Before installing tile on your floor you must make sure your floor is properly prepared.  A properly prepared floor does not have to be level. It must, however, be flat.

The only time the levelness (is that a word?) must be taken into consideration is when drainage is an issue, such as on a porch or in a shower. In those cases you must make sure your floor is not level – it has to be angled toward a drainage area.

If your floor will not be subjected to water regularly, such as a kitchen or bathroom floor, it does not necessarily have to be level. That does not mean you can have a 45 degree angle from your door to the cabinet (although I suppose you could if you wanted), it just means if your floor is not absolutely level it will not negatively affect your tile installation.

One of the things you must make sure of, among other things, is that your floor is flat. If it is not it will be difficult to set your tiles without what we call “lippage”. That’s a ridiculous word, isn’t it? Lippage simply describes the difference in the height of two adjacent tiles. If you have a tile that sticks up higher than the tile next to it you have lippage. You don’t want that. Starting with a flat floor helps prevent it.

When prepping your floor for tile trade your level for a straight edge. Don’t be concerned with how level your floor is, be concerned with how flat it is.

{ 446 comments… add one }

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  • Jeanne

    Roger, Great amount of info, you are now on my homepage! I am installing a 17 inch wave edged tile in a 9×16 entryway living room addition. I have t&g osb flooring and have floated a 1/4 in fiber board. I am going to put a wood stove in this area and the installer says I need 1/2 inch fiber board for hearth. I thought since it is a fairly small area I would just put another 1/4 inch over all. My question is do I tape and mud the first course of fiber board and then thin set the next layer and tape and mud it also or can I just screw the second course to the first without floating and then tape and mud the second. Then thinset and tile? Thanks

    • Roger

      Hi Jeanne,

      You need to put thinset beneath the second layer, then screw it and tape and mud it. You do not need to tape and mud the first layer when going over it. You also do not need 1/2″. Backerboard (especially fiberboard) add absolutely zero structural stability. You can if you want, but it won’t help a damn thing. :D

  • Marty

    Hi Roger,

    I am getting ready to install wood-look 6″x 24″ rectified tiles with 1/8″ grout line in my kitchen, living room, study and hallway over a concrete slab. The slab in in good shape. No cracks, but there are a few ‘bumps” where if you lay a tile over it, the tile toggles an 1/16 inch, other than that the floor is flat. Will this be a problem? If so, what should I do?

    Also, the Big Box store tried to sell me RED GARD to protect against slab leaks and cracks (I live in earthquake territory). I bought it, then returned it because, I think RED GARD is for ‘wet’ installations (showers, etc.) and if there were a slab leak, I would want to know about it.
    As far as membranes go, do you think they are necessary over a concrete slab? I am thinking, if I use Flexbond, that will be good. If there is a quake big enough to screw with the tile, no amount of membrane will help. Your thoughts?

    Grout – I hear epoxy grout is harder to use? your thoughts?

    If I use sanded grout, can I add a sealer to the grout itself before applying to make it more resistant to dirt?

    One last question. I removed vinyl 12 inch tiles and scraped the old adhesive off with a 4″ razerblade scraper. It came out real smooth, but I was told the floor is almost TOO smooth. Is that possible to get a floor too smooth so adhesive won’t stick??? I also washed it with TSP.
    Thanks

    • Roger

      Hi Marty,

      First off, to check to see if your slab will allow bonding just splash some water on it. If it soaks into it within about 15 seconds or so you’re fine. Bumps that small are easily compensated for with thinset as you install your tile.

      Redgard is used for wet areas, however, it was initially manufactured as a crack-suppression membrane. It works very well over concrete. you are correct that no membrane will save it from a quake, but I always install a membrane over concrete. It’s just cheap insurance for non-quake events, like the slab cracking (which it WILL do).

      Epoxy is harder to use, but well worth it. You can not add sealer to your grout, but you can use a product like grout boost if you want that. I DO NOT like it, but that may just be because it screws with the way my grout ‘feels’ and works. I don’t like that. When done properly it does what it is supposed to do.

