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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Roger
I think ur site is pretty bad ass! Very helpful too. I read through the comments and realized I should have taken more time on the subfloor! Well I have a mini skate park in the middle! I do all our remodels around the house and my wife is always amazed with the finished product. I would like to keep it that way. Just wondering how I should go about this floor. Should I just do it by adding thin set where needed and tie a straight edge to my hip? Or should I tell you where I live so you can come over and put a boot in my ass? Plz help, and thank you!!!!
Hey Jeremy,
The easiest way is to use a layer of cement board (I assume you’re doing this – RIGHT?!?) and place it on the floor with thinset beneath it as such that it gives you a flat floor (i.e. more thinset in the middle of the floor). Then let it cure, then screw down the backerboard. This should give you a nice, flat floor before you begin tiling.
And yes, tie a straight-edge to your hip anyway.
Hi Roger,
HELP! I think, Well, I know I have a major problem. I pulled a piece of granite tile that I set last night (12×12) figuring the thinset would still be green and if I ruined the piece of tile so be it. I had used 1/2 hardiebacker placed in thinset and screwed every 6 inches. (Yes I used the proper screws). The backerboard seperated at about a perfect 1/8 inch layer where it looks like it was layered together in it’s making. I started looking around all outer sides of the backerboard that are visible and notice light seperation at about the 1/8 inch layer. I can spring the layer up and down with just one finger. These areas have never had tile set there yet either. Is this batch of hardiebacker defective or did I do something wrong? With this movement between layers I am thinking it best to tear out everything done so far. I look forward to your opinion.
Thanks again,
Steve
Hey Roger,
One more thing, I just noticed that the seperation of the layers seems to start where each screw went through. Like the screw threads seperated the layers as they went through. Is this common or normal?.
Thank you again,
Steve
Hey Steve,
As the screws penetrate layered boards it may indeed separate the layers just a bit as you are screwing it in. However!, as you fully sink the screw it will stop the separation in short order. If it is migrating out from that area it is either that the screws are not fully countersunk or the lamination of the backer is delaminating – which would be a problem with the product.
Check the areas right next to the screw heads. Are they solid? In other words, could you screw them in more if you tried? If it is solid around the screws and still coming apart away from those areas you would be better off contacting the hardi representative and explaining the problem and see what needs to be done.
Hey Roger,
Thanks for the quick reply. I think I will contact the rep. The screws are definitly fully countersunk and the seperation goes from 3-4 inches beyond each side of the screw heads ( puckered up). With my hand, I pulled a layer off 12 x 18 roughly right through the screw heads with little effort. I’ll see what they say. I ran into some delamination problems very occasionally with other products through my several years installing vinyl, looks simaliar. Just to make a comment about your work. I was asked by several flooring companies I installed for that I should think about doing tile as well. I always said no. I admit, It is an interesting profession. A lot to learn no doubt. It is more than just installation, It is artistic. From some of the pictures I have seen of your work, You are really a master in your craft. Your work is a pleasure to see.
I just want to say thanks again for all the help you have been.
Steve
Thank you Steve, I appreciate that.
The rep should be able to point you in the right direction. If you would, please let me know what you find out. I like to always add information to my ever-expanding list of useless knowledge. (It’s all useless knowledge until you need it :D)
Hi Roger,
To give you an update on the Hardiebacker. Actually I just pulled up the separating 1/8 over the entire job, Did it in about 8 min’s. The only places that gave slight resistance was at the screws, Still not that hard to pull it up. It peeled perfectly flat and smooth leaving about a perfect 3/8 still bonded.
I called Hardiebacker 800# and spoke with customer service. They transferred me to tech support and when I told him what was happening, His words were, I should not be able to do that at all, This absolutely should not happen with their product. He then transferred me to their claim dept to which they are going to e-mail me the claim info. Sounds as they will stand behind their product so far. I will let you know the outcome and just how much of the job they will cover. Especially as the job is half complete and it is separating the bonded pieces at the 1/8 depth. Hey, There’s a new concept. Granite tile pre-layered with 1/8 backerboard already attached.
