Thinset for Tile…DO’s and DON’Ts (Quick Tips with Sal DiBlasi)

Thinset for Tile…DO’s and DON’Ts (Quick Tips with Sal DiBlasi)


Hi, I’m Jeff Patterson, founder of Home
Repair Tutor. And I’m Sal DiBlasi, Elite-tile Company.
I’m from the Boston area. And I’m in Pittsburgh. So we figured even
though I’m a Steelers fan—I’m sure you’re a Patriots fan—we’ve come together to
make this great video on thinset. We’re going to divide the video up. I’m
going to be talking about some areas that I made, especially spot bonding. And Jeff
is going to talk about the proper methods of…
How to apply the thinset to the back of the tile, commonly known as backbuttering and
the pattern of the thinset that you want to see whenever you’re applying it to the wall
or a tile. One of the major problems when installing
tile is the actual application of the thinset and the troweling and just the coverage of
the thinset. So we felt that it was important to give some good information on what the
proper methods are and what the problems are. So these quick tips, hopefully they help you
with your own project when it comes to tile work, and they help you do the project the
right way. So we’re going to be jumping into the video. The first part of the video
is going to be Sal sharing his knowledge about what you should do, what you shouldn’t do
with the thinset. I’m going to go over one of the most common
areas, and Jeff is going to give us some information on the things you should actually do.
So, we’re going to jump into the video right now.
Thanks. Okay, so what we’re going to talk about
today is spot bonding, which is an improper way of installing tile on a surface, whether
it be a wall or a floor. Now what is spot bonding? Spot bonding is when you get a tile.
You mound globs of thinset on the back of the tile. Most of the time it’s like five
globs, but sometimes there will be six or nine. But it doesn’t really matter how many.
The point is that they put globs or mounds of thinset on the back of the tile. Then what
they’ll do is they’ll get that tile and push it into the surface, whether it be a
wall or floor. And the reason they do this is because it makes it easy for an installer
to get a flat, even surface and get very little lippage or eliminate lippage because they
can push the tile in and out a corner or whatever and get the tiles even. The problem with that
is that thinset is not designed to be used in globs.
What happens is you got the tile on your wall, let’s say, and you’ve got these mounds
and you push them into the substrate, and you got a nice, even surface. Now in the back
of the tile, you’ve got all kinds of voids. Very little of the tile is actually supported.
So you’ve got a lot of empty spaces behind the tile.
And the other issue with that also is that the thinset, as it dries, it’ll shrink,
pull away from the tile, and leave the tile with very little support and very little bond.
Now some guys will also spread a layer of thinset with their notch trowel on the surface
and then they put the mounds on the back of the tile, the spots, and then they push it
in, thinking that that way they’re going to get good coverage. Not true. Doesn’t
happen. There’s still going to be a lot of empty spaces.
Another reason to do this is because you can avoid doing the needed prep work. If you’ve
got a rough surface and it’s not well prepared, you can get a flat, even surface without doing
hardly any prep because you got these big globs of thinset behind the tile. So doing
it this way by the time you’re done, and you’ll probably going to have a nice, good-looking
tile job, even, etcetera, etcetera. But in short order, you’re going to get all kinds
of problems. Because the tile isn’t properly supported—I’m
just going to go over these details on how to spread your thinset, what kind of coverage
you’re supposed to have, etcetera, etcetera—because you don’t have the recommended coverage
and you don’t have the support that the tile needs, it’s subject to cracking very
easily, to become completely unbonded to the floor, the corners can crack, you can break
off all the voids behind the tile; it’s just a big, huge issue.
So if you’re in a dry area, you’ve already got huge problems. Now if you do that in a
wet area, you’ve got even more problems. Because, let’s say in a shower stall, you
got all these voids behind the tile. You got all these empty spaces. And the water in the
shower is going to penetrate behind the tile. And as it gets behind the tile, it’s going
to accumulate, and you’re going to get mold and mildew and who knows what else growing
behind that. So that’s another problem. And then the tile can also discolor, and depending
on the kind of tile, you get dark and light areas of tile, discoloration, all sorts of
things. Have you ever even seen mold especially on natural stone? Have you ever seen mold
grow inside the tile? The actual tile has mold growing in it.
So if you’re going to install tile, you need to use proper methods, proper procedures
so that you don’t run into these issues. Yeah, sometimes you can find a method that
is going to make it a little bit easier, that’s going to give you a good-looking job with
less effort. But by not getting the coverage that you need for the tile, for the thinset,
in short order, you’re going to have all sorts of problems.
These are just some of the problems that you can have. Jeff is going to go over the main
points that you need how to use thinset and what you need to achieve for proper calibration—that
kind of stuff. So I’m going to hand it off to Jeff, and he’s going to vie you some
good information that you really need to know. In this part of our video, we’re going to
be talking about thinset coverage and backbuttering. Is backbuttering absolutely necessary? It
is absolutely not. But it does provide you with extra insurance that your tile is going
to stick to the substrate. Many of the tips that you’re going to see
here in a second come from the TCNA handbook. If you’re not familiar with the Tile Council
of North America handbook, check it out. It’s a really great guide.
So for example, in the TCNA handbook, they recommend that 80% of the back of the tile
