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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Another question that I can’t find an answer to in your vast website: I am laying a boatload of slate tile. I read somewhere (maybe here?) that sealing the slate before grouting makes it easier to clean the grout off. Your thoughts? Also, I have some travertine (unfilled) in a backsplash area. IF I seal first, then fill those nooks and crannies, will that be a problem? Thanks again for all your help!
Hi Linda,
Yes, sealing slate first makes it much easier to grout and clean up. It will not be a problem sealing the travertine before grouting.
Love the website, by the way. But I couldn’t figure out exactly where to post my question. I want to lay porcelain tile over a concrete slab which was previously covered by linoleum. I’m not sure what the slab looks like underneath yet, I’ve only ripped up a few corners to check it out. Is it correct that I need to scrub any adhesives and such off the slab? And once the slab is squeaky clean, do I need any other substrate, or am I good to just use a thinset (flexibond, is it?) and lay the tile right on the slab? The house is 25 years old and in a warm climate, and until I uncover the rest I don’t know about cracking or anything.
Thanks for any help!
Hey Craig,
Yes, you need to remove any adhesive left on the slab. The pores of the concrete need to be open to allow thinset to bond to it. If you splash water on it the slab should soak it in fairly quickly, if it beads up and stays there you need to remove more.
Although an underlayment membrane is always the best idea, you can go directly to the concrete with flexbond.
One I forgot, I see you seem to Laticrete. Any comments on Versabond? I don’t want to do this job over!
Thanks!
Jeff
Hey Jeff,
Yes, the paint must be removed in order to install tile over that concrete. Once that’s done the slab needs to be able to soak in water for thinset to bond. Any of those thinsets will work fine, including versabond. A membrane of some sort is always a better option over a concrete slab, but it isn’t necessary, just better. The price of those particular thinsets will indicate which is better than the other. Higher the cost, better the thinset.
Hi Roger,
I’m planning on tiling a laundry/workroom in the basement. It has a concrete floor that was painted many years ago. Some of the paint has worn off. The floor is about 40 years old and is sound and doesn’t appear to have any cracks I can find. There is a floor drain near a wall not in the center of the room.
My plan is to remove the paint with a chemical stripper. The paint may be lead so I thought some kind of “green” stripper to remove most if not all paint wound be in order. I read somewhere the concrete should soak up some water so it will bond with the thinset. Is it necessary to remove the paint if it is sound? Should the floor be washed or etched to prepare it?
Should I adhere the tile directly to the concrete or use Ditra, Redguard or some other item between the tile and concrete floor?
As for thinset I believe I read medium set should be used for tiles of 18″ square size. At HD they have a medium set but didn’t promote it to me. Instead they promoted a thinset that supposedly handles 1/16th movement. http://www.homedepot.com/h_d1/N-5yc1v/R-100161308/h_d2/ProductDisplay?catalogId=10053&langId=-1&keyword=thinset&storeId=10051
They have some medium set but didn’t recommend it over the thinset above. http://www.homedepot.com/h_d1/N-25ecodZ5yc1v/R-100154560/h_d2/ProductDisplay?catalogId=10053&langId=-1&keyword=thinset&storeId=10051
My tile: http://www.homedepot.com/h_d1/N-5yc1v/R-203630778/h_d2/ProductDisplay?catalogId=10053&langId=-1&keyword=whitecliff+tile&storeId=10051
I haven’t been able to get a definitive answer about installing on concrete. Of course I will be preparing a dead flat floor! I learned that from the Floor Elf and also bought the tips!
OH TILING MASTER:
IS IT ADVISABLE TO INSTALL CERAMIC TILE OVER LINOLEUM ? (WOOD SUBSTRATE UNDER LINOLEUM) I ADVISED THE FREIND TO TEAR UP LINOLEUM THEN TILE……..
Hey Chuck,
No, it is not advisable. It can be done, but I won’t do it nor will I ever recommend anyone else do. You are correct, the linoleum should be removed first.
I have a question after 5 years installed 24×24 porcelain tiles (marble way) – many of them sound hallow now all over the house. What should I do with them? I am afraid they will start to crack. Please advice. Thanks, Irina.