Thanks for the update Steve. In my experience hardi has always stood behind their products. Sounds as if this is no exception.
I’m still working on self-installing granite myself.
Good evening Roger,
It’s Steve again, by now you must be getting tired of hearing from me.
As for the delamination with the hardiebacker. I just finished removing the entire 1/8 inch layer across the surface of the entire job. As I have stated it is leaving a perfectly flat approximate 3/8 of an inch. I removed all the screws which of course were sticking up. The 3/8 remaining is bonded to the three-quarter inch plywood with the versabond thinset. This time I was just going to use just standard cement board. So my question is this. Am I able to bond with thinset, the quarter-inch cement board to the remaining 3/8 hardiebacker? If so, what is your preferred method to attach the cement board, galvanized roofing nails or screws. Also, where I have removed the screws from the remaining 3/8, should I reset the screws in the existing holes, of course counter sinking them first.
Thanks again,
Steve
Yeah, you can go over that with more thinset and cement board. The problem I would have with it is we don’t know how stable the lamination between the remaining layers is. If you think it’s nice and solid then you can go over it with the new stuff. No need to worry about the screw holes, the thinset for the new layer will fill them and the screws will hold it down.
I would make sure you talk with the rep and ask his opinion on that before going ahead with it, though. He would know better than I what caused the problem to begin with and the best solution going forward.
Hi Roger,
I am setting tiles perfectly flat and wow, What a pain to do. As I slide it over to the other, It moves ever so slightly. Then have to realign them both. Is there something I am doing wrong? Or do you have any tips? I have had to push down on some of the tiles to get them perfectly matched. Is it possible to push the tile down to far. I have some areas that are 1/8 inch, maybe even just less of thinset under the tile. Is this going to be a problem? I am using Flexbond as my thinset. If so, What do you suggest? Should I tear them out and use 1/2 notch instead of 3/8?
Thanks,
Steve
Hey Steve,
Nope, you’re doing fine. It’s simply a pain in the ass.
When you put down the tile put it down right against the one that’s already down and slide it AWAY from that one. That should eliminate most of the movement. 1/8″ thinset beneath it is not a problem. The thinnest allowable is 3/32″ so you’re just fine. Trowels fine too. It is possible to push it down too far, if you need to raise it, pull it up and put more thinset under it. Just take your time.
In short – you’re fine.
It’s just difficult to get completely flat tile. Welcome to my world. 
Hi Roger:
We are prepping the floor in the bathroom, and where the old vanity used to be, there is the old felt backing from the original vinyl tiles that is stuck and won’t scrape off. It is level with the rest of the floor, but David wanted to know if it would fine to tile over it? If not, we will have to figure out how to remove it. All the old thinset from the previous 2×2 blue floor is coming off, but the square of felt is not budging.
Sorry, it was old linoleum tiles.
Hey Jane,
That’s called cutback – and it’s a pain in the ass. It needs to be removed and to be honest the best way I’ve found is by soaking it with water and scraping it. Thinset will not bond to it long-term.
David says you’re a genius. The stuff came right up!
How much space should I leave between the tub and the floor tile? Here in Maryland, we had a 5.6 earthquake last summer which cracked the 45 year old ceramic floors in all 3 of my baths. I am retiling with porcelain and doing a 3/8″ gap at the walls and have caulk to match the grout. Should it be 3/8″ at the tub too? The new tub is metal but only weighs half as much as the old one. Should I use bathroom caulk at the tub-floor joint or the color matching? Thanks- Love your site. Much more fun than jb. You should write a book with all those pictures.
Hi Nancy,
I would use a 1/8″ – 3/16″ gap at the tub and use the color matched silicone or caulk.
What do you think of using glass mosaic tile as an accent strip on the floor?
