To Back-Butter or Not Back-Butter, That is the Question

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Shakespeare said it a little different in the opening of Hamlet, but if he was talking about the concept of back-buttering tile, he may of stated it as above.

Back-buttering tile may not have been an issue in his day, but it’s still debated among seasoned tile setters in 2013.

Answering the Back-Butter Question

Back Butter Tile

To educate or refresh what is meant by “back-buttering”: The phase back-buttering describes the process of applying a thin layer of thinset adhesive to the back of the tiles using the flat side of the trowel. This is done in an attempt to provide as close to 100% coverage of the setting mortar to the tile just prior to setting it into the combed thinset that has been applied to the substrate surface. The objective here is clear – set the tiles in such a way as to reduce the possibility of failure. Many factors must be taken into account in every tiling situation and no two installations are exactly the same.

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The folks in the tile industry have provided us with many exciting choices. Many of the tiles are large format tile. The Tile Council of North America (TCNA) and the National Tile Contractor’s Association (NTCA) describe large format tiles as “any tile measuring 15 inches or more on any one side.” With these types of tiles it’s VERY important to apply enough supporting adhesive under them. One of the best ways to ensure the proper amount – and coverage – to these tiles is by back-buttering them. All natural stone products also need to be back-buttered. Travertine, marble, granite, slate, etc., are natural materials. Many have voids in the reverse side. By back-buttering these types of tiles the installer is filling in the voids giving additional strength to the weaker areas. This is again done in the attempt to achieve the original goal, “Set the tiles in such a way to reduce the possibility of failure.”

I think by now you have figured out which side of the fence I have landed on. I can’t see why an installer wouldn’t back-butter every tile installed.  If you want a more scientific analysis of whether you not you should back-butter, check out the video below.

How to Back-Butter like a Pro

As a seasoned tiler who does back-butter, I have experienced the many difficulties associated with traditional back-buttering techniques, including arm fatigue and occasionally dropping tiles while trying to back-butter. I found that these problems can be solved by using “The Back-Butter Buddy.” Tiles can be stacked safely and securely onto the tool and with a simple spinning action, thinset can by applied to the tiles. Click here to learn more about this brand new product and watch it in action!

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Phil Green is the owner and hands on at PGC Construction Remodeling and Design for over 32 years. Phil has been able to hone his skills in all facets of the remodeling industry. Specializing in kitchen and bath remodels...Read more

47 comments on “To Back-Butter or Not Back-Butter, That is the Question

  1. Brad

    I’m a back-buttering fan. I find it gives the tiles a much better foundation and there’s usually less chance they’ll get worked loose. Fingers crossed!

  2. Phil Green Post author

    Yes Rob, you were taught right! Many tile setters and homeowners that set tile don’t know how important this is.Newer tiles are the same extremely hard, durable,non-absorbent material all the way through.This means that the thin set will not adhere completely if the tiles are just plopped into place.

  3. Darryl

    I agree with the back-buttering, it’s one of those corners that sometimes gets cut in the name of time, effort or extra material, but it definitely makes the difference in doing a good quality job for the customer.

  4. Tom

    I believe in back-buttering as well. You use more mortar but you don’t have to worry about the tile coming loose because of inefficient contact. The back-butter buddy could also be called a back-saver buddy; balancing tiles while on your knees give me a pain.

  5. Alicia

    Thanks for explaining and giving concrete evidence as to why I should back-butter tile. I’m going to be installing floor tile in my art studio and I wanted to be sure I was doing the best possible job to lay a beautiful floor that lasts.

  6. Sergey

    Phil, to be honest I never heard of “back-buttering” until i read your article. Now, once I am familiar with the term and technique, I clearly understand the benefits of “back-buttering”. Although it is more labor-consuming, “back-buttering” provides a much greater degree of support, especially for large and heavy tiles. Thanks for sharing.

  7. rick d

    i’ve been tiling for 20 years. back/butter is the trick with large tiles. the bond is unbelievable. if a contractor is doing your job ask him if he back/butters the large tiles. if he say’s no, look for another guy

  8. Andrew Mishura

    Thank you for making the effort to produce and share this compelling experiment. Just in time for me as I am planning to start tiling soon on a project for which I require a very high standard of quality.

    1. Chris W

      I just repaired 20+ tiles from a 200 square foot non back buttered floor including the cracked ones. I’m only half way through also. Butter them!!! Don’t take the chance.