Hi Irina,
It’s difficult to tell you what to do with them without first figuring out why they sound hollow. Is the grout line cracking or pulling away from the side of the tile? Is there any noticeable movement in the tiles?
Hi Roger,
What is the best way to make a mud bed with a pitch in a shower floor?
Hi Martin,
By going here: Creating a mud bed for shower floors and following the instructions.
Hi,
GREAT POST!
I am about to have my contractor lay 24″x24″ porcelain tiles. I want a look of one continuous floor. When I mentiones to my contractor that I want it spaced 1/16, he recommended to go 1/8 grout spacing because with 1/16 you will see every imperfection.
I am not experienced in this so I just wanted to know what the best way to accomplish the continuous look is. Im sure the best is 1/16 but is it advisable with such a big tile in a diamond pattern?
Thanks!
Hey Jack,
Unfortunately the grout line size is dictated by the tile consistency. Unless it is a natural stone it WILL have inconsistencies, no matter how small. As tile is fired in a kiln it will expand, shrink and ‘cup’. The cupping accounts for most of the inconsistencies. The larger the tile the more cupping – the more inconsistencies. A larger grout line will compensate for that. Your contractor is correct, on a floor with 24×24 inch tiles 1/8 is the absolute minimum, the standard recommended size is actually 3/16″, so he’s already doing what he can.
The best way to have a continuous look is to use a natural stone. They are actually cut to size and are normally dead-on with sizing. If you’re using a manufactured ceramic or porcelain then you need to accept that it won’t look like one large slab, there’s simply no way around that. The best you can do is get a grout which matches the tile almost perfectly.
Hi Roger,
Hopefully this is my last tile quesiton since i am almost done!! I used mosaic tile for my bathroom floor. It is flat except i found an area under the toilet that has a little dip (1/8″ ?) Should I used plastic shims which is something i read? Also someone said just put grout there before putting the toilet down and it will fill that space out. What do you think?
Hi Janice,
Plastic shims work. Do not use grout! That’s ridiculous and will eventually grind and crack out of there.
I have a question. Our master bath had carpet, but I replaced it with marble tile. I used the same marble tile that was already in the private toilet room, around the bath tub, and the shower walls. Anyway, the floor is slightly (about 1/16″) higher than the old marble tile in the toilet room. I really don’t want to rip out the marble in the toilet room. Can the few new marble tiles that will butt up with tiles in the toilet room be planed or sanded so they will be flush/even/flat? If so, should I have someone do it before I thin-set them, or can it be done after I thin-set, but before grout? Thanks
Hey Troy,
It can be, but you’ll normally NEVER be able to match the finish on the face of the tile. It would be better to place some sort of transition strip in that doorway between the new and old, maybe a small diagonal row of the same tile which can be sloped just a tiny bit to meet each height. If you do want to go the initial route it’s best to do it after they are installed.
Hi, what is the best sized tile spacer to use on a hot tub surround like the one pictured in your “flat tile” posting? Would a 3/16″ be to wide? Thanks.
Hi Carol,
Grout line size is mainly a personal choice. 3/16″ would be huge if you are going for a look similar to the hot tub photos. I normally use 1/16″ grout lines, that’s what those are.
Hi Marc-
I have a cement floor and I am new to laying tile. I am tiling an 8 foor by 3 1/2 foot area, which will be bordered by river rock, which will then be flush against existing wood floor.
I am planning on the laying the river rock border first, to make it flush with the floor, and then laying the tile flush with the river rock? is this a winning idea? Any major things to look out for?
Thank You.
Hey Marc,
If you’re attempting to lay tile flush with the floor then you have the order correct. It’s always easiest to begin at the wood and work away from it.
Great info Roger, thanks. I am a designer and just went over to see the tiling that a contractor had finished for me in a small bathroom.
Much to my dismay, there were several tiles on the wall and one on the floor that were not flush with the neighbouring tiles. When I called the contractor to ask about it he said that it was because the tiles were large (12×24″) and the grout line I requested was small (1/8″).
I think he feels I am being too particular to want a “flat” floor.
My question to you is … am I ? and if not …what can be done now.(the tile was grouted today).