Hey Eileen,
As long as the glass is approved for floor installation it’s fine. Check with the manufacturer to see whether you can use it on a floor or not.
Hello Roger,
I have a question regarding the sealing of Travertine tile. Do I need to pre-seal tiles before installing?
I have read on some sights that washing and pre-sealing is required to avoid staining with thinset and grout while installing.
Thanks,
Sabino
Hey Sabino,
It is not required, but it is a good idea to seal it before you grout. No need to seal it before installation. If you are installing lighter travertine you need to use white thinset – it will not stain your travertine. Sealing before grouting makes it easier to clean up.
Thank you Roger,
Really appreciate your feed back great site.
Have another favor to ask of your expertise, I was told by the sales person that the travertine does not require any spacers and that when grouting the grout does manage to slip through joints enough to seal. I would imagine that at least 1/8″ gap would be favorable to assure even sealing against moisture, what’s your take on the matter.
Duh! just ready your post…
“Can I Install Tile Without Grout?”
what kind of spacers would you recommend.
I prefer horseshoe or ‘marble’ spacers. They don’t crush.
Hi Roger,
After installing the floor tile in my new shower ( 12″ mosaic, Herringbone pattern) I have several areas that I need to remove the tile and correct for level underneath. These areas are around the perimeter where the Kerdi membrane overlaps.( In a couple of places I have three plys of Kerdi membrene)
How to remove the tile without destroying the Kerdi membrane and/or the Kerdi shower pan??
Your help is appreciated.
Lloyd
Hi Lloyd,
Unfortunately you cannot really remove tile from kerdi without destroying the kerdi. The best way to try is to twist the individual tile back and forth to try and debond it or smash the tile into little pieces with a hammer and remove the small pieces carefully.
Does anything comes between the cement board and the thinset what holds the tiles?
As I understand the layers are
1. whatever is on the hard floor (I could leave the vynil tiles on?)
2. Thinset
3. Cement backerboard
4. Thinset
5. Tile
What is travertine tile?
Hi Rekamimi,
No, nothing else is placed between the thinset and cement board unless you are waterproofing it with a membrane such as redgard. You can leave the vinyl tiles on, but it’s better to remove them if you can.
Travertine is a natural stone which is formed from hardened mineral deposits that are left over after carbon dioxide-rich water filters through rocks and earth. As the water passes through areas with concentrations of limestone, the limestone dissolves. When this limestone saturated water reaches the surface, the carbon dioxide is released due to the changes in temperature and pressure. As the carbon dioxide fizzes out of the water, the limestone is left behind, and re-crystallizes over underwater plants. As these mineral deposits harden into stone, they can be made into tiles. Travertine tiles are characterized by fissures and small irregular holes on the surface of the tile that are not found in limestone. That answer your question?
This is one of the best pieces of tiling advice I’ve seen. What’s missing from other information I’ve seen online is anything that (a) even refers to the existence of non-flat floors in the universe; and (b) what should be done about it.
For me it confirms what I believed would be the ideal approach. It’s good to read expert confirmation. What I believed to be a sound way forward comes from experience of doing numerous ambitious DIY projects, including tiling. I’m about to commence only my second tiled floor and this one is BIG so I felt it important to validate my method. Thanks.
I’d add this advice for when tiling in stages, such as when you let the central part dry and continue tiling later, or when the cut edge tles are laid after the rest are set:-
* Beware of your adhesive/thinset being moist enough to be pressed down under a heavy tile so it oozes out and the tile droops while you’re away! Either the adhesive/thinset needs to be firm enough or we need – I suppose – a temporary wooden guide weighted down to fence things in.
Hey Dave,
You are correct, that is a concern. However, if sufficiently heave a medium-bed mortar should be used to set it rather than a regular thinset.
A few days ago, I installed Ditra for a porcelain tile floor. The Ditra came out wavy leaving random high and low spots across the floor; I expect I had too much thin-set under parts of the Ditra. Arg!