be backbuttered if the tile is going to be in a dry area. What do you do for a tile that’s
going to be in a wet area like a shower or a bathroom floor? Well the TCNA recommends
that 95% of the back of the tile be covered in thinset. We’re going to go over that
in a moment here. Also, you want the thinset to be evenly spread
on the back of the tile. You don’t want 20% to be right here, and the other 60% to
70% of it to be all over here. Just evenly spread the thinset on the back of the tile.
The other super important thing when thinking about thinset coverage is the size of your
notch in your trowel. So here is a KERDI trowel. It’s a 1/8” x 1/8” square notch trowel.
You would never use this to adhere or set tile to a wall or floor. It’s only good
for KERDI-Board. This, on the other hand, is a ¼” x 3/8” x ¼” square notch trowel.
And this is a really great option for certain tiles.
And by the way, if you’re looking for a recommendation on how to choose the correct
trowel size, click right here. There’s a video by Sal that’s phenomenal. You should
definitely check it out. All right, let’s do some testing.
This is just a standard 12” x 12” tile, and I’m going to turn it over. As you can
see, the back of this tile is not flat. If it were, you could technically use a smaller
trowel and still get good coverage on the back of the tile by backbuttering and by using
directional troweling on the wall or the floor. But as it stands, you can see this is not
flat, and you have a lot of voids in here, and there’s porosity to the tile. Because
of all the voids on the back of this tile, it is advantageous to backbutter it because
you’re going to fill in all these voids and the pores with the thinset. And this will
make it easier to achieve recommended coverage when the tile is placed on the comb thinset
that’s on the substrate. Okay, so let’s dive into our test. Test
number one is going to be using this Schluter-KERDI trowel. Totally undersized. Definitely not
meant for adhering tile to a substrate. This first test, we’re just going to spread the
thinset onto the substrate here, which is KERDI-Board reversed. So we’re just going
to trowel the thinset on one direction. Here’s our thinset. We have our directional troweling.
So all the ridges are going in one direction. We’re just going to put our tile on it and
push down firmly into the KERDI-Board. So I’m going to take this tile off and turn
it over for you. If this tile were white, it would be even
more apparent. But the coverage here is terrible. It’s not great. None of the thinset is in
the voids of the tile, and that’s not good. This tile would definitely come up off the
substrate over time. So this goes to show you that an undersized trowel is not good.
This next test, we’re going to be using a ¼” x 3/8” x ¼” square notch trowel.
And what I’m going to do is show you why directional troweling is super important.
Directional troweling is basically north, south, east, west—all the trowel ridges
are in the same direction. Sometimes when you see videos on YouTube, you’ll see somebody
do these swirl patterns. So no backbuttering of the tile here. We’re
just going to set it firmly into the KERDI-Board or whatever substrate you want to pretend
this is. And we’re going to move it back and forth, too. All right, let’s go ahead
and pick up this tile. So look. This is why directional troweling is good. This is a fairly
big notch. You can the trowel ridges are not collapsed. There are air pockets in there.
And the back of the tile isn’t very well covered at all. There’s lack of coverage
here for the thinset. I don’t even know what this approach is in terms of the coverage.
Not good. Definitely not 90% to 95%. So that’s why directional troweling is super important.
For this next test, we do have directional troweling. All the ridges are running in the
same direction. And we’re going to backbutter the back of the tile using the flat side of
the trowel. So we’re going to fill in all the voids. So we pretty much have almost 100%
coverage on the back of this tile. So this is backbuttered with the flat side of the
trowel. Now we’re going to embed it into the directional ridges here. And we’re going
to move the tile back and forth. We’re going to collapse the ridges. All right.
Now let’s take a look at the back of this tile. So as you can see here, we’ve got
great coverage. All the ridges were collapsed. The air is allowed to escape from those ridges.
So when you collapse the ridges, the air is expelled from them. And you collapse the tile
onto the thinset, and you get great coverage. As you can see, all the voids in the back
of the tile are covered in thinset. And it’s really the collapsing of the ridges that provides
the coverage. This final test, we have directional troweling.
So all of the thinset is in one direction on the substrate. And we’re also going to
do directional troweling on the back of the tile. So the direction of the notches on the
back of the tile match the notched pattern on the substrate. So what we’re going to
do is adhere this tile to the substrate. I’m going to clean this tile off in a second.
But we’re going to collapse the ridges. We’re going to move this tile back and forth
just a little bit to collapse those ridges. Expel all the air out of the thinset.
All right, let’s take this tile off the KERDI-Board. And again, you get great coverage
when you use directional troweling, and you use the double-notch technique.
Well that’s it. Hopefully you like these quick tips and they help you out with your
own project. Make sure you subscribe to Sal’s YouTube channel. It is phenomenal. If you’re
doing tile work, you definitely want to watch a lot of his videos.
And don’t forget to subscribe to Jeff’s channel because he has some really good information
in his channel, and I think you’re going to get some really good value out of what
he does. And don’t forget Home Repair Tutor as well.
Well thanks so much for watching and make sure you leave your comments down below. We’ll
definitely try to answer them, and we hope you have a great day.
And remember, subscribe.