Thanks for any feedback you may have.
C.
Hi Colleen,
It depends.
Is the tile in a running bond (brick) pattern? If not then no, you aren’t being unreasonable, it should be flat. If it is then it should be offset by 1/3, not 1/2 and the grout lines should be a minimum 3/16″ (normally – see below) to compensate for cupping.
How much cupping is in the tile? That is the amount that the center of the tile is ‘domed’ compared to the outside edges. This means that the ends of the tile are lower than the center or center of the edges. Place two tiles face-to-face and squeeze one end tightly together – the other end will show you how much cupping you have. Attempting to place the end (corner) of one tile next to the center of the edge of the one next to it will make it absolutely impossible to keep the installation flat – it needs to be offset by 1/3 rather than 1/2 to compensate. Even then you’ll never get it perfect. This variance will also dictate the minimum size of grout lines you can have for that particular tile. The closer together they are the more that difference will be noticed.
There are several factors that go into deciding a particular pattern and grout line spacing. The matter of being too ‘particular’ depends on both parties understanding the limitations of any given tile with a given pattern.
So whether or not he KNOWINGLY installed it incorrectly lies in whether or not he understood those limitations. He should know them, it’s part of his job. It is, however, something that a lot of contractors either simply do not know or choose to ignore.
Whether or not you are being too particular lies in whether or not you understood it. Do you? Or did you when you set specifications for the job? Most importantly – do you now?
It sounds like I’m just being an ass, I’m not trying to be. There is a lot more involved with tile installation than most people think. Persons dealing with the installation end as well as the specification end need to understand the limitation of all the products being installed and the various compensations available for those limitations.
To be honest it sounds like a case of neither party being fully aware of the limitations of large format tile. I’m trying to educate people – I’m only one elf here people!
I would suggest a copy of the TCNA handbook for tile installation, if you don’t already own one. It explains all of these things.
I have a question???? Do you have to put the thinset directly onto the floor, wall, etc… or can you put the thinset onto the back of the tile 1st then set tile onto the floor,wall. I do a lot of small areas. small bathrooms, shower walls with shelve inserts. Because of the small areas it require a lot of cuts (which take time). I found out that sometimes my thinset will start to dry out and the tile will not stick as well if i put to much on. If i wait and put the thinset on the walls 1 or 2 sqft at a time its messy. the thinset will fall off trowel onto already place tile or the area that my last piece or two will be to small to get my trowel into. If i wait till the tile is cut and checked for correctness and then put thinset onto tile and put into place it works out easier for me. Plus i can jump from wall to wall and keep my cut man busy. What do you think about this process? I have had to pull some of the tile back up to get correct height, and the tile and thinset has stuck very well. I do not see any difference between the processes. Thanks
Hey Chris,
You need to put it on the wall or floor. The difference is the bond that you’ll get to the substrate. By placing it on the back of the tile you don’t get full contact to the substrate – you’re simply setting the thinset onto it rather than burning it in with complete coverage. It will work, it’s just not a good idea and will not be as durable long-term.
Hi Roger,
I hope your days are going well.
A friend of mine had his bathroom walls and shower tiled. They are a brown and copper color without much of a shine. He really likes the way they look when they are wet, More shinny of course. He was wondering if there is anything he can put on them to give them that wet shine look.
Thanks,
Steve
Hey Steve,
Any good enhancing sealer will work. I like Aquamix’s Seal ‘n’ Enhance. It’ll give the tile a wet look.
Hey Roger,
You were helpful with my question about soft joints on Facebook. Thanks again.
Now here is the really scary question. First, the good news (I think) is that all the brands you love are the brands my guys used.
Now for the scary part. All the tiling was done on the cement slab under the old mexican terracotta which did not leave a, shall we say, smooth surface. The rest of the tiling was done on cement slabs that appeared self-installed with no expansion joints, and cracking in a few places. This is Florida, and the house get’s sunset and sunrise expansion and contraction daily.
Anyway, the master and guest bedrooms were pretty flat and not cracked, as they were part of the original house, and they had a laminate flooring on them.
The main room (kitchen, dining, sitting, all that stuff) which is around 1200 square feet is the terra cotta graveyard.