I dry laid all full tiles (25 of 43 tiles). Most sit ok, a few rock due to low spots, and 2 rock a lot more due to high spots. An 8’ level shows most low spots are < 7/64”. A few places along the tub are ~9/64” low, and one corner of the room which is covered by a hamper is low by ~3/16”.
I’ve thought about starting with the tile on the one high spot with the most rock, and then matching that height with all other tiles. But this seems extremely difficult to successfully do, especially for a first timer. And this might not be the highest spot in the room, just the perceived one due to the tile rock.
I’ve thought about using thin-set to fill in the Ditra waffles and even out the wavy floor the day before installing the tile. But a straight edge used to screed the thin-set an even height will just ride up and down the high spots. The deviations are small, but enough to effect tile lippage.
Is there a way to recover from my screw-up without ripping out the Ditra (and thin-set), and starting over?
Thanks.
Hi JD,
You can either start at the highest spot and work out from there, use a larger trowel (1/2″ x 1/2″) to compensate for height differences, or pour self-leveling cement over the ditra. The SLC would be the easiest option and won’t negate any of the properties of the membrane or uncoupling properties.
Roger,
Another element has been introduced to my dilemma, the “expert” at the big box store (HD) just told me I needed to also tape the joints of the cement board!!!!!
Slab, ceramic tile, PL200 adhesive, joists, more PL200, 3/4″ plywood screwed and glued to the joists.
Now :
15# felt
thinset
cement board
screw down immediately after setting, but not to the joists
then tape joints?????????????
set tile
Is this correct?
Ron
Yes, that is correct. The felt, or barrier (cleavage membrane) normally is installed beneath the plywood between the ply and concrete, but as long as it is in the assembly beneath the tile you’ll be fine.
“The thinset is only to support the backer fully – it doesn’t need to stick to anything. It’s only a solid bed for your backer.”
Roger,
I am thoroughly confused now, the manufacturer’s installation instructions( and your advice) are to screw the cement board every 8″ in both directions and around it’s perimeter. If ” it doesn’t need to stick to anything.”, why screw it down? Also, if I do screw it down I will pierce the vapor barrier many, many times.
The thinset doesn’t need to stick to anything. The backerboard does need to be screwed into the floor. Follow the every 8″ in every direction and 6 around the perimeter. The thinset only supports the backer fully so there are no voids once it’s screwed down. If you read through this: Installing backerboard for floor tile it will answer most of the questions both you and George are asking.
By the way,
we always put 15 lb. felt on top of the plywood before putting down the substrate (particle board.) On this job, we plan cement board on top of the 3/4 inch plywood. I feel the felt is necessary, how about you???
Hey George,
The second (or third) layer of anything, plywood or cement board, should never be screwed into the joists if tile is to be installed. If it is screwed into the joists you simply have a very thick subfloor. If, however, it is screwed into the first layer only it will allow the second layer to act as a buffer of sorts. If not screwed to the joists any direct pressure from the joists to the bottom of the subfloor is distributed over a wider area rather than simply placing point pressure directly above the joists.
Some guys are more comfortable with grids or chalk lines, some are better with spacers. It really doesn’t make a difference how you get to the end product with straight lines – only that they’re straight. They both work very well if used correctly – the spacers take a hell of a lot of practice to utilize effectively. Chalk lines are much easier and accurate in most situations.
If you have no vapor protection beneath the single layer and joists to stop moisture then yes, you should have a barrier (the roofing felt) somewhere in the assembly beneath the tile. You will still need to install thinset beneath the backerboard to fully support it, but you can still put down felt first. The thinset is only to support the backer fully – it doesn’t need to stick to anything. It’s only a solid bed for your backer.
OK Roger, I hear you about not screwing the cement board to the joists. I had thought it would cause an indention if you did, so it makes sense to not pull it down too tight thereby creating a flatter surface. One might even make sure not to hit a joist, even though I doubt 3/4 inch plywood will have an indention.