  • Amanda

    Hi Roger,

    I have a question regarding an uneven shower wall. I noticed the wall was not flat while putting up the cement boards. My SO assured me it was small enough of a difference that we could fix it with thinset. I have finally convinced him that we need the wall to be as flat as super-humanly possible, especially considering we are installing very large tile (12″x24″). The only problem is the last thing we’ve done was to tape and mud the seams. I’m now banging my head against that same wall, as it would have been so easy to take the cement board out and shim behind it had we not already taped & mud. Can we float the wall with mud or thinset to get it flat, or do we need to rip out the cement board and start over? The dips in the board vary, but the deepest appear to be about 1/8″.

    Thanks,
    Amanda

    • Roger

      Hi Amanda,

      While you’re correct about the wall being flat to begin with, at this point it would be easier to flatten the installation with thinset behind the tile as you install. A 1/8″ dip isn’t a whole lot to make up behind your tile, you should have about that amount of thinset behind your tile when it’s installed anyway. Just make sure that when you go over those areas you pull the tile back off to ensure you have full coverage, and if not, put some more thinset on the tile in that area.

  • Kristin

    Roger,
    Stumbled onto your website today and glad I did before making my daily trip to the big box store. We are in the middle of a bath renovation and are having issues with the floor. After removing the original 1952 tiles that were set on 3″ mud bed we found more cement instead of the angled plank subfloor that’s in the rest of house. We’re talking thick cement poured between the 16″ o.c. joists. Not to mention there are dips and raises like mad. So my original plan of backerboard under my 6×24 tile was shot. We have put down plywood on top of the cement, glued and nailed to joists. But it is not flat or level. My plan was to use ditra but need to make surface flat. Do you recommend using thinset, planipatch or slc to flatten? Or maybe even another layer of plywood? It’s a very small bath, roughly 45 s.f. of flooring.

    • Roger

      Hi Kristin.

      SLC would be your best option. You can do it with ditra and a straight-edge if you’re not out more than about 1/4″ over the whole thing, but you really don’t want to build thinset beneath your ditra much more than that. It will shrink over time if you install a whole lot under there. SLC would be the easiest, and best, option.

  • Laurie

    Roger,
    I seem to be running into every problem you can here. I have a really warped floor joist, and the osb seem on it was raised up. So I planed it down and thought it was fine, but now that the hardie is down I can see it is not flat. I have large 18 inch travertine that has sharp edges without bevel, and don’t think I can lay it without lippage. Is self leveling concrete the best product to use before I tile, or something else? Thanks again!

    • Roger

      Hi Laurie,

      Yes, slc would be the ideal solution for you.

  • stan

    hi there and thanks for your informative website. I have a tiling/ sub floor conundrum. The floor is green chipboard and I will be covering it with 20mm marmox backer board.

    Unfortunately there is a high spot in one corner of the room caused a by a sloping floor joist that is also acting as a structural support for the wall above – basically I can’t get to it. I’ve used a ton of thin set under the backer board and it has set firmly and reduced the dip somewhat.

    Now how should go about tiling this kicked up area that is approx 1 inch higher then rest of the floor?

    I have never tiled before and this is my first project :)

    Help!!! :eek:

    • Roger

      Hi Stan,

      If it is 1 inch higher then you need to do something more than fixing it with more thinset.Can you sand the area down? Or cut out the backer over that area and float it out? You can not make up that much difference with thinset.

  • John

    Roger:

    You are the man. Thanks for sharing your expertise in a digestible and enjoyable format. I tip my “pepsi” to you.

    I’ve got a question about sanding down the top mortar bed to reduce it’s height near the drain and to make it flat (not level). A few weeks ago I poured, packed down, and screeded the mortar bed following your instructions. I used premixed S-type mortar from HD (I think Sakrete). Unlike your pic of a sandy-ish finish, it is fairly smooth, more like floated concrete. (Maybe that means i used too much water?) Anyway, the bed isn’t as flat as I had hoped, and moreover the tiles look like they will be almost 1/4″ higher than the drain instead of flush (i.e. I made the bed too high near the drain and the Grecian marble floor tiles I got from HD are extra thick at 3/8″). The look of the bed (smooth instead of sandy) makes me concerned that sanding won’t work well on it.