The sun room (every dam* room in houses needs a name these days!) was a cement slab extension to the house. It has rounded up in the center, and cracked. It was literally the a spherically convex surface starting in the cracked center and working it’s way down toward the walls (6 walls, did I mention 6 walls).
Anyway, the big contractors who just sounded full of it, wanted to grind it all down and would not quote me a price for the “pre” work. Just said “at least a few thousand.” F* that. Give me a price or range or somethings.
Anyway, I was referred to a friend who was going directly to the tiler behind one of the big contractors for the million dollar water front homes.
Not only was his price the best (no surprise there), but all I wanted was diagonal throughout the whole house. One line. Instead, he suggested small 4×4 stone tiles to visually separate the kitchen, a different pattern (offset squares) inside the kitche, and a faux-french tiling made by cutting our 20×20 tiles into 2 sizes (small and large) square for the sunroom (aka the convex dome).
Further, he said he could create a flat surface by sealing the cracks with some magic yellow stuff and just by taking his time with the thin set. Oh, did I mention the 10×20 border tiles he cut in the master bedroom as an outline to the room.
All for an unbelievable price. I had to go for it. The recommendation came from a high source, and I blew my wod in a cash bidding war for this bank owned ranch.
Anyway, on one hand, the tile looks beautiful and the designs are something we would have had to pay a whole lot more for.
On the other hand, there is tons of lippage, and the grout depth was not consistent, a bigger problem in our home which has constant shadows from sunrise in front to sunset in the back.
After complaining a lot, he had his guys re-grout, but only after finding your blog did I learn you needed to remove all or enough of the old grout before adding more. No surprise, a couple weeks later the grout was cracking. So I called him out on it, and his top guy say on his butt with a blade and removed all the bad grout totally replaced it.
I was hoping this would fix some of the shadowing from the uneven grout. It’s actually made it worse, as the new grout is to the surface, and the old grout in inset a bit.
Oh, and one more thing… they sealed the first round of grout like 2 or 3 days later. I’m now waiting the 28 days I keep reading about before we seal again.
Now, what the heck can I do with these 28 days to mitigate the imperfections.
I know some times will just need to come out and be reset. But there are so many that I can do them all. Is there any trick to help distract the eye?
It’s 20×20 porcelain tile with 1/8th spacing…. except in the slope room where they seemed to “improvise” to help reduce the curvature. Believe it or not, with no sanding or prep, other that the yellow goop on the cracks, the slope is significantly minimized.
The main guy is a talented tiler, but to make a buck on his side jobs (like mine) he occasionally brings in the B or even C team. And it’s obvious who worked where.
Is there even a question in this?
Is it better in the 20×20 1/8th to have some depth to the grout, or is higher better. I’m wondering if created more shadows by filing down the high grout will all least create consistent shadows.
This is my first home, and my life savings — I should be glad I got the million dollar design for pennies, but you get what you pay for, and every time I look down at lippage, or grout lines of varying height, I want to, well, you know.
These guys are still working for me, believe it or not, on all exterior stuff now, so when the grout is fully set, I can and will get them to make some fixes, I just have no idea what fixes to ask for short of removing and resetting (which they have done 3 times for me already on tiles that I had issue with).
Like you said in another post, you have to solve the underlying problem, or the symptoms will re-occur but in the case of lippage and shadows, I have no idea.
Please tell me you have some tips, tricks, suggestion or a hammer for the topside of my head!
Thanks – you rock.
Hi again Roger,
Here are a few (read, a few too many) photos to show you what I am describing.
Granted, I focused on the problem spots, and not the good areas (mainly out of fear you would find fault there too!)
Also, I forgot to mention the pre-existing tile by the tub which had baseboard leading up to it, so there are photos there. Lot’s of water damage behind the baseboard, so not sure how to handle that, but I’m sure there is a post on this site somewhere!
https://picasaweb.google.com/109987112954743108286/TilingIssues?authuser=0&authkey=Gv1sRgCPKqiLfk2P3cVA&feat=directlink
Thanks again!