97 thoughts on “Thinset for Tile…DO’s and DON’Ts (Quick Tips with Sal DiBlasi)

  1. You guys are awesome. Big thanks to Sal as always. Not sure if it's a big enough topic for a collab video but any ideas on installing accents that may be thinner than surrounding tile on different substrates. Thanks guys!

  2. What brand of non modified mortar do you guys recommend for using with Schluter kerdi? I have seen guy recommend mapei kerabond which is a premium mortar. My issue is I cannot find a local business that sells it. Any other brands that would be a good fit. I've read that the big box store brand non modified mortars are not that great. Thx

  3. Do you recommend Tile adhesive mat like Simple mat the ones sold at Home depot for small tile jobs like mosaic backspalsh. Thanks

  4. where can you get the tcna book? and personally i dont double notch i find it harder to keep lippage at minimum but i do back butter all my tiles

  5. thanks guys I'm in the process of redoing a bathroom I'm almost ready for tiling I'm going to water proof with redgard water proofing agent with a mesh. the videos you have done have most likely saved me alot of grief. Thankyou very much.

  6. A good video would be to show how you properly prepare a very uneven room both in timber frame and a brick built room

  7. I have been watching all your videos and it has really helped me. My big question is I am ready to tile both the walls and the floor. The floor is 12" sq's but the walls are Lowes, Anatolia Tile Chiaro Tumbled Subway Mosaic Travertine Wall Tile (Common: 12-in x 12-in; Actual: 10-in x 12-in)
    Item # 260587 Model # 20-513 two different worlds. Which one would you do first the walls or the floors is my big question. Thanks, Tom
    Pittsburgh, Pa

  8. I've never done any home repairs but my engineered wood flooring is starting to popup despite my home being only 8 yrs old. I plan to replace with tile and am considering doing the work myself. Should be easy right, haha.
    These video help a lot but also show common mistakes and leave me wondering  how well did the developer follow proper procedures for tiling the bathroom and shower.

  9. When you lay pebble rocks is there a trick to not make it look like a grid of rocks or do you hand stick the majority of them ?

  10. I'm also curious as to how thick I should expect the final outcome . The tiles I'm using are 1/4" thick , and I believe I read that 3/8" thinset ends up being 3/16" thick when compressed ? So my added thickness would be just under 1/2" thick I think .
    The reason I ask is , I'm putting the nipples in for the showers wand and tub spout , and need to know the final thickness

  11. "Proper methods, proper procedures"…
    Its not like companies dont spend lots of money (with highly educated staff) figuring out what does and does not work. How some diyer or guy at home depot knows better… i have not a clue.

  12. I need to set 6 24×24 ceramic tiles onto hardybacker on a floor with no exposed grout lines… what should I do ?

  13. Good info. It would be less painful to watch and listen to if you script your message so you’re not droning on and pausing a lot.

  14. So I did the directional 1/4 inch trowel and also did the directional back butter on 12×24 tiles. But I did not mash down or put too much pressure on them as I layed them in place. Do you think I will have problems down the road?

  15. What happens when the builder/customer you are working for doesn’t pay for the extra prep work required to do it the right way…I’ve got a huge problem with that here in Oklahoma

  16. Kerdi systems hardibacker dance Shield they're all fast way of doing a shower not precise by the way they are all fast ways of doing a shower mudding is shower is the best way.

  17. By the way why can't I ever find a video where I can see Kerdi Schluter being adhere to a substrate levels like you all show in your videos

  18. I can’t believe back buttering isn’t required to all tiles 12×12 and larger. I wish you would have done directional trowel with no back buttering and looked at coverage.

  19. My curbless shower base has vinyl liner extending between pan and concrete floor. Should I trim it off level to the floor or caulk it to the floor, and tile over the excess liner?

  20. Everyone sucking Sal's dick, I thought his part was pretty bad, he filmed in his home office? With no examples at all? Kept repeating the same thing over and over? The younger guy did great and you can obviously tell that he is muchhhhhh better at speaking on videos, you the man!

  21. Appreciate the video, and your point is taken. However, you need to study up on the scientific process if you are going to perform comparisons like this and expect folks to take them seriously. Each one of your examples was done differently, and you expected each to come to the same result. It doesn't really work that way. I've enjoyed your other videos, this one was disappointing.

  22. Great that you showed the examples of each. Can't believe anyone would use the "blob method"!

  23. Great Video! thank you and PLEASE Take off the iWatch next time? accidents do happen even if you are skilled with thinset

  24. The rationale provided for each method of back-buttering, WITH the demo's, provided the WHY for the right trowel and directional application.Great video. Suggest minimizing the verbal and maximizing the show and tell. Good work!

  25. this is great and everything but it says nothing about tile trim and now I'm in a real pickle because I've installed the tile WITHOUT putting tile trim in. If you're going to leave such a crucial step out like this then don't even bother making a video… now what the fuck am I going to do?!?! How??? How do so many videos leave this step out?!?! And seriously… what am I supposed to do now???

  26. no offense to anyone but god dam do people from their neck of the woods talk ugly .
    im from california by the way and they probably dont like how i talk.

  27. Is that how thick you normally mix your mud?????? Looks thin to me. We usually mix
    ours much stiffer. Good video, people need to see this.

  28. So yeah, that second part of the video is the right way to do it. For example, subfloors are not nice and flat everywhere…ever.
    Yeah you can tell me to get the self leveling to make it straight…it's $50 a bag and barely covers anything.
    If I have to price on every job I have to bid on, I will never get work. Common homeowner has no clue what's the right way and what's not. For him has to be cost effective and to look nice at the end.
    Also on the other hand, per the statistics, people don't stay more than 7 years on average in a house. Nothing's meant to last forever…for christ sake…10 years ago style is not the new trend anymore either. People will change their bathrooms a lot more often than it used to be 10 to 30 years ago. So yeah, you don't really need to do it same way you explained it because nobody cares after all.
    If you want everything to last a lifetime…start with building the whole house the right way.
    Also if everything lasts a lifetime, you and me won't probably have a tile job anymore.
    Good informative videos for DIY, but all this is just to get traffic on your channel and use it for marketing purposes after all. Not every house/project is the same.

  29. You were a little bias, the last method you were sure to really move the tile around to make sure it set well in the thin set

  30. Thank you so much for this video. I have tile in kitchen that is tenting and needs to be repaired. After watching Sal explain what not to do I understand now why the tiles are tenting. I'm going to use the techniques Jeff demonstrated when I redo the tiles. Thanks again. Great tips and very helpful video.

  31. first 1:45 of the video,……. we're going to talk about x… next 1:30 we're going to
    talk about x. my God get to the point.

  32. Is back buttering necessary on smaller format tiles such as subway tile. I am about to remodel my bathroom and have noticed a lot instructional videos on subway tile not back buttering.

  33. Flat trowel back butter then use a 3/8 trowel directional thin set . The rest is overkill unless you need to float a low tile up .

  34. Jeff if you’re going to waste that much time on back buttering the tile, just use 1/2 trowel and the job is done With out the extra work

  35. Jeff your growing on me a little. Wasn’t sure about you in the first couple videos I watched probably your youth but I’m starting to soften my stance a little. Last couple videos taught even this old dog some new tricks. Not back butter and trowel stuff we knew that already.

  36. Why not show swirl trowled and a flat back butter? Seems like you missed that one to highlight your method. Swirl trowel will get plenty of coverage especially if you back butter and use the proper notch.

  37. That first issue is called "floating the tiles", and is a hack. I totally agree with that. It should NEVER be done. However, for the rest of the video, I disagree with your arguments.

    Sorry, I'll just say that I agree to disagree. (In relation to back-buttering, which you are clearly not doing right, or understanding the term.) I rip tiles up, to replace them, across whole floors. The point of the raised lines is to reduce the quantity of thinset used, but keep adequate coverage to bond. You are not trying to "completely cement the tile onto the cement". You WANT to retain the voids. Otherwise you will be there for weeks trying to rip-out tiles WHEN it is time to replace them. (They don't last forever.) They will be forced to shatter into tiny pieces and not one of them will "pop-off", like they are intended to do, when the voids are there.

    By the way, back-buttering is when you trowel the lines onto the tile, instead of onto the floor, and should ONLY be done on pieces where you can't apply thinset onto the floor itself. It is not just "Skimming" a thin layer of thinset onto a tile, then sticking it to a troweled layer, which is already on the floor. That is honestly just dumb. You just wasted thinset on the tile, where it isn't needed, and made it a solid backing. Those ridges are for structural integrity. Like how an "I-beam", is stronger than a solid plank, or how a fluted-form on sheet-metal is stronger than a solid chunk of sheet-metal. If you did that, and also "floated" the tiles, they would flex and break when you walked on them. Possibly even when you correctly trowel them too. (But less possible, if troweled correctly. You just wasted thinset filling the voids in the back of the tile, at that point.)

    Also, if the bond is solid, and the thinset "shrinks", it will crack tiles, especially if it is on plywood or thin cement-board, or it will crack the cement-board. The less volume, the less it shrinks. If it has the trowel-lines still there, under the tile, it shrinks the lines to be more narrow. Without the lines, as a solid bond, it shrinks the full width of the tile and will actually pull itself off a greater center portion of the tile. You are also defeating the second purpose of the troweled lines. That is to make height adjustments for unleveled floors. Giving you room to tamp down higher pieces and leave lowered pieces with an adequate bond, which can't be tamped-down, as they are already as low as needed.

  38. As long as you use the RIGHT thinset spot bonding is fine on walls. You guys are wrong for this. I live and work in NYC and spot bonding is used to install even huge slabs of marble and granite on buildings. Hope you make money from these videos though.

  39. I don't have a single straight wall in my house. Same as you. To show how to apply cement to the tile, it's just a joke.

  40. back-buttering 300*300 tile??? I think it was totally unnecessary. I will not back-buttering any tile less than 800*800, I would rather spend good amount of time on surface preparation.

  41. Thanks for the info on the Thinset. I have kitchen, bathroom floors that have hollow void and need to be replace. What is the best why to repair any suggestions would be gladly appreciated.

  42. Thank you for the video, I have a tiled fireplace and want to get a stoney effect, is is possible to tile over the existing ones? Or Ideally I would like to get a split stone effect using white cement or PoP something along those lines, If possible what would be the best medium for this? Thanks

  43. What would be the best thinset to use on my 4×16 ceramic tile job . walls are 1/2 thick durock sealed with red guard . thanks in advance for your reply .

  44. thanks for all the valuable information! definitely never thought of any of these things (I've never really laid tile before, but want to)

  45. Pros apparently spot bond, its so shit and they are the best at what they do, sadly DIY users pay pros to do tile work and then have to go back and fix it themselves.

    Thanks to youtube and a lot of these channels, a lot of info, a lot of time on here but its a lot clearer the simple steps that need to take place for a proper job.

    Thanks again for the great content.

  46. this has got to be one of the most ridiculous things Ive ever heard,,I have laid miles of large format tile on all kinds of substrates using spot method with medium bed thinset and have NEVER had an issue ,,,,there is no such thing as a perfect sub floor so if you just go and trowel jobs gonna turn out crapy,,this may be ok for homowners but not for someone trying to make a living at it,,if you do it right there is no problem ,,,,tell us how you fix an uneven tile ,,, what you should be doing is a vid on these leveling systems where guys use mass amounts of lose mud then lift the tile to get it even leaving a void.,, and how does the distance between the wall/floor and back of tile create a moisture problem? PEOPLE WAKE UP !!! ,,,just because its on you tube doesn't mean its true or right ,

  47. Classy pair of professionals. I like how they compliment and promote each other. Everyone can learn from this, and we can all learn something from every person we come across. Thanks for the video.

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