    I plan to try sanding down the mortar bed this weekend to flatten it and reduce the height near the drain. I was hoping you could clear up some details before I give it a shot: Should I just use 80-grit with my hand-help oscillating sander, or do I need something heavy duty (like a belt sander)? If sanding doesn’t seem to work what are my options? I’ve read your suggestion of using thinset to flatten if need be, but I don’t want to add more height near the drain if I can avoid it. Do I have to chisel it out and start again.. or do you think a 1/4″ drop from tile to drain acceptable?

    Thanks,
    John

    • Roger

      Hi John,

      Did you use straight concrete? Because if you did that’s why it’s smooth and not sandy. And if that’s the case, and you are using a traditional method on the floor with the pvc or cpe membrane beneath your top mud deck, it should be removed and replaced with deck mud. Water can not flow through straight concrete like it does in deck mud, and it needs to be able to flow to the weep holes.

      You can still use 80 grit sandpaper, it’s lower it just fine. No, 1/4″ drop to the drain is not acceptable to me, the tile around the drain should be flush with the top of the drain grate.

  • David Tyner

    :bonk: I just bought a new house. The master bathroom had a couple of cracked tiles. ( ceramic floor tiles) Builder replaced said tiles. Different tiles cracked a few weeks later. Builder had his guys rip the tiles up and replace them. Well, lots of lippage and uneven tiles. Toilet was rocking, shoe molding wasn’t flat against the tile. Tile guy returns to repair issues. (I work third shift) when I woke that afternoon he had grouted around my toilet, ran a heavy bead of caulking on the tile/molding junction. Caulking looked like terrible, the tile beside the toilet is so unlevel its off the charts on a bubble level. Builder said he can’t make us happy. Is willing to pay another contractor to do repair but will deal with them. Is these practices acceptable and should I let him wash his hands of the matter? Very frustrated. Thanks David Tyner

    • Roger

      Hi David,

      It IS NOT acceptable practice. The problem is that most builder’s ALWAYS take the lowest bid, and get an installation representative of that. I would NOT let him wash his hands of it, I would insist that he find a qualified contractor, it is his responsibility to do that, no yours. If you find someone you also let him off the hook for any future problems. It’s his problem to deal with – make him deal with it. It’s not your issue – it’s his.

  • Francois paradis

    I’m glad to see you addressing that level vs true (flat) issue. I get a good laugh every time I see people using 27bags of self leveler when a couple of bags of planipatch would have done a better job….especially since they were probably laying on wood substrate, didn’t prime for the self leveler and seem completely unaware that we’ll be able to lift the whole thing up in sheets with a pinky finger when all is said and done. :bonk:

    • Roger

      I love removing jobs set like that. :D

  • Dusan Ilic

    Hi Roger,

    If I would have only known about your website few months ago…when I decided to prepare the underfloor for my 8 sqm kitchen in a 100 yrs old house… where in the beginning I only had six ~4″ wide 7feet long wooden beams not in good condition at all. To make the things more complicated, there was a classic parquet already laid in a room, better call it a space as there is no wall between the kitchen and that parqueted space, next to the kitchen.

    So I had a straight line of the parquet in length of 9feet where adjacent to it I wanted my 18″x18″ 10mm thick floor tiles to be laid at the same level.

    I could not trust any of the tilers I had contacts with that they would do the work properly, for 2 reasons: condition of the underfloor (there were wooden planks on top of the wooden beams, but all uneven, loose, (dis)connected with rusty nails to that main beam supporting structure, who knows how many times times moved in and out during the life of the house (and this renovatiojn project) etc, so they had to go out, as well as 250 3″nails which kept them in place since 1907. (This is all happening in The Netherlands).