Hey Mark,
You do have a LOT of lippage on that floor. My first question was going to be about the amount of cupping in the tile but you do have a couple areas that look like they were laid well with the same tile – so I don’t think that’s the reason. It looks to me as simply a poor installation. In the ‘cupped’ room there will be a LITTLE bit of inconsistency in the grout spacing, but that is excessive. Once the tile is set there isn’t anything you can really do to fix it short of removing and replacing the tile. And you can’t just do it with one of the tiles – once you lower one edge of the tile the other side is going to kick up a bit creating the same problem – one tile over. It is one of the few things that can not be fixed once the tile is set.
The grout issue – I see a lot of area where there is light and dark grout. Some of them are due to adding more grout at a later time, as you’ve described, and some it looks like is due to efflorescence. It will not even out. On larger jobs a lot of crews tend to add too much water to the grout to make it easier to install and use too much water to clean it up. In an attempt to rush through and get done they attempt to make it easier and end up with inconsistent color and low grout lines. The grout should be nearly level with the face of the tile. The low grout lines are likely due to the grout shrinking more than normal – due to using too much water. As it evaporates the grout will shrink. Short of replacing all the grout there isn’t much you can do there either.
Unfortunately all the information I have for you is bad news. It is a matter of poor craftsmanship which requires removal and replacement of the problem areas. Sorry. The crack on the side of the vanity should be siliconed rather than grouted – same against the tub. That’s why it’s cracking. So that’s an easy fix, I guess…
Well, I suppose that is what I expected to hear. Perhaps I’ll get them to replace a few really bad tiles, and then learn to grout myself.
Will properly re-grouting to level help at all with the appearance of minor lippage?
Also, are they grout dyes or other cheats to darken the light spots where they are actually level?
Thanks again!
You can use an enhancing sealer on it – that will darken it somewhat most of the time. Regrouting may help the LOOK of the lippage, depending on how well the grouting is done.
Thanks again Roger!
This actually gives me much hope. I’m going to take the time to learn and regrout the major offenders myself.
To improve the look when regrouting is it any way that is better than another, for example, the angle of the grout being straight from edit to edge – or does it just vary by lippage?
The sealer we bougth is Aqua Mix Rapid Cure Sealer’s Choice Gold (Low VOC).
Is this any good?
Will this do the trick or do you recommend something else? In this case, cost it an issue – this is a major investment I’m trying to protect and enhance! My first house!
Thanks again of gracious master of all things flooring!
Oh, and do I really need to wait 28 days before sealing?
Mark
The look will vary according to height difference, angle, whether it’s a corner or not, etc. No one method will work for every tile. Sealer’s choice gold is a good sealer, although I’m not a fan of rapid set anything, probably just slow in my old age.
No, you do not need to wait 28 days before sealing – you can seal it right now if you want to.
Any suggestion for a good brand enhancing sealer to help with the darkening?
Can we use that on top of the stuff we have, or will that reduce the darkening effect.
So much to learn. Definitely buying your ebook right now.
Thanks for you help.
Hi Mark,
I like aquamix seal ‘n’ enhance or dupont’s enhancing sealer. I don’t know if you can use that on top of the stuff you have now – I have no idea what you have now.
Dear Mr Elf, Thanks for all the tips ! What is your opinion of the spacers with levelling wedges ? I saw them at Lowes the other day ( even though I can’t find them on the website )
They kindof look like these : http://www.kwiksplit.co.uk/acatalog/copy_of_copy_of_Raimondi_Tile_Spacers_and_Levelling_System.html
Hi AC,
There are several leveling systems out there. The two I’ve used are LASH from Qep (that’s the one you’re talking about) – it wears your fingers out quickly and you need a LOT of tile adhesive beneath the tile for full contact. The little foot on the bottom of the strap is fairly thick (relatively) and requires a lot of thinset to ensure a full bond. I do not like that one. For just a small shower or bath it does work fairly well, though. You need to pay attention to space beneath the tile, though.
I have also used, and still use, the TLS. It’s similar but much, much better. Also – expensive.
