I constantly reiterate the need for a tile installation to be flat. Not necessarily level, but always flat. This is the mark of a true professional and the thing that turns an ‘okay’ installation into a spectacular installation. (Did I just type ‘spectacular? Jesus…) Anyway, the method I use on floor tile to get it flat is fairly simple and ensures that each tile is the exact same height as the tiles surrounding it.
Before I show you that you need to understand, as always, that the substrate preparation is the most important aspect of this. If your tile substrate looks like a skate park you’re never going to get a flat tile installation over the top of it. Your substrate needs to be as flat as you can possibly get it. Take time with your preparation – it makes the rest of the installation run smoothly and gives you a solid foundation.
Start by getting a few tiles set and make sure they are all flat with your straight-edge, just place the straight-edge on top of the set tiles and ensure that there are no open spaces beneath it and that every tile is the same height. You can push down on tiles that may be a bit high or take a tile up and place a little more thinset beneath it to raise it some. Once you have that correct the rest is cake, baby! (You ever seen a cake baby? They’re messy…)
All these photos are of a travertine tile bathroom floor. I used travertine photos because it happens to be one of the least dense stones and usually have quite a few pits and open spaces in the stone itself. If the tile is ‘filled’ travertine, as this is, it is normally only filled from the front so that, once installed, it has no open areas or pits on the face of the tile. You can, however, see these open areas in the back of the tile. I’m gonna show you how to fix this, too. You get a two for one with this post.
Photo 1
Once you have the initial couple of tiles set, as in photo 1, just comb your thinset onto your substrate in a uniform direction. (Make all the little lines from the trowel go the same way) This eliminates the possibility of trapping air beneath your tile and leaving spots that are not fully adhered (hollow spots). If you make the pretty little swirlies they may look cool, but they can also trap air beneath your tile. On a side note: my spell-check just told me that ‘swirlies’ isn’t a word – so I’m makin’ it one.
In photo 2 you can see the back of the travertine tile. See how it has all those pits and crevices and empty spots? You’ll want to fill those up with thinset to give the tile a good, solid fill and, essentially, make it more dense and durable. Do this by using the flat side of your trowel (Photo 3) and scraping thinset along the back of the tile in every direction. This ensures it is completely full and there are no open areas left. (Photo 4)
Photo 2
Photo 3
Photo 4
-This is what is called ‘backbuttering’ your tile. You’ll more than likely run into that term a lot when researching tile – that’s all it is. For an installation where you have an inconsistent tile or a questionable substrate you can always do this, then flip your trowel around and comb thinset on the tile as well (make pretty little lines – not swirlies!)
Now that you have a good solid piece of shiny rock to put down on your floor, flip it over and put it there. Make sure you flip it over – shiny side up. 
When you place it in the thinset on the floor place it directly against the two tiles adjacent to it (Photo 5) so that two sides of the tile are actually touching the two tiles next to it. As you do this you can push the tile down to just the right height to be flush with the tiles next to it.
Photo 5
This will ensure that the tile you just put down is the same height as the surrounding tiles. You can take your straight-edge again and use it to push the tile down and get it to the same height. If your tile goes down too far – PULL IT UP! and put a little bit more thinset beneath it.
I yelled ‘PULL IT UP’ because for some reason people think that once the tile is down – that’s it. It can’t be moved. That’s not it. Until the thinset cures – tomorrow! – that tile can be moved, pulled up, adjusted, smashed, replaced, etc. Do not be afraid to pull it back up and put more thinset beneath it if it sets too low.
Photo 6
After you get the tile at the proper height, and this needs to be along both edges that are touching, then you can go ahead and pull it away from the two tiles to create your grout line and make sure you are, indeed, at the proper height. (Photo 6)
Then just insert your spacers and make sure it is in the correct place. (Photo 7) Pulling it back also ensures that there is full coverage between the thinset and the back of your tile. Remember those little ridges that the trowel created? The ones that were not fully squished down as you were adjusting your tile will be pulled slightly as you create your grout line and this will create full coverage and support beneath your tile.
Photo 7
Photo 8
-You can take your straight-edge and lay it across the tile to ensure that they are all perfectly flat. (Photo 8 ) If one sets a little bit high you can simply wiggle the straight-edge back and forth until it is flush. If it sets a little too low – PULL IT UP! (damnit) and do it again.
It may seem like a tedious process – it is. But when done correctly you end up with a totally flat, professional looking tile installation which will last for years.
See: 
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HI Roger, great site so thanks for that
I’m installing 24″x24″ stone tile in a kitchen-Breakfast nook-pantry. I have already installed 1/4″ Hardi Backer(with fortified thin-set ofc).
Now the floor was wildly unlevel to start with (70yr old house) and the area includes mostly normal subfloor with an area of poured slab in the middle.(The slab part has a noticable crown in it) I’ll use a slc to minimize any hump but I’m trying to work within a certain height tolerance.
Since the floor is still not completely flat and I’m using the 24×24 tile will a meduim-bed mortar be the best way to work out the imperfections? I assume I can get more tile by tile adjustment out of that product coupled with 1/2×1/2 square trowel. Also should I be buttering the backs of all the tiles. I know it will take longer to do it that way but it will also help greatly with cracking will it not? Any suggestions will be greatly appreciated
Hi Jason,
Yes, a medium bed would be your best option. And yes, they absolutely need to be backbuttered. Just take your time, medium bed is great stuff once you get a feel for it.
Thanks Roger, Done with the 24×24 tile and it came out great with advice taken
Again, great site!
Thanks
Roger,
I find your knowledge and advice to be “spot-on” and very well explained. I admire your skills and expertise but I’m not clear on these points. P.S.(caught that?) My full bath will be a tub 5’…same question per the tub flange. Thank You,thank you very much !!! 
I just purchased your Kerdi Waterproofing manual and have a couple questions that have confused me (normal state of mind). I am installing a pre-fab shower pan in my smaller bath with a bench enclosed at either end with a small wingwall..frameless glass door set on the shower base.When I install the substrate should I cover the flange to within 1/4″ or hold it up to the top of the flange? Your illustrations seem to show the substrate up to the top of the flange? Second..you instruct me to BOTH fill my expansion gaps in substrate with silicone AND thinset? If I put silicone in them there will be no room for thinset..If I use thinset it will not “move”
Hi Ramon,
When using kerdi you should cover the flange with the substrate. Fill only the expansion gaps in the corner with silicone. The seams on the same wall (same plane) get filled with mud. You just need to keep thinset out of the gaps in the corners.
Hello Roger,
I am in the process of doing a little kitchen remodel. I took down a wall separating the kitchen and dining room and am building a cabinet peninsula there. The dining room has 3/4″ hardwood floor placed on the 3/4″ diagonal plank subfloor. The kitchen as the 3/4″ diagonal plank subfloor, 5/8″ plywood, 1/4″ linoleum (including it’s backer material), then they nailed 1/4″ backboard directly to the linoleum, and laid the tile with thinset. I have a hardwood flooring coming to lay some new wood flooring, placing it perpendicular to the existing wood flooring as a transition between the dining wood floor and the kitchen tile floor. I want to take this opportunity to retile the kitchen, as it is dated and I had to remove several tiles during the demo process. Given the multiple layers of the kitchen, there is almost a 3/4″ existing height difference between the two floors. My question is, is there anything I can do to bring the finished tile height of the kitchen down to match the wood flooring? I’ve read through the rest of the comments on this thread, and it looks like I’ll need to keep the 5/8″ plywood unfortunately. What I would like to do is remove everything down to the diagonal plank flooring and lay the cement board there then tile. Anything I can do to get that height down?
Thanks for the help, Matt.
Hi Matt,
You need to have an additional layer of plywood over the plank. Over that you can do 1/4″ backer or ditra if you need it lower than that.
Roger, I’m re-tiling my hearth over concrete slab. Previously it was a large piece of slate, simply resting on some 1/2″ drywall (also not adhered to the ground). I’ve cut and laid 1/4″ Hardie backer. Before I tile, should I use some sort of adhesive between the slab and the backer board? If so, what kind? I was hoping some sort of mortar or adhesive could give me an additional 1/8″ or less in additional height. Thanks!
Hi Mitchell,
Why are you putting down hardi? It shouldn’t be used over concrete, whatever you’re putting down for your hearth can just be bonded directly to the concrete.
Hi Roger
I bought 3 of your books and they are well worth the cost.
However they didn’ quite cover everything and I would like your opinion on what I am doing for a bathroom floor. The tile is 18″ carrerra marble and I already have 3/4 ply installed between the joists on sistered 2×4’s (glued & screwed to the joists). On top of this I was going to put 1/2 ply using screws (no glue or thinset), followed by 1/4 backer (using modified thinset & screws), then heat mat, self-levelling cement, DITRA (using un-modified thinset), then the tile (using modified or un-modified thinset). Do you think this will cause my dog to catch fire? He barks too much but I still wouldn’t want that.
Hi Ross,
You have 3/4″ ply BETWEEN the joists??? If so, that adds nothing to your floor, you still need 1 1/8″ above the joists. If you mean the ply is OVER the joists, your plan will work, but you have a lot of things going on there. All you really need is the double layer of ply, heat mat, ditra, then tile. You can use the slc over the wire under the ditra if you want (makes it easier), but there is no reason for the backer in that installation, it add nothing except height.
Thanks Roger
The reason I included the backerboard was because of this statement on the SunTouch website:
“Yes, SunTouch can be installed directly on plywood if it is covered with at least 3/8 inch of mortar. It is a good idea to coat the plywood with a primer that is compatible with your brand of polymer modified mortar. If you are installing a thinset tile floor over plywood, consider first putting down a layer of cement “backerboard”. Then, secure SunTouch to the backerboard and cover it with a latex or polymer modified mortar and then a finished tile or stone floor.”
Any comment? I’m guessing that the heating wire gets pretty hot and they want to keep it away from the plywood. However, I have put it directly on plywood in the past with no (known) problems.
I’ve never had any problem over wood. It’s always best to follow their thing, though, they don’t want the product to fail so they’ll tell you how to prevent that.
Thanks Roger
So no backer / SLC it is.
One last question – I used the next-gen durock instead of drywall around the shower and I am concerned about it’s flexibility in general and particularly around the cutout (approx 3″ x 9″) for the valve assy. The original durock was very solid and stiff but this stuff is very different. If I was using ceramic I wouldn’t be so concerned but it will be carrera marble. I am just about to do the kerdi so if I’m going to rip it out, now is the time. What do you think?
Hi Ross,
I think next-gen durock, with kerdi and tile over it will be more than strong enough to handle whatever you toss at it. They are made to be lighter, thus a bit less rigid, but once tiled they are completely solid. Hell, I install tile over FOAM every day – it’s not very rigid at first either.
Good point – thanks Roger
Roger,
Please help. My husband hired a day labor, an “experienced” day labor, to lay the hardie Backer on our kitchen floor. The kitchen floor is about 12×12 foot. The floor is tilted, the door side is about 1 and 1/2 inch lower than the other corner of the kitchen room. So the day labor just laid two layer of hardie board on the door corner, slop the top layer of hardie board over the first one, to try to make the floor more level. I am very concerned about the empty space under the second Hardie Backer, where the “step” down from the lower Hardie backer is. So he put a thin strip of wood there to soften the step down. I feel very uncomfortable about this practice. He also did not put down any thin set under the Hardie Backer.
I used a string to streched across the floor, holding down on each end by a floor tile. Looking the string across the 12 feet length, me estimate is that the maximum hight difference created by the slight dome of the floor is less than 1/4 of inch. So I think it would be better if we just use the original plywood floor, thin set, then one layer of Hardie Backer, should be fine. As you said, flat but not level. (This is a 100 year old house. A rental house, so we do not want to spend a lot of money to “level” the floor.)
However, my husband, somehow think the way the day labor did was good job. He thinks he made the floor more level. Am I right in thinking we will have less trouble down the road by just laying down one layer of the Hardie Backer properly, albeit a bit tilted, but flat? Am I right to say the day labor (and my hubby) was wrong to lay two layer of hardie Backer on one corner of the floor, creating a 1/4 step down at that corner, in order to attempt to level the floor without using SLC? (It is two guys against one women, you know.)
can you lay the tile on the same day that you lay down the Hardie backer board?
Yes.
Hi Yimin,
You are correct. Any unsupported space beneath your backer will lead to movement (wood under it or not), that will lead to cracking grout and/or tile. It would be better just to have one properly installed layer of backerboard. You can also level that one layer more than the floor with thinset beneath the lower corner more than the rest. As long as all of it is supported you’re fine.
Hey love the site thanks for the great info.
I’m installing 12×24 tile floors and walls. I’m using 1/4 x 1/4 x 3/8 trowel and backbuttering a thin coat and scrape off so that there’s about 1/32 of butter left. I find my tile sits out high. I was looking at the edge of my wall and the 3/8″ tile will sit at about 5/8″. Is there a way to minimize the “raise”?
By the way, I am pushing hard on it and it doesn’t seem to compress. I’m following the recommended water/thinset ratio. Would it hurt to add an extra cup or two of water to the thinset to make it a bit less stiff? I’m using Kiesel Servolight on the walls and it’s really thick and puffy!
It’s supposed to be that way, that means you’re getting a proper bond.
Hi Alex,
If you are using a bullnose then you can tilt it slightly. If you are just using the tile as the edge then there really isn’t. There needs to be a minimum amount of thinset behind it to get a proper bond. You can grout the space between the back of the tile and the wall, though.
Hi Roger,
I am about to install 12X18”, 3/8” thick porcelain tiles over Ditra-Heat and I am not what would be the proper trowel size. My floor is flat with a small region of minimal offset height making a couple of tiles to rock but so slightly.
Any advise would be appreciate and also how thick or fluid do I have to prepare my unmodified thin-set (Trio Supertech)?
Thank you
Hi Gerard,
A 5/16″ or larger trowel, whichever gives you the proper coverage. Your thinset should be about the consistency of creamy peanut butter.
We are laying a 1″ porcelain hexagon tile in our bathroom. It is not adhereing to the floor. We have tried an ultra thinset and versabond. We have used two different depth of trowel. Can you help??? We are pretty sure it is how we are applying the mastic, but if we make the layer thicker it squishes thru (as you mentioned in a previous response). If that is what is needed then ok, darndalarn, we will do it. Someone said we should back butter it, but same issue….
can you help, please
Hi Suzanne,
If you are actually using mastic, that’s your problem. You need to use thinset, not mastic for floors. The mastic will not cure correctly and has no compression strength, required on flooring installations.
Thank you for spending the time to make this site I found it the most informative on the web. I’m buildng a home and want to do the kitchen tile myself it’s a big kitchen 16×25 and I’m gonna lay big rectangular tiles and want it perfect, I have one lip in my kitchen now and it pisses me off every time I step barefoot on it. Anyways what are your thoughts on any of the leveling systems on the market??
Hi Nate,
I absolutely love, and regularly use, the MLT. They all work to some degree, but you’ll get what you pay for.
What is MLT exactly?
It stands for mechanical lippage tuning. More info here: MLT faqs
Sir, I plan to lay ceramic tile and the space is about 9 x 9. I have an old house and the sub floor is plank wood on a diagonal. It is not rotten, but very worn. I have screwed it to the floor joices, since it was only nailed, but am not sure if I can just thinset and hardibacker over it and lay the tile. Or do I need to put down plywood over it? How do I know for sure if it is flat enough? If I need to put down plywood, can I use 1/4 inch plywood as the floor will be getting high with 1/2″ of plywood/backerboard before the tile. Thank you and I might want to call you daddy before this is over, Jeanne
Hi Jeanne,
You need to put an additional layer of plywood over that. It needs to be 1/2″, not 1/4″. But you can do 1/2″ plywood, then put 1/4″ backer over it with thinset beneath it for your tile. A long straight-edge will tell you how flat your floor it.
I have just laid down a tile underlay floor in a bathroom prior to putting down my tiles. Now prior to putting down the underlay I new it was as good as I was going to get it as it was over a old timber floor. I have placed out the tiles and a few a rocking from corner to corner. If I use more tile adhesive on the low spots or gaps will this help to level them up?
Hope you can help
Hayden.
Hi Hayden,
Yes it will. If the amount of rocking is less than about 3/16″ then you can use regular thinset, if it is more you should be using a medium-bed mortar instead.
I am about to do a kitchen with 13×13 tile. If I use a 3/8 notched trowel what should be the finished height of the tile be, how much would you expect the tile to press down into the thinset? My previous job I seemed to have excessive thinset rise up in my grout joint causing me grief in the end. How can I eliminate this problem, thank you
Hi Al,
A 3/8 x 3/8 notched trowel will leave a 3/16″ layer of thinset beneath your tile. As a general rule just reduce the size of your trowel in half and you’ll have the height of the thinset bed. If you are having too much thinset rise through the grout lines then you’re using too large of a trowel.
I was just about to install 18″ tile over 3/4″ ply and 1/2″ backer, but I just read your advice about the need for 1 1/8 ply. Do I need to pull the backer up and add plywood, or can I put another layer of backer on top of what I have?
BTW, there will be a tile heating mat between the backer and the tile.
Hi Dan,
More backer won’t add anything except height. Backerboard adds no significant structural strength at all, it’s simply a proper substrate for tile bonding. Unless you do not have thinset beneath your backer (which means it’s installed incorrectly) I would not take it out. Taking it out with thinset beneath it will be more trouble than it’s worth. I would think about a membrane like ditra or strata-mat over your heating wires.
No thinset between the plywood and backer. There was going to be two thicknesses of 3/4 plywood, but the original floor wasn’t level, so there are some thin sleepers between the plywood layers. The backer is screwed to the upper layer, with the joints sealed with thinset, but not taped. I’ll probably break the backer if I take it up, but it’s only two pieces. Do it?
I would.
Roger – Two questions. If despite best efforts, you got some lippage, do you pull up the tile and start over ? Also, I have tried the regular thinset but are the pre-mixed buckets good, especially for decorative tiles ? [Main tiling done – I’m praying it sets fairly flat.] Again, thx in advance. Cheers !
Hey Claude,
It depends on the amount of lippage. If it’s a dime’s width then that is acceptable (mostly), if more it should be replaced. It really comes down to your personal preference – it’s your floor. I remove all lippage as much as humanly possible, because I’m not building my floors and showers, I’m building someone else’s. Pre-mixed ‘thinsets’ are not even thinset, they are mastic with sand added, they are good for nothing. Maybe a door stop.
I have a small bathroom in the basement I am attempting to tile using Ditra.
I understand what you say about flat not equal to level. That being said, the
Ditra is not uniformly flat – I attribute that to the concrete that the plumber used to relocate the drains for the toilet and the shower and my attempt to lay the Ditra without lawn roller :-}. Query, should I remove the Ditra and start over or give a try anyway and hope that lippage will be minimal ? Thx in advance.
Hi Claude,
It depends on how much those areas stick up. If more than 1/8″ or so I would cut the ditra out around them, remove the concrete to nearly level, and install ditra over it. The flatter you begin the flatter you’ll end.
Thx mucho – Would a tile leveling system like QEP (plus a spacer) work with Ditra to level things out ??? Or am I suggesting overkill ??? Thx again in advance.
BTW, Roger, I bought your book – p. 51 sounds like a great tip but
how do you stick Ditra to Ditra for the accent tiles ? Again, thx in advance !!!
Hi Claude,
With thinset. Just like you are bonding it to backerboard.
It’ll work just fine, but your thumbs will be worn out at the end of the day.
Hi Roger,
My GC tiled our shower floor with 2″ mosaic tiles and they are not flat. Seems like common sense to level the tiles with a straight edge but when I asked how he installed the tiles, he told me he used his hands. Is using a straight edge a basic tiling concept that all GC’s should do? Are there any tiling standards (we live in Fremont, California)? He wants me to pay more money for demo of the uneven tile and re-installation. I think he was careless and he should take responsibility. Please share your thoughts.
Thanks in advance,
Will
Hi Will,
It is standard procedure to get flat tile. How one goes about that varies wildly. I can get flat tile with just my hands, but that’s experience and it’s more difficult. If it is not flat it is a poor installation. Unfortunately there really are no ‘codes’ that must be followed unless it is done specifically through your local building department. You’d need to contact them to find out what constitutes an unacceptable installation.
Hi Roger,
I am so glad I just found your site, thank you for all the useful information.
I have pulled the carpet out of our family room, I cant tell you yet whats underneath the plywood (if thats plywood, it looks like little strips of wood) i.e. joist distance etc, I cant recall the proper terms you used, but I can tell you for sure that the contractor used materials build to minimum code only, nothing extra.
I have wood floors right beside it and I want to install porcelain flooring in the family room so I need to have the porcelain at the same height as the hard wood floor. After reading your web site, I am coming to the conclusion that I simply cannot use backerboard unless I am Ok with a height difference which I am not, so all of this to ask about Ditra, I understand from what I have been told that I can use a Ditra membrane and this will ensure that my tiles will not crack and that by using Ditra I dont have to worry about the subfloor does this sound correct? Its a very expensive product so I want to be 100 percent sure that it works
Your advise is greatly apreciated.
Thank you
Amy
L Pollution
Musique
Hi Amy,
It does work as intended. However, you still need a proper subfloor beneath it, which would constitute 1 1/4″ (3.2cm) thick double layer of plywood beneath it, with the proper framing. If it is minimum it has the proper framing, but likely doesn’t have the double layer. It will minimize the height difference for you.
I have a room / bar, 11 x 19, with 3/4 T&G subfloor over 2 x 8, 16 on center joists, suspended but every 4 feet or so there is a half inch redwood wedge against the slab. I’m about to install thinset, Ditra Heat, thinset and 4 x 32 travertine plank. I’d love to install with no grout line, but my friend says I have to have a 16th at least. At the tile store party, a guy gave me a package of his new diamond leveling spacers, a little circle with cross inside and wedges, and flat squares with toothpick like handles to pull up on. He was demonstrating it. I’m going to use our best outdoor patio mason, his helper and myself to do the job. What about the spacing and cracking? Cyn
What about it?
You NEED grout lines, period. I don’t understand what a half inch of redwood wedged against the slab is? Properly built you will have no cracking, what cracking are you referring to?
Our contractor just tore out 50-year old tile in our bathroom and replaced it with larger, 12×18 (approx.) tiles. It is not level by 1/8-1/4″ of an inch. It is flat, though. Big deal or or major impact?
Hi Suz,
It’s done correctly. As long as it’s flat that is sometimes all you can do. For instance, if the floor at the doorway were 1/4″ lower than the back of the room, leveling it will require raising the floor another 1/4″ at the door, causing problems with the transition into the next room. As long as it is flat it is correct.
Roger,
I just had my master bath tiled with 18×18 tiles. There was a heating element installed with a thin-set mortar before the tile was added. The tiles are not flush in many parts of the bathroom and I am wondering if this is to be expected or not. Thank you.
Alicia
Hi Alicia,
Absolutely NOT! It sounds like you had a contractor who had no idea how to correctly install tile over heating. It is not proper, and it needs to be redone. Your floor tile should be absolutely flat, no matter what you have beneath it.
Roger,
I am getting ready to lay down marble hexagon tiles, a bunch attached to a mesh. During subfloor prep I encapsulated radiant heating into Self Leveling cement. Unfortunately the concrete is not flat. Do I need to pour more to flatten it, or can I fill the gaps with thinset and level it using your approach here.
Thanks
Hi Yev,
You can use this technique with mosaics, but it’s a huge pain in the ass (you’ll have thinset squirting through the grout lines). I would level it out with slc or thinset to get it flat first, it’ll be MUCH easier.
Good day,
We had a honed travertine floor installed using a schluter system in the bathroom and there are areas where stones meet but they are not level to each other. The worst areas are maybe a couple finger nails thick where the butt up to each other. The GC says that is the beauty of stone, I think they took a short cut. We paid well for the job. When there is unevenness like this can they sand/grind to smooth the variance going from a low to high grit? If so would this be part of a normal installation? Might we be more disappointed after this type of fix?
Thanks, Steve
Hi Steve,
With a honed travertine the tile should be flat and flush with one another. It’s called lippage, and while there’s an acceptable amount, it’s normally less than the height of a dime. It can be sanded down and finished but to get a professional job on it you need to hire a professional to do it. If not done correctly it will definitely look worse than it currently does.
Roger,
I am tiling my floor with 13 in square tiles. I applied 1/4 in hardibacker over a wood subfloor per your instructions, taped and all. I was checking out the level of the floor and I noticed that when I “dry laid” out my tiles over the floor, there were a few tiles which are “rocking”, creating about 1/4 in “lippage” if I make one side of the tile perfect with an adjacent tile and then measure the height difference on the opposite tile.
I think that the root cause may be that I applied a small amount of extra thinset over the seams. (Although, the build up is only about 1/16 of an inch on the seams.) Anothe possibility is that I also had replaced a plywood sheet in this area before installing the haridbacker and it was not exactly the same thickness as the extsting ply (but off by a very small amount, like 1/32 of an inch).
My question is whether or not the tiling technique that you recommend can compensate for this 1/4 in of potential lippage. Or should I resort to something more dramatic like a self leveling cement.
Hi Jim,
I just answered your question where you asked it the first time.
Yes, you can make up for that with this technique.
First of all, excellent advice on this site! A couple questions for a major tiling job I’m embarking on. We purchased a foreclosure which has 24×24 honed and filled travertine in the living room. Several tiles are cracked (I suspect because installer did not put cement board over the plywood substrate before tiling) and we are going to dig them out & replace them. This size is very difficult to find and may end up going to Miami to ferret some out. We want to tile the bedrooms in 18×18 travertine and want to do it right. I’ve read a 1/2 cement board is appropriate over the plywood floors in the bedroom but what if the height of the backer board and 1/2 travertine creates a lip between the new tile and old at the transition point? How to handle? Can I use 1/4 backer board or is 1/2 the way to go?
Hi Dawn,
Transitions always need to be made. NEVER compromise a tile installation because of a transition. You can use 1/4″ backer on a floor provided you have thinset under it (as well as under 1/2″, should you choose that). However, the floor substrate itself requires a double layer of plywood above the joists with a minimum thickness of 1 1/8″. You can not go over a single layer with backer and not get cracking. Your cracking problem is likely either no second layer of ply, no backer, or, if he installed backer, I can nearly guarantee that there is no thinset beneath it.