    What they were proposing was to just leave the wooden planks where they were, and put screws in between the nails to fix them firmly, put 9mm multiplex boards on top of that and then fix the tiles. Nobody wanted to guarantee the same height of the tiles and parquet, in fact they all said the tiles will have to be few mm higher than the parquet. Nobody wanted to deal with the details like contact / transition from parket to tiles as that was supposed to be resolved during the work, when it becomes clear how it all will be looking, height-wise. Shops over here do not offer solutions that I could relay on for that type of transition, whatever I saw was ugly and as I did not want any height difference I started to use my brain (wrong!) and decided to remove the planks, repair the beams (take all the nails out as they were really, really rusty – the space was used both as a kitchen and a bathroom for almost hundred years; and one can imagine how that bathroom was looking (those houses originally did not have bathrooms and toilets, and in this case there was a wooden kind of shower bathtube-box which was removable when not in use, with a shower above: so beams were exposed to water, damage was/is probably beyond reparation, and the reason why all this had not been changed (and to understand the catastrophy, this renovation project is dragging 3 years) was that few experts advised that both the beams and those planks were just perfect everywhere and that they should not be touched. I liked that and thought that I really had an excellent deal with this house… Later on, it proved to be far from that.

    When the parket floor was planned and made, I was assured that there will be no problem to finish that kitchen area with installation of the light concrete substrate (they use something called Lewis plates for both shaping an reinforcing the concrete floors for bathrooms and kitchens), but that in my view could and should only be put when the supporting beams are really in good condition, and mine proved not to be, plus the amount of previous interventions on putting water, heating, electricity pipess through those weak beams is really worrying…)

    When it came to the moment to consider finalisation of the kitchen, it became suddenly clear that there is not enough space for the concrete, as it will make the surface higher few cms, plus it was only then the moment for me to see what was the condition of those beams and get it that in this part, unlike on other parts of the house, the situation was really bad. Yet the builders suggested posting the concrete – it is the fastest method, they just spread those plates on top of the beams and mix and pour that beton…

    This has become way too long. I can send you some photos as what I did probably nobody ever did during such renovations.

    As parquet floor was already there, there was no intervention possible on repalcing the beams and I had to live with what I have (and there are traces, many traces, of worm activity in the past…

    I decided to try to repair it from above at least (there were parts of totally rotten top surface on those beams) and I removed all the nails (10 days of work, crazy) put wooden plugs with use of epoxy, and repaired the surface with additional wooden segments and epoxy, so that I am sure to have a solid material to support the multiplex boards that I decidded to use as underfloor for tiling.

    The problems were also in existing position and stiffness of the beams – some were slightly rotated, everything was wobbly…

    So I decided to connect the beams laterally with the use of similar size of solid wood material i.e. 3″x6″ beams which were cut so that they can fit between the old beams, and I somehow glued them with the use of 1 component polyester-based professional glue for wood. I had to help myself with adding tiny chips of wood to hold my reinforcement beams in space and at the end the result was beyond expectations in terms of bearing capacity – it simply became something that is looking as one indestructible non-movable grid, (how will that affect the general shrinking and expanding of wood I dont know…, somebody who I can trust advised me that the method is fine, although very complicated and expensive, and that there should be no strucutral problems afterwards).

    On top of that grid I put six 3 cm thick waterproof multiplex boards – yet another expensive material, and I connected it with the beams i.e. grid that I constructed, with the use of screws and 2 component polyester based wood glue which is the best one on this market. Compared to the one component glue that I used for the grid, which is almost the same in price as the 2 component one, this later one is has less expanding properties and is more elastic.

    I was advised to leave the half cm gaps between my multiplex boards, but as the method of work involved the use of glue in excess of “normal” usage, as the glue was there also to fill in the imperfections and gaps between my multiplex boards and the grid, the glue wnet into the space between the boards and at the end I filled all those spaces (like grouts) with it.