Thanks as always ! I am thinking of using 12X24 porcelain tiles for the bathroom and will give the LASH system a try. And you are right – the TLS is a bit rich for me
– AC
Roger,
Your site makes me want to take on more tiling projects around the house. I’ve been lurking on it for months now, I’m sure my wife thinks I’m on a very different kind of website. I’ll just let her wonder. I couldn’t find an answer to my question though. For our small bathroom floor we picked natural slate tiles. Since the top is an uneven surface, what is the best way to keep them level to each other as I move about the room? Thanks for the wealth of information you’ve put out for a simpleton like myself.
Trevor
Hey Trevor,
I saw you lurking over there in the corner.
I normally use medium-bed mortar and a large trowel (1/2″ x 1/2″). That allows you to adjust the tile up and down as much as you need to get the face of the slate as flat as possible. Other than that I simply use the same technique I’ve described above. The secret is to get a lot of mortar beneath the slate so you have room for adjustment.
Wow, such a clear great answer, it makes me think maybe I can sneak another question in here. If I’m using epoxy grout on this slate floor (and in the shower that includes slate accents) do I need to put a sealer on the slate tiles before applying the grout? I’ve read a few comments and it seems like natural stone might absorb some of the water from the grout but I wanted to make sure that was correct for slate too.
Thanks
Slate is worse than most natural stones as far as absorption rate goes. You want to seal the face of them a couple of times to get a really good seal on the face. If you don’t it’s nearly impossible to get all the grout off of them. If you’re using epoxy it IS impossible. The sealer gives you a good layer of defense so the face of the stone doesn’t absorb all the stuff that will get on it as you are grouting.
Have a 200 sq. ft. room that I will put travertine down on. It has a 1/4″ cement board subfloor over a 3/4″ plywood floor.
Want to install A NuHeat radiant floor mat under the travertine. Any experience with this? Directions state to thinset mat to floor first, then set tile over mat when dry. Any tips?
Thanks- Dave
Hi Dave,
As long as you have thinset installed beneath your cement board that order should be fine. If not – you need to do that. The temperature variation in a heated floor leads to excess movement, the substrate needs to be properly supported to compensate for that. It is actually much easier to install the floor mat with self-leveling cement rather than thinset, but thinset works fine. Make sure you get a relatively flat layer over the mats or the installation is gonna be a pain.
Do you suggest I thinset the mat to the floor and then use “self-leveling cement” over the top? (a very thin layer?)
I was also told that I can use “liquid nails” to adhere the cement board to the plywood- and then screws along the perimeter of the cement boards as well? Is this true?
Yes, but most slc’s have a minimum thickness they can be poured – make sure you follow that.
No, you cannot use liquid nails for your backer beneath tile. It needs to have thinset beneath it and it needs to be attached properly – every 6-8 inches – with the proper fastener. Liquid nails will leave voids beneath every spot there is not liquid nails – that leads to movement.
I am re-doing my bathroom, and the floor is currently like a skate park. The floor is 3′ wide by the tub and has a good 1/2″ drop on one side. Here is the tricky part. I think it was built that way. Looking at it from below, nothing seems to have moved, the joist is just bowed. Looking at the floor (1″ square tiles), there is not a single cracked tile or grout line. It was installed in the 70’s (it’s an AWSOME lite blue color). The marble door threshold is cracked, but interestingly enough, that is in a place where the floor is flat.
I was originialy going to jack up the bowed joist, sister it, and then proceed, but I think that may cause more trouble in the long run. My plan is now to just leave the subfloor bowed as it is. Level it with thinset, thow some some Ditra, and then go from there.
Comments?
Thanks
-dave
With that much of a drop I would be leery of using thinset to level it out. Most thinsets can only be built up to about 1/4″ or so without excessive shrinking. I would be more apt to leave it as is (it probably was built that way…) and use a Self-leveling Cement to level out the floor. Go right over that with the kerdi and you’ll be nice and flat.
I have just a few end fragments of tile to add to a bathroom. They will be located under a bench along a wall and not noticeable much. Can I set these small pieces with sackrete or grout? I am retired on a tight budget and
do not want to buy a whole batch of thinset just for this small job.
Hi Jeanne,
You can set them with sakrete if you need to – it’ll work fine.