@ Ron, I don’t think the moisture barrier is supposed to be totally water tight, even though the screws will be pretty pretty tight. The issue I always heard is that wood sucks moisture out of cement, concrete, block etc. I doubt there is much moisture in the cement board, and I doubt the homeowner will ever flood the floor. But at least the moisture barrier will separate cement and wood which is just second nature for us wood chucks.
I bet Ron’s job will survive the rest of the house
That is correct. The barrier is not for waterproofing purposes. When you have sleepers over concrete you create a vapor differential which causes the moisture to normally escape into the wood. With the barrier in place it does not continue into the wood as much and the wood will not prematurely suck moisture out of the thinset. When building sleepers over concrete it is best to have the barrier beneath the wooden substrate, but it works above it as well. The barrier is in place only to handle vapor differentials – which cause more problems than most people are aware of.
Roger
To make it a perfect job, it appears one would need a vapor barrier below and above the plywood?
geo
Ideally the vapor barrier should be placed between the concrete and any wood or wooden substrate above it. Vapor will dissipate from the concrete – always. The sooner you can stop it the better. Placing it above the plywood does not prevent vapor from entering the wood, it will, however, manage the vapor variance above and below the assembly preventing continuous absorption.
I’m the framer helping Ron. Never heard someone say to put the cement board down and NOT screw/nail it to the joists (sleepers) before. Of course I never put down cement board before either. I have put down particle board for carpet and linoleum.
I totally understand the tiles not being “completely square.” Even though I never did tile, I would think as with Shingles (which vary from 35 15/16″ – 36 1/16″) that Chalk Lines, NOT spacers, would be the better way to get straight grout lines. Many roofers chalk the first line and then simply “eyeball” the rest of the water lines to make sure it looks straight. Point being, spacers could cause a gain or loss and so straight edges and chalk or string lines along with eyeballing the job should help keep everything looking nice and straight.
I have just enclosed a previous screen porch, floor was 12×12 ceramic tile over concrete slab with a 2″ slope in 11’6″ run( area is 11’6″x 22′). I ripped 2×8 PT, set on 16″ centers, used PL200 adhesive on top and bottom of 2×8’s laid 3/4″ plywood over that, nailed with galvanized ring shank nails on 6″ centers. I now have a nice, solid, flat floor. From some previous advice of your’s, I will now cover that with cement board before setting 18×18 travertine. After searching, not for long, for your recommended method, I decided to just ask again. What is the best method of attaching the cement board? Also, a previous installation in this same house has 18×18 travertine set tightly abutting each other, no grout lines, is this typical ?
Thanks again, Ron
Hey Ron,
Offset the seams of the backer and plywood and use backer-specific screws to attach it only to the plywood layer – not to the sleepers you’ve installed. Of course you’ll want thinset between the backer and the plywood to fully support it. No tile should be installed butted to one another. Read through this and it will explain why. No grout lines
Hi, just found your website today and have read a lot. Thanks for doing this! I’ve found it nearly impossible to find good info on tiling as there are so many people offering opinions.
I’m attempting my first tile job and here are the details: subfloor is 1×6’s, 3/4″ t-n-g OSB board screwed on top (avoided the joists). I have concrete board fit in but not screwed down yet. When I check for flatness, I have a 1/4″ to 3/4″ bowl shape where the edges of the room are higher and it dips toward the middle. I bought some self leveling stuff to hopefully fix this problem. So here are my questions:
1) am I good so far!?
2) do I pour the self leveler on the OSB, or do I put the concrete board down, prime it, then pour SLC on top of that?
Thank you so much for taking the time to help out!
Hey Danny,
You’re fine so far, except for that whole ‘bowl shaped’ thing.
You want to install the concrete board with thinset beneath it first, then prime and pour your SLC. You don’t want to install the SLC then screw through it. And I don’t know if the primer will work on OSB – I never thought to ask. 
awesome – thanks for the help!