    I have used te professional parket sanding machine to make the conatcts between my mulitplex boards even, as in spite of all care and preparation, there were slight denivelations at some points on my final fixing action.

    So, to finally come to the point: I have a very solid wooden surface that looks flat and also horizontal, but it is not flat. When I put my big tile on it, I see it is not laying 100 % flat on the wood. How can that be overcome? I cannot work on the wooden underfloor any more, and I think nobody can make it 100% flat without using some additional self-levelling material (which does not exist here on the normal market), and then I will again get into the situation that my tiles go higher than the parket.

    Regarding the contact with the parket, I managed to put a very nice thin messing stripe that is connected with the parket subfloor via nails and also glued with epoxy, so it became integral part of the parket side, and I want the tiles just to be next to it. Making that stripe was a task of its own as it is not a designated thing for such a purpose. From what I saw as a possibility to be used during the installation of the tiles, I concluded that nobody could ever make it look nice (they use L-shaped metal profiles similar or same to what are used on making corner connections on walls in bathrooms, etc) BUt they are either plastic or RVS or aluminium and I did not like that, plus there will be a problem with height and “grout” between something like that and my parket. Now I have the stripe 100% close to the parket, and at the same level.

    Out of those 8 sqm only few sqm will really be visible and walked upon, how to choose the best laying method so that at least if I decide to leave this final work to somebody else, I do not get what in Holland ususally is the case, very poor quality or systematic mistake as everybody cuts corners wherever and whenever possible…. Is it possible to overcome the problems of the surface not being completely flat (imagine 6 multiplex boards placed so that their longer sides reside on my beams, so I have one long “grout” between them, and in theory different angles, plus in spite of the 3 cm thickness, screwing the boards caused a bit of deflection at screwing points, as the grid below could never be made, in my own DIY way and reasonable time, flat and horizontal due to the condition of the beams.

    Thanks and sorry for the very long letter…

    • Roger

      Hi Dusan,

      Is your multiplex board at 10mm below the top of your parquet strip or is there room for a properly tile underlayment over the multiplex? Because (unless it’s something different in Holland) multiplex is not something you want to bond your tile directly to. As far as it being perfectly flat, it may not be, but that can be compensated for both while installing the tile substrate and as the tile is set.

      The biggest issue, assuming your framing is now as solid as it needs to be, is that you are wanting to have the tile even with the parquet at all costs, even (it sounds to me) if it means compromising the integrity of a tile installation to achieve that. That’s completely up to you, but it will cost you more time and money in the long run. The fact that the tile does not lay completely flat on your substrate is not a major problem, it can normally be compensated for with more or less mortar beneath the tile as the tile is set.

      My opinion is that it is better to properly prepare your tile substrate and have it a bit higher than the existing flooring and then deal with a transition of some sort made of whatever material you want. A tile substrate should never be compromised simply to reach a given height of an existing floor. There are products which will keep the height down, and they can normally be used to flush the two floors, but if it needs to be higher – it needs to be higher.

      And yes, I know that’s not what you wanted to read. :D Sorry.

      • Dusan Ilic

        Thanks for the reply Roger, but I did not quite understand it i.e. the first sentence / question. I do have more than 10 mm below the parket strip i.e. there is 15/16 mm available. Tiles are 10 mm.

        This leaves 5-6 mm for the substrate / glue. I was told by all local tilers there is no problem to level the tiles with the parket stripe in this situation.

        Multiplex gets one layer of almost looking like water liquid, for prevention of wood to suck the water from the tile glue, and on a such prepared surface they put glue and tiles. I do not have space for anything else.

        I agree with you, but still there is a question: does it need to be higher, or not, given that there is this 5mm available for the glue or whatever else?

        This has become so obsessive that I am thinking of using 2 component polyurethane glue (Bison), similar to what I used to fix the mulitplex board. I am sure it could provide “good service” to the tiles, based on what I see on some samples that I tried, but maybe the 5 mm is then too thick, and tiles will sink during the installation, that is the problem to solve, i think. Maybe with levelling them in some special way and veeeeeeeeeeeeeery slow installation of one tile per day….

