not put form board behind it. Do I need to remove durarock and reinstall with foam board and re install durarock. I am concerned as it is a outside wall. Or what other options could I do?

    Reply

    • A shower niche in an exterior wall isn’t something that is ideal. But if one of installed then it’s a good idea to insulate it. I would give serious consideration to removing what’s there and doing what you can to add some insulation.

      Reply

  39. I am getting ready to purchase a trowel where the Notch, Depth, and Space in between is 3/8. Would this be ideal for 12×12 inch wall tile in the bathroom over Hardi Board?
    Or will a 1/4 x 3/8 inch trowel work?
    Thanks

    Reply

  40. Just wanted to drop a hearty THANKS to you and your site. You give excellent advise without the “I’m the only one who’s right” attitude. I’ve been installing tile for decades and happened upon your site for some info on a tile I hadn’t laid before. Found my answer quickly and it was simply your basic comment: more thinset is better than less. Thanks again for common sense approach to problems and God bless you and your endeavors.

    Reply

  41. I’m making a “tile picture” to hang on the wall above our gas stove (the space between the range hood and the range). I purchased 4″ x 4″ tumbled marble tile (irregular surfaces on all sides, about 20 pcs total). All pcs. have a in bedded ink picture and when combined in the correct order – make the finished puzzle picture. I will be using a custom building product (tile lab surface guard) on each individual surface face of the tile before tile placement. I’ll be using 1/4″ hardibacker board to put the tile on. Custom building products recommended their FlexBond thinset for bonding the tile to the hardibacker (moisten the hardibacker before spreading their thinset). After reading your article on trowel size, I’m not sure I selected the right trowel. I purchase the 3/16 x 5/32″” v-notch and thought of using that for the hardibacker and also backbutter each tile and use a 1/16″ spacer (really thin thickness wise) and inbed at each corner into the cement while placing the tile to keep everything lined up because of the tile being irregular from being tumbled. Custom recommends using their polyblend unsanded grout to finish. The grout line is going to be so thin, should I be using a grout bag to directly insert the grout into the tile joint? I guess I’ve laid out the process I feel I can use but anything you have to offer by way of experience would make me feel better/more confident in tackling this. I probably have $300.00 wrapped up in this 16″x24″ picture already not counting the framing that needs done yet. Help?

    Reply

    • My guess is that you will want to use a 1/4 x 1/4 inch square notch trowel and still back butter each piece prior to installation. You’ll want to make sure to use a white mortar to install the tiles with.

      I question the use of an unsanded grout. The tumbled marble tile that I’ve used before are too irregular to use an unsanded grout with. Unsanded grout should only be used with tight grout joints. I would recommend a grout like Custom’s Prism grout which is better quality and has more flexibility in the grout joint width. However, it is fast-setting and you’ll have to be careful not to let it sit on the surface too long.

      I’d also like to see you use a better quality sealer. Custom also owns the Aquamix line of sealers and I like both their Sealer’s Choice Gold (water-based) and Ultrasolv (solvent-based) sealers.

      Reply

  42. I want to install 4 1/2 × 12 bath wall tiles. Using 1/2″ durock as backer but it seems too flexible. Will installing more studs eliminate that? Also installing new valve body. How much of the plaster ground should be protruding from durock before I start tiling. I’m afraid it’ll be to much or too little otherwise the escutcheon won’t line up correctly. Also what size spacers between tiles would look best. There aren’t any grout bumps on tile. I assume a 1/4 x 3/8 notch should be used? Does thickness of mortar play a large part of overall depth. Thanks.

    Reply

    • If your framing meets code, which is 16 inches on center, then the backer board should be fine. You can always add more supports if you want.

      For the plumbing valve, the depth varies from manufacturer to manufacturer so you’ll have to follow their guidelines. Most plumbers will set them to the minimum expected depth. For example, you have 1/2 inch backer + say- 3/8 inch tile. So you’ll want to set the minimum to 7/8 inch past the framing. You can always exceed the minimum and maybe you end up at 1 1/8 inch. That’s OK.

      Minimum spacer size is 1/16. If you have a glazed ceramic tile then that’s probably a good spacing. It’s OK to go more.

      Reply

  43. I am using 20 inch X 20 inch polished natural stone tile on my shower walls.
    Would you recommend a 1/2 trowel?
    Would 1/8 inch joints be acceptable?
    For showers, is there a thin-set at the big lot stores you recommend?

    Reply

    • Yes to the 1/2 inch trowel and 1/8 inch joints are acceptable. I would use a white LFT mortar from the big box store. Marble & granite mix, large format tile mortar, or something along those lines.

      Reply

  44. I’m hanging “thin” brick as a backsplash. The manufacturers website says use a 3/8 x 1/4 trowel. I see a lot of them are listed as 1/4 x 3/8 x 1/4. Is this the same thing? Thanks

    Reply

  45. Hey Tile guy,

    Putting 6×24” plank on a shower wall and floor with Kerdi on wall and deitra on floor Should I use 1/4×3/8 or 1/2×1/2 square notch.

    I need to come up 3/4” to hardwood. So 1/4×1/4” to set 1/4” ditra. Than what trowel to get me up with 5/16” thick tile? Thanks

    Reply

    • I’d probably use the 1/2 inch notch trowel for doing 6×24 tile. Assuming your using normal Ditra which is 1/8 inch thick then you might have to build up a bit to get things to flush out.

      Reply

  46. First – great site. Thank you for putting this together. We’ll certainly be using affiliate links where possible.

    We have a question regarding Tile Leveling Systems. As part of them permanently remains under the tile, can some of them require a slightly thicker notch?

    Here is our project and application materials. We have not yet selected a tile level system but will want one that has a tool, rather than just clips and wedges.

    SHOWER
    – Wall and Ceiling Tile (horizontal off-set brick pattern):
    https://www.flooranddecor.com/porcelain-ceramic-decoratives/esenzia-note-ceramic-tile-100410984.html#prefn1=color&prefv1=Blue&start=6

    – Floor Tile (herringbone pattern)
    https://www.flooranddecor.com/porcelain-tile/new-york-soho-brick-look-porcelain-tile-100086917.html#prefn1=shape&prefv1=Rectangle&prefn2=size&prefv2=4+x+8&start=1

    Thanks very much!

    Reply

    • Yes, some of the bases are thicker than others and could require more mortar. I don’t know the ins-and-outs of all the different systems but I use the MLT system with the one-piece (T2) straps and have never had an issue with the base strap bottoming out. However, I tend to only use leveling systems with large tiles.

      Reply

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