Hi Roger,
I’ve got a 3/16″ V-notch trowel worth of thinset curing beneath a sheet of 1/4″ Durock. Something doesn’t seem right. When I dry fit the tile, I’ve got 3/16 of an inch more height to match the 3/4″ hardwood. I had originally divided each trowel I planned on using (3/16 V-notch below, and 1/4×3/8 above Durock) by 2 to get final thinset heights added into the tile (5/16) and durock (1/4) thicknesses. The math I did said the two surfaces would be a match, if not a fuzz taller tile. Can I get the two to match with thinset, or do I need to tear out and rebuild with thicker materials?
Thanks.
You can build up most thinsets about 3/8″. A v-notch trowel will leave about 1/3 of the notch height rather than half. That’s where at least part of your height difference came from. Just build it up to what you need to meet the wood.
Cool thanks. That’s a life saver – from the wife.
i have another question now. The doorway where the hardwood is is on the left of a 5×6 room. To get the tile to match the hardwood, would you start with at least one tile at the door, then work counter clockwise into the room and make your way over to the opposite corner, then back? Or do you find it easier to scribe a level line on the wall of such a tight space?
Thanks.
One more question. The dimensions of the room vs tile will leave a thin rip of tile somewhere. In this situation do you find it better looking and easier to make 2 larger, but equal rips that installs at the base of opposing walls? Or do you just put the thin rip along the wall opposite the door?
Thanks again.
Actually neither one, I dry-fit tile from the doorway back into the room to about 3 feet from the wall then start setting at the back of the room and work my way out. This way you aren’t missing the measurements by 1/32″ and end up 1/8″ or more off in the doorway.
Always make equal rips down larger tiles – small slivers of tile look like crap.
Very helpful. Thanks. I didn’t think of that issue. How about the height match by the time I get back to the door/hardwood floor? Wait a sec, I could shim the dry fit tiles by the door for height, then straight edge across the room to those, huh? Dang, tiling sure is detail-oriented. Makes one appreciate a quality contractor more.
Yup, you nailed it. Why you buggin’ me???
I’m just kidding. And yes, it is very detail-oriented, but only for the ones that care.
Thanks mang. (Please excuse reference to Sandler. I just felt like saying that. It’s the weekend good mood thing I guess.)
That was my point. It’s rare and appreciated. Nice work.
Hello again, Roger.
Hey, on a different thread I mentioned a project wherein we’re installing a bathroom floor on a concrete slab, on grade. Although the entire floor tilts east a fraction only perceptible to liquids or those who have consumed too much liquid while worrying over the constant danger of lippage, it’s perfectly flat and pretty well “tile ready.” Seeing this boon, it was mandatory to complicate the situation with feature creep.
“We” (that would be the “me” of “we”) have equipped this floor with Suntouch heat mat in selected portions of the bathroom. After pre-embedding the Suntouch mat in thinset prior to setting tile according to the most Old Testament and conservative version of the Suntouch installation instructions, a couple of things immediately struck me with fear and loathing.
First and least important is that adding the Suntouch mat is going to mean mixing up probably at least another bag of mortar in order to bring the rest of the 85 sq. foot floor up the 1/8th” and a skosh the mat adds.
However, what’s got me really bugged about this is that while I realize I should probably start laying tile in the area with the Suntouch mat so as to establish that as my tile altitude control, there are some tile joint lines on the already-built shower curb that I’m planning on matching up with the floor lines, on both the “X” and “Y” directions. Theses lines are somewhat remote from the Suntouch zone, and so I’m wondering how I can make absolutely positively sure that these lines end up properly aligned with the floor lines when all is said and done.
I’ve got a 3-tile grid laid out on the floor and am using spacers so theoretically everything will work out, but I’m acutely aware of the wide and frequently insurmountable gap between the theories floating around in my head and the often oafish product of my hands.