        • Roger

          If the combination of the ‘water liquid’ plus the thinset is 5-6mm then you will be fine with that.

  • Tony

    Hello sir I am trying to install vct tile over old vct tile by myself,after a search I am going to put underpayment on top of old vct tile screwed it down and spread the adhesive and then vct tile,
    Second I have small area of concrete 1″ higher then other floor, how I can Attach each other on higher and lower floor to look smoother and solid I will really apparitiate for advice.
    Tony

    • Roger

      Hi Tony,

      To make it look as seamless as possible you can install vct on the vertical edges around the higher slab. It can be attached directly to the sides of the concrete.

  • Robrat

    Flat Floor issue.

    I’m putting down 2″ hex marble mosaic tile on a bathroom floor (about 65 sq ft.). Sistered floor joists, 2 layers of Advantech (15# tar paper in between, 2nd layer joints staggered, avoiding screwing into joists w/2nd layer), then 1/4″ Durock bedded in thinset with a 1/4 notched trowel, and screwed per schedule. I think the floor would support a truck.

    Everything was flat, until I mesh taped the durock joints. I was real careful to push the mesh in hard, and trowel off excess thinset, but still ended up with the joints being about 1/8″ proud of the rest of the panel.

    Should I do a self leveling pour, or try to float a layer of thinset the day before tiling, or just try to deal with it as I’m laying the floor?

    Great books and site BTW, I’ve learned lots of PRACTICAL information in them and here, that you just can’t get anywhere else.

    Robrat

    • Roger

      Hi Robrat,

      If you have the real think mosaics (1/4″) then I would either use slc or float out those seams on each side with thinset the day before. If you have the thicker ones just use a bigger trowel and you can level it out as you set your tile.

  • Marcel

    Hi Roger,
    Can I use medium bed mortar (Custom Building Products Marble Granite and Travertine White 50 lb. Premium Medium Bed Mortar from Home Depot) to install 2″x2″ tiles on a small shower floor (approx 3’x3′)?

    I have two high corners (made the top slope too thick) and, midway along the wall, the floor is between 1/4″ and 1/2″ lower than the corners. Still have a little more than 1/4″/foot slope to the drain at the lowest point.

    Asking because I would like to try to make the floor tiles even along the walls using a thicker than 1/8″ substrate.
    Thanks!

    • Roger

      Hi Marcel,

      Absolutely you can, that’s a good medium bed mortar.

  • Gareth

    In preparation for installing 1/4″ Wonderboard, I renailed 1/2″ plywood to joists and then installed 3/4″ tongue and groove plywood over the top, staggering the seams and using wood glue rolled out to bond the two layers of plywood together and then screwing those layers together. Then I used a 1/4″ square notch trowel and thinset and screws to bond the 1/4″ Wonderboard to the plywood.

    My question: after all that I noticed there are some dips in the wonderboard. This is because a few of the floor joists are not the same height as the rest. The dips are about 1/4″ deep and are gradual over a 4′ length. What would you recommend to fill in the dips? Thinset or medium set?

    Thank you.

    • Roger

      Hi Gareth,

      A medium-bed mortar is what you want to use to set your tile.

  • Kevin

    Hi Roger,
    Uncovered the new deck mud floor for the bath and your truly didn’t do too thorough of a job when troweling it out and I left a slight depression in the floor where I had a kneeling board laid. We are talking about ~1/8″ dip 12″ wide by maybe 16″ long- a gradual swale. Should I fill this now to level it, or make up with thin set when setting the tile? Have yet to put the Hydro Barrier down, so I thought I’d get your advise before I muck it up- or worry it to death.

    All the best,
    Kev

    • Roger

      Hi Kevin,

      You can skim over and level that with thinset and let it cure before installing the hydrobarrier.