I’m hoping to install 1700 s.f. of 18×18 porcelain tile soon. What thinset do you recommend, if money is not an issue. Our neighbor remodeled and now has popping tile. We live along the Tx coast and our soil is black gumbo which swells and contracts. I want to do this right, as this is a second home that our children may want someday.
Thanks, your friend in Texas.
Burke
Hi Burke,
If you’re going directly to the concrete I would use Laticrete 254 Platinum or Laticrete 125 sound and crack adhesive (thinset). The 125 would be your best choice as it will compensate for a LOT of movement in your concrete without transferring through to your tile.
How far out of “level” can you make up with thinset? The contractor “relevelled” the floor with new joists and subfloor but I ran a string end to end over the length of the floor and it dips down 1/2″ over about 8′ and then bat up again…also he wants to use a ceramic tile adhesive and not thinset…any issue with that?
Thanks man, you rule!
Ceramic tile adhesive? Like mastic? Absolutely not. Not only is it not approved for tiles over 8″ x 8″ square (or smaller with some brands) it cannot be built up to any thickness at all above and beyond the normal 1/16 – 3/16 beneath the tile.
Standards for flatness on a floor are no more than 1/8″ in ten feet. What you have there is actually a 1″ variance over eight feet. Way too much. Medium-bed mortar can be built up quite a bit, the amount is dependent on the brand. It will state maximum thickness on the bag.
Roger – Is it necessary to complely set the tile all at once as opposed to doing some on one day and the remainder the next day or two?
Thanks
Hi Don,
Good god I hope not. Otherwise I’ve been doing those 2000 square foot jobs all wrong!
You can stop wherever you want and begin again whenever you want. Just make sure you clean the thinset out of the corner along the edge of the tile before you stop, if that little ramp of thinset cures there you’ll need to scrape it out to get the next tile to set correctly, just do it before it cures and don’t leave it there overnight. Also it’s easier to use some painter’s tape to tape the last row you laid to the row before it. This ensures that the tiles in the last row will be where you left them the next day and not slide anywhere.
Oh wise elf. I have a small bathroom straight from the 50’s (and not in a good way – think pink tub). I’m replacing the tub as well as the floor tile (small 1″x1″ and 2″x2″ squares mixed with 1″x2″ rectangles in a random pattern, not sure if it’s porcelain or ceramic). When I pulled the tub out, it appears the tile floor was laid in a bed of 1″ thick concrete or cement. Will my dog burst into flames if I attempt to put thinset and new tile on top of this already solid surface? I’m slightly concerned that the thinset might not adhere to the existing tile properly.
To make matters more complicated, the tub we removed was 4′ x 6′ (they don’t make ’em like they used to…and maybe that’s a good thing) and we’re replacing it with a 3′ x 6′ tub. So the new tub fits nicely in its 6′ alcove, but there’s a foot of exposed subfloor between the apron of the tub and the 1″ thick existing tile bed. So if I don’t rip up the existing tile bed, can I just add plywood/shims and backerboard to flush these surfaces?
Hey Charlie,
You can go over the existing tile. If it has a shiny surface you’ll need to rough it up or scarify the surface. You’ll also need to use a thinset specifically made for tile over tile installations (it’ll say so on the bag).
Mix up some deck mud and fill that one-foot expansion space with that. It’ll be nice and solid and won’t cause problems.
That’s good news, thank you. Any recommendation on what I can use to rough-up the surface of the existing tile? Do you do that chemically? Or will 80-grit sandpaper suffice or do I need to whip out a power tool? Additionally, should I raise the tub up by adding plywood under it (so I don’t bury the front tub apron by an inch of deck mud or does that even matter?
Is deck mud any different than cement? Do I need to wait for that to cure then add thinset and tile, or is it safe to just push the tile into the wet deck mud? Thanks in advance.
You can use chemicals, but they really suck to work with. You can use sandpaper, but it takes forever. I have a cup wheel for my grinder that I use, it’s quick and as long as you hook up your shop-vac it’s fairly clean.
I would raise the tub, but you can bury it if you want, doesn’t really make a difference. Deck mud is sand and cement, it’s not the same as straight concrete. Yes, you can set the tile before the deck mud cures.