What I’m wondering is whether I could stretch a level line across the room and start laying tile in the location of the curb, aiming to maintain target height as I reach the region of Suntouch dominance. Is this a legitimate technique, and is it likely to work at the hands of a rank DIY HO?
Maybe I should just order up a truck full of leveling compound and bring a hose in through the window??
BTW, on the earlier thread I’d mentioned setting up a thermal break between the slab and the Suntouch mat. Based on your advice I switched to 12″ tile so as to avoid stability problems, ended up using Custom’s “EZ Mat” underlayment for the thermal isolation. It’s great stuff for this particular requirement, makes the floor notably more comfortable even without heat. Though it’s truly “EZ” I doubt it’s actually 4 times faster to install for anybody used to dealing w/Hardibacker or the like, but that said seems very well suited for this niche application.
Hey Doug,
If you have your grid in there and it’s lined up with the tiles on the curb, provided your grid is accurate you should be able to start at the highest point on top of the heating wire. Find the highest point and snap a couple more lines so you have a two tile wide grid at least from that point to the tiles on the curb. Then stay right on that line beginning at the highest point. I wouldn’t start at the lower point guessing it’ll line up – I’ll always start at the highest point. It guarantees proper height. You can also dry set the tile in there without thinset first to ensure your curb lines up. Once they’re in the right spot then start putting down your mortar and setting them.
EZ mat is great stuff for certain applications. A thermal break is definitely one of them!
Thank you, Roger. I found the summit as you suggested, have set a control group of tiles in that area. Looks as though everything will now line up!
Setting the initial group of tiles also made me realize that trading some dollars for patience and skill is the way to go here; I’m going to cheat with leveling compound to get the remainder of the floor a little closer to the top of the mat+thinset zone. I had some panicky moments with my level when I realized how wavy the top of the mat is and what a slope there is heading down to the unheated portion of the floor. There’s only so much a neophyte can accomplish with a slotted trowel.
Gravitation and goo is our friend here!
Thank you Rodger, I checked, it was the blade, cuts with a new one are perfect. One more thing, if I may. My last project was tile on a concrete subfloor. The grid lines I snapped, and sprayed with hair spray to keep from rubbing away, disappeared under the thinset. I couldn’t see them at all -on cement board I can see them through the towel notches. I was forced to pull string lines over the top of the tile to align them. What do the big boys do to make their grid lines visible on concrete through the thinset, or is there something else I should know? Lloyd
Hey Lloyd,
Unless you are using a membrane which utilizes a mechanical fastening rather than a chemical one (like ditra) never spray hair spray or laquer or anything else on your substrate to save the lines – the thinset may not fully bond. These are known as bond-breakers and may lead to your tile not being fully adhered to the substrate.
When I first started snapping lines I would simply comb my thinset right up to the line so I could barely see it (you still need full coverage – don’t hold the thinset back simply to see the lines). I now use an ink line rather than a chalk line. These are just like chalk lines but leave a thinner, cleaner line with ink and once dried they don’t rub off.
Roger, thanks for the page and info. I have laid ceramic tile on four different floors in two different homes a still struggle with getting the flat professional look I want. I will try your tips on an upcoming bathroom. I have two questions. How do you pick up a poorly laid tile? I have pried with my fingers, used a broad knife to cut under it and pried up, and even tried a flat bar but I have never gotten one up…without damage. How do you do it? Two, my wet saw cuts ceramic tile well but chips porcelain tile. The few cuts I can’t hide with trim -at the threshold and base of the tub, are too chipped to use. What can I do to get a chip-free cut? Lloyd
Hey Lloyd,
Get your fingers under one edge and push the tile toward your fingers. You want to lift that edge as you slide the tile. The slide and lift is the easiest way to get them up.
It’s likely not your saw – it’s your blade. Porcelain is much harder than ceramic. A regular ceramic blade (probably what you have on there now) will chip your porcelain. Get a porcelain blade and it should leave a nice, clean cut.
Roger….
I sent comments on how important your Elf Tips have been to us, and hoping you can think of a lot more to send us.
I’m going to start working on our shower pan. Right now I have a normal shower drain; a concrete floor. Question is: can I use a quick – pitch shower floor drainage kit. Put the rubber membrane over the pre-slope than use another drain kit for proper slope when I put the deck mud, then tile.
The pre-slope will be flush with the drain base. The membrane will cover the drain base. Question: when I bolt down the clamping ring, do I have to put caulking around the bolt holes, so water won’t go through. Next question: can I use a positive weep hole protector under the finale deck mud. I hope this isn’t another one of my dumb questions.
Hi Marty,
And I sent you back an email with answers. Apparently your spam filter is on a shooting rampage.
You can use a positive weep hole protector above the liner beneath your final mud deck. No silicone in the bolt holes. They are a closed thread in the bottom flange so if any water does get in there (it won’t) it’s not gonna go anywhere. You do want silicone BENEATH your liner between the liner and bottom flange all the way around the drain.
You can use the quick pitch for your pre-slope – but that’s it. If you use another quick pitch on the top deck your overall slope will end up at 1/2″ / ft. Your top mud deck should be a consistent thickness throughout – from your drain to the wall. Since the pre-slope already has the slope a uniform thickness, of any size, will follow that slope all the way from the drain. If you pitch it again (with another kit) it will end up with a very steep slope, knowwhatimean?
There are no dumb questions! Wait, yes there are – but yours isn’t one of them.
That’s why there are artists like you, and dumb marketing guys like me. Great stuff! I would never in a million years be able to pull that off!
Hey Darren,
Everyone has a talent. For instance, the limit of my marketing knowledge is “Buy my shit!” (Not a completely ineffective method, by the way)
See, then that means you ARE good at both!
Hi Roger. First off let me say that sites like yours are the real fruit of the internet. Your combination of candor and common sense is a God sent. We have been given at least 5 different “only right” ways to tile a new mini addition and each contradict the other. Here’s the situation. We want to porcelin tile a small hallway coming in from a garage along with an adjoining 1/2 bath and laundry room over a crawl space. The crawl space is over a garage floor slab. The bottom and 3 one foot walls of the crawl space are lined with plastic and ventilated with ducted for feed and return air into the heating a/c system, just like a little basement room (got all this design stuff from the federal government web site). The subflloor and joists have been down for about 3 months and consists of old 3/4″ non tongue and groove cdx tightly fit over 2×10 joists 16 inchs on center with spans of 10 feet. The entire area is 15ft x 6 ft. The new tile floor will meet the butt ends of a new 3/4″strip oak wood flloor sitting the same 3/4″ cdx in an open cased opening hallway so we’d like as small a transition as possible. I spoke to Shulter as i really like their products but received somewhat differing advise from their tech guy and their customer service person. Their field tech said I didnt need to cut 1/8″ gaps between the cdx edges, nor add another layer of plywood on top of the cdx because the area size and shape is so small. He said just apply the thicker ditra and tile oer the specs. But the Ditra tech customer rep (who could only read from their manuals) said I needed to make the cuts and add another layer of plywood because the cdx was not T&G and then use the smaller ditra. We like the tech’s advise because there would be no height issue with the adjoining oak floor but we want to do this right and can live better with a transition saddle than cracked tile…please advise…. my dog is highly flammable. thanks
Hey John,
Thank you – your last sentence cracked me up, I needed that today.
Your current floor has a deflection of about L850. The minimum for porcelain is 360, for stone it’s 720 – you’re above both of those. That simply means that your floor is currently acceptable for porcelain tile installation due to the joist spacing – it doesn’t bounce too much. Given that, and the fact that DitraXL adds substantial decoupling properties over a given substrate you can go ahead and use the thicker ditra and install porcelain to it. That should be just fine for porcelain. You do not need to cut gaps in the cdx.