  • Jessica

    I’m so glad I found your site. I hope you haven’t already answered this question somewhere. I’m planning on putting ceramic penny tile on the floor of a small half bath. I’ve taken all the old linoleum and what not up and am left with 16″ spaced joists with wood planks nailed to them. The planks are 4″ wide and are perpendicular to the joists and in pretty good shape.

    I’m now planning on putting down plywood subfloor over the planks. Should I screw the plywood through the planks into the joists or should I attach the plywood just directly to the planks? I have been told different things. (I was then going to do thinset-hardieboard-thinset-tile-grout.)
    Thanks so much for any advice you can spare!

    Jessica

    • Roger

      Hi Jessica,

      Sounds like you’ve been doing your research! Screw it only to the planks, not into the joists.

      • Jessica

        Thanks!

  • kc

    Hi, I am sorry if you have answered this q already.
    I have some old vinyl peel and stick tiles ( probably asbestos). Some of them have come off when there was a leak around the toilet. And some of removed just because the corners were sticking up and bugging me. The area around the toilet is the wood of the actual house. It looks like hardwood although very old. So, there are areas where there is still the vinyl tile, areas where there is no tile, and areas where there is the black gooey gluey stuff left from the back of the tiles. What do I do to even out the whole floor before tiling. The floor seems solid( not squishy) and I believe the depth from tile to wood is no more than a 1/4″.

    • Roger

      Hi KC,

      Install a layer of 1/2″ plywood (if using a membrane) or 1/2″ backer with thinset over it and screw it down. You can not install directly over hardwood anyway, you need a substrate of some sort.

  • Tessa

    There was a leak under the toilet and as a consequence some tiles had to be removed. The plywood subfloor suffer some damage. The two top layers were wet and were removed. The area is about 2’x4′. The layers removed were very thin, but now I have a gap to fill before reinstalling the tile. I cannot find any wood panel 1/16″ . What else can I use?

    • Roger

      Hi Tessa,

      Your tile was bonded directly to plywood??? It should not be, and it should not be repaired that way either. Schluter ditra is about 1/16″. If you put a thin wood panel beneath it the water from the thinset will warp the wood and it will not stay flat nor bonded.

      • Tessa

        Thanks for your opinion, Roger. I will take a look at that.
        I was exploring using DAP Bondex Floor patch and Leveler. It is waterproof and I can use thinset to set the tiles. What do you think of it?

        • Roger

          DAP Bondex Floor patch and Leveler is not waterproof, I don’t know who told you that. Unless it is the hydraulic variety, which is not readily available, it is a cement based product only. If your tile was bonded directly to plywood it is incorrectly installed according to TCA, TCNA, and ANSI standards, as well as being my opinion. :) Ditra can be bonded to plywood, as well as most other uncoupling membranes (strata-mat, provaflex, spidermat, etc.). They can also be made to be waterproof when needed.

  • Robert Boyd

    We have pulled up the tiles in our entry 10’X 14′ the ridges from the old cement are hard to smooth out. we have been told to use floor leveler to smooth out the ruts before we put down our new vinyl tiles can you recommend a brand
    thanks

    • Roger

      Hi Robert,

      Custom’s level quick is actually one of the best, it’s available at home depot. If you just want to flatten out the ridges you can to that with thinset and the flat side of your trowel.

  • Jason

    I’m ready to tile my updated kitchen. My house is on a raised foundation and the kitchen floor currently has some 8 inch vinyl tile (not really sure of the material. house was built in 1965). There is also some new plywood on the floor in a small 5×3 section which is level to the old vinyl tiles. How do I proceed with preparing the floor for my new porcelain tile? (wide plank tile). Thin set to the surface of my current floor, then hardibacker, then thin set, then tile?? Advice is appreciated. Thanks.

    • Roger

      Hi Jason,

      It depends on the structure beneath the vinyl. You need a double layer of plywood over the joists at a minimum 1 1/8″ thickness. If you have that then yes, thinset then backer. If you don’t you’ll need to add an additional layer of plywood first.