  9. Matt

    In my own professional opinion, and experience, the non back buttered tiles would have performed as well in real world applications, on any of the substrates demonstrated, and the video only serves to prove that. Is it a little harder to remove the tile with a hammer and a crowbar? Maybe… Does checking the bottom of the tile visually for voids prove anything? No. Did any of the tiles pop off clean from the thinset leaving the underside fresh like a brand new tile? No. I do appreciate the video, but you came to the wrong conclusion. If backbuttering every tile allows you to walk away fron your work more confident, go for it. But on 12x12s that arent flat stock you probably are wasting your time.

  10. Phil Green Post author

    We can agree to disagree. Your closing statement about 12x12s NOT flat stock is exactly the reason that Back Buttering of the tile should be done. If you believe that it would just take too much extra time, or you just feel that back buttered or not, NO big difference, then go ahead and set your tiles like that. As for me, I will continue to BB my tiles, same way I have been setting for over 44 years.

  11. Matt

    So you’re saying it’s less critical to back butter tiles with a smooth back and no grid? I’ve always believed the opposite. Time is definitely a consideration on whether I back butter or not. I’ve done floors as big as 10000 sq ft without buttering and without issues. Haven’t been alive for 44 years but some of my floors have been around for over a decade, still solid and crack free. I would never argue wholeheartedly against an extra step for a better quality finish/product but personally, I don’t feel the need to butter every size tile in every application.

  12. Phil Green

    I misunderstood your comment “on 12x12s that aren’t flat stock” I read it as tiles that ARE warped. My position will stay that it is insurance and for sure NOT detrimental to BB any tiles set….and the BBB makes that quick and painless. I will also never be “that guy” that thinks length of time in the trade is the acid test for a setter to be better than another.

  13. Paul

    I don’t back butter 12×12 flat tiles either. Wouldn’t this defeat the purpose of using a 3/8″inch notched trowel? Or 1/4″inch trowel.

  14. Ryan

    Did the bb pieces have voids or because you back buttered you just couldn’t see the under side of the tile?

    My point is you can see the red on the ceramic not back buttered bc the color variation.

  15. Nichelle

    Wow, Phil, that was a very informative and helpful experiment, very useful in helping me tile bathroom in investment house–thank you! And your Back-Butter Buddy is a great idea- if I didn’t need to get my project done today, I would likely order it.

  16. Bill Landis

    I think back buttering is a must! Think of the tiles as a sponge. A dry sponge absorbs water whereas a wet one does not. So, back buttering keeps the tiles from drawing moisture from the thin set you applied to the floor. Besides, you get a much better bond.

  17. norim

    Wow I saw this post a little bit late but on the right moment. Last week I had to demolish a 10 year old floor that my father had laid without BB. It was evident that under the tiles there were empty spaces like holes of air. I can assure you that my father did lay the tiles well and did hit the tile well with the rubber mallet so I think the issue was with BB. The tiles were all laid OK and no tile was damaged or moving but I think that if something hard did fall on those empty spaces it could break the tile.

  18. bill mcguire

    in “most” all my tiling i have BB however i am presently doing a shower that will be completely ceramic tiled / ceiling included . because of the meshed 1″ ( 10 1/2 x 12 “) sheets would it advantageous to BB. keeping in mind these tiles are thinner then larger ones. also i will be applying the tile over the Kerdi system & secured using unmodified. thanks in advance

  19. Pat

    I am installing 2″x2″ tiles on an outside round table. If I back-butterdo I need to also apply the adhesive to the table surface?

    1. Phil

      2×2 tiles are mosaics. You DO NOT need to Back Butter that type of tile .
      Trowel thin set with the notched side of the trowel onto your table and then set the tile into it. Use a grout float to “tap” the tiles into the wet thin set to embed them.

  20. Derek

    Morning Phil! I’m getting ready to tile my bathroom with a 3/8 trowel and schluter ditra between the tile and substrate. Would you BB 12×12 tile along with using a 3/8 notched trowel? Im thinking yes.

  21. Jeff Wentz

    Phil I recently did a walk through with the builder of my new home. During the walk I noticed the shower wall tiles (12 x 12 and 12 x 24) did not appear to be installed in a mortar bed. It looks like they loaded the back of each tile with a pile of mortar and just pushed it on the wall. As a result I have substantial voids between the tile and the backer board. I have know idea of what they did on the floor. Is there any way to check with out tearing it up.

    I know enough that this method of installation is not acceptable but do you know which building code or standard I should reference. Builder disagrees with my assessment and had told me it will function and last just as long. Thanks

    1. Phil Green Post author

      You are describing what is known as “dot method “.
      You can reference the 2017
      TCNA ( tile council of North America) and see that this method is NOT approved for any area especially, a wet area like a shower. We are required 95% coverage for wet areas. No way dot method could achieve that.
      If you get push back from the builder, just ask him to sign a 15 year materials and labor warranty. I would the way I install. I think you might find him NOT as confident as he thinks.

