Does my Floor have to be Level to Install Tile?

by Roger

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.

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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.

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Roger

Hi Gareth,

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

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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

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Roger

Hi Kevin,

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

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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

Reply

Roger

Hi Jessica,

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

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Jessica

Thanks!

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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″.

Reply

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.

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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?

Reply

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.

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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?

Reply

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.

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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

Reply

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.

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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.

Reply

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.

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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

Reply

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.

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doug

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

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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.

Reply

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.

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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.

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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.

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Bonnie Janssen

Thanks. I will try that.

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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!

Reply

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.

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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.

Reply

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.

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