  • doug

    SOOO… i bought your tile design and layout manual which is very informative, thank you. Unfortunately it did not answer the main question i had for buying it. This not your fault because I imagine the answer to my question is so obvious it should not even be a question. Here we go… Tiling my bathroom wall and floor, wall first, floor second. Should the bottom wall tile be hard against the floor substrate (nonshrink grout) or raised a floor-tile thickness so my grout line is under the wall tile not on the floor tile at the wall to floor interface? HMMMM… I have read this question several times and do not understand what I typed but if you can decipher my wandering convoluted ramblings please help before my wife leaves me for someone who has a functioning bathroom. THANKS

    • Roger

      Hi Doug,

      The order in which the tile sits doesn’t matter. You can have the floor tile up against the face of the wall tile or the wall tile over the floor tile. No matter which way you do it there needs to be a 1/16″ – 1/8″ gap between the tile and mud deck or tile, this gets silicone. I prefer the latter, it’s just a cleaner look to me.

      • doug

        you are a scholar and gentleman, Thank you kind sir.

  • Bonnie Janssen

    I just had tile laid in my kitchen by a professional and ended up with a less than professional job. My tiles are not flat. I guess what you call lippage. I was told I have a high floor joist and there is no other way to lay the tile. I know a backer board was installed first. I also have an issue with the grout. It is supposed to be black but not all is. Some is black some gray and some whitish. Can you help me so I can present an intelligent discussion to my installer.

    • Roger

      Hi Bonnie,
      The floor flatness is the responsibility of your installer. There are standards for allowable lippage which must be followed. If you notice it, it’s likely more than allowed.
      If the grout color is different than the sample then it’s wrong, period.

      • Bonnie Janssen

        My contractor is going to re grout but not much is being done about the way it is laid, He blames part of it on the tile as it is sort of curved on some of the ends. This is porcelain tile and has a lot of dull places in it. there are dull places that that are like the waffle design on the back of the tiles and many that just look like the floor is dirty. I have tried washing it and also used a magic eraser. When it is wet it looks like it worked but as soon as it dries it shows again. I think it is defective tile but my supplier won’t do anything about it. Do you know of anything I could use to clean or polish this tile. I feel like I have really been taken advantage of. Any help you can give will be greatly appreciated.

        • Roger

          You can get some rubbing compound (the kind used for cars) and try to buff it off. An electric buffer helps too, if you have access to one.

          • Bonnie Janssen

            Thanks. I will try that.

  • Brad

    Man this site is awesome on the one hand and on the other its making my head want to explode. Sometimes my OCD tendencies to want to make sure everything is done perfectly drive me to think that ignorance really can be bliss.

    Anywho…so that my dog doesn’t catch fire (which my wife probably wouldn’t be happy with), what should I put down on hardwoods before tile goes down? Hardwoods you say? Yeah….just bought a 100 year old house and the only flooring down is the original heart pine. No subfloor. Nothin. Should I cut out all the hardwoods in the baths and put down an OSB subfloor first or just lay cement board over the wood? What waterproofing method would be best?

    Thanks FloorElf!

    • Roger

      Hey Brad,

      I would put a layer of 1/2″ plywood over it, then the backer. You can use 1/4″ cement board on the floors if you need to save some height, doesn’t make any difference. Are you wanting to waterproof your floors? If so, rather than using 1/4″ backer use ditra. You can waterproof it by using kerdi-band over the seams.

  • Jan

    Roger, Thanks for all you help with my floor. I have completed laying my tile and grouted it. My question is, how long until I can put sealant on i?. There were no instructions on the bag.

    • Roger

      Hi Jan,

      It depends on your sealer. The time window will be on the bottle of sealer. It’s normally 72 hours, but varies by brand.

  • Rick

    Hi Roger

    My current bathroom floor contains several layers….presently it’s linoleum over a wood which is over old, probably asbestos containing floor tiles which is over something else. Must I remove all these layers down to the subfloor, or, can I lay a piece of 1/8th inch thick ply/luan over the existing linoleum then lay my 1/4 inch duroc over that?