      1. Chris

        Excellent answer. Many tile setters have little to no training and get away with shoddy workmanship while charging what professional craftsmen are worth. I say stick it to your builder!

      2. Lou

        The same tcna council that made the video with glass tiles on how to comb thinset properly that convinced me that bbuttering is useless? Trowel size combing direction and wiggle motion accross thinset beads is all that counts. I would bb only on uneven substrate.

        1. Phil

          I actually personally know the guys that did that video. I do not deny that coverage of thinset on the backs of the tiles is the most important aspect for a successful tile install, but they also agree that Back Buttering is benificial with all natural stone materials and large format tiles.
          BB’ing should never replace proper troweling techniques but can compliment them.

          1. Phil

            5 dot is NOT an acceptable installation technique as determined by the NTCA. NO WAY can you get proper coverage with that. PLEASE, EVERYONE understand that back buttering is NOT a replacement for proper trowel size and coverage. It IS a great practice and will give you some simple insurance for your install. Watch THIS video and you will see the PROPER technique for tile installation. https://youtu.be/Way5bMh-eYg

    2. Muhsin Kermalli


      Great post! As for builders and dot style..I’m seeing so many so called pro’s do this. I had an argument with a guy who agreed that 90% coverage is good but still maintained he can achieve this by dot style…so the following week I checked his work on another site and sure enough he was way off but still argued he had sufficient coverage. The issue is also that new builds have the trades in and out as fast as possible. So all the trades try to go quick and as long as it’s done and grouted and looks good they’re off. How many times have we seen mold growth as a result of dot style. We need more understanding of the hazards mold causes especially in todays world with so many allergens and toxins we have in our environment. I always try to explain that if you install the right way and take certain precautions you only are helping your own household.

    1. Phil

      NO! never introduce water to backs of any tiles.
      Water is a bond breaker and you thinset will NOT stick to it.just back butter the thinset to the backs of the times using the flat side of your trowel and then embed them into your combed thinset on you floor

  22. Steve Alderton

    I am confused. I have read about and understand that backbuttering on large format tile is a must. I can see that applying a thin layer of thinset to the back of a large tile can assist with bonding of the tile to the combed thinset bed. But this buttering is very thin. Less than a 1/16″. It does not fill in uneven areas of substrate. It does not level out warped/bowed/twisted tiles. It only helps create a better bond when the layer is forced into the “grain” of the back of the tile. The filling in of voids caused by bad substrate or tile can only be handled with the combed mortar. The tile must be placed evenly, moved back and forth perpendicular to the direction of the comb to collapse the comb, allow air to escape, and create the bond. Many failed installations are because of substrate movement, poor bedding technique, mixing too much thinset that you can use before it starts to dry out, application over uneven substrate without correction prior to laying tile, etc.
    If your price is competitive with you back buttering every tile from 12×12 up, then by all means, keep it up. But proper adhesion comes more from proper bedding, in properly combed thinset, with the proper mix of water/thinset.

    1. Phil

      Steve, Please read my response a couple posts up…. Back Buttering is just SCRATCHING the thinset into the backs of the tiles to help activate the “fingers” in the thinset for good bond. YOU ARE CORRECT that proper trowel size is what will get you COVERAGE….. Here is the link again. https://youtu.be/Way5bMh-eYg

  23. Toni

    I came looking for an answer for 2-1/2 x 12 inch ceramic (maybe porcelain) tiles used for a backsplash, but I still don’t have an answer. None of the videos I’ve watched backbiter, but they also are not using the NTCA guidelines for putting adhesive on “directionally” and not swirling. I did watch that entire video and it made complete sense to me.

    Do you have this question answered somewhere else or can you answer it please? Thanks.

  24. Jeremy Davis

    Back buttering is great if you have the time and are being paid for it. With the horrible unlevel floors and competitive prices here in the south it’s just not feasible. If you take the time to bb every tile around here they’ll replace you. Like I said,if you have the time and are getting paid for it then cool. Around here time is money and the normal, slake, combed thin set, and gap bridging is more than enough. Is all that is required because it works. Got that from the mapei representative himself

    1. Phil Green

      Jeremy, I hear that all the time. I don’t buy it. If it takes you 30 min longer to back butter your tiles for a quality set, you really think you would lose jobs because you were 1/2 hr slower than someone else? I know MANY Mapei reps. I don’t know to many that would tell you NOT to back butter given the conditions of the substrates you note